Technical Field

The present disclosure relates to a technique for variable network capacity use of a second radio network node in a radio access network (RAN) coordinated by a first radio network node of the RAN for serving an increased demand from radio devices within the RAN.

Background

The New Radio (N R) or Fifth Generation (5G) development of the Third Generation Partnership Project (3GPP) had been expected to improve network energy efficiency to lean design by having no cell-specific reference signal (CRS) and the synchronization signal block (SSB) periodicity being by default 20ms. However, NR in the conventional implementation for some relevant use cases consumes more energy (and/or power) compared to Long Term Evolution (LTE) or the Fourth Generation (4G), partly due to higher bandwidths, shorter transmission time intervals (TTIs) and massive numbers of antennas. The increase in energy consumption is still evident even at times when cells and beams are lightly loaded or serve no traffic or even no users at all. A basic method for saving network energy is to simply turn off a next Generation Node B (gNB) or cell completely when it is seen or predicted that there is no traffic or even no user in the cell.

A problem may be encountered that when there is a large traffic demand in the coverage area of a deactivated gN B or cell, the gNB does not know about it and does not serve it, causing the performance of one or more user equipments (UE(s)) to be severely affected.

If the network deployment is a kind of heterogeneous network, where there is a gNB or cell responsible for coverage and other gNBs or cells responsible for capacity, it is more feasible to turn off a capacity cell when the traffic demand within the coverage area is not that much, as the one or more U E(s) can be served by the coverage gN B anyway.

However, when a capacity gNB or cell is turned off and there is a traffic demand which the coverage gNB or cell cannot serve efficiently or sufficiently on its own, it is necessary to turn on capacity gNB(s) or cell(s) again. Since there is not sufficient information at the coverage gNB, in conventional solutions, it will turn on all capacity gNBs or cells. Waking up an inappropriate gNB or cell cannot help to efficiently offload user traffic from coverage gNB or cell and causes a waste of power and/or energy.

Summary

Accordingly, there is a need for a technique that enables a, in particular demand based, variable use of network capacity, and/or that enables energy saving at times where the capacity demand is low. Alternatively or in addition, there is a need for a technique in which a first radio network node (also denoted as coverage radio network node, e.g., coverage gNB) wakes up one or more second radio network nodes (also denoted as capacity radio network nodes, e.g., capacity gNB(s)) and/or one or more second cells efficiently.

As to a first method aspect, a method performed by a first radio network node of a radio access network (RAN) is provided. The method comprises or initiates a step of sending a request, to at least one second radio network node of the RAN, for transmitting at least one reference signal (RS). The at least one second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access. A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

The first radio network node (also briefly: first node) may also be denoted as coverage node, always-on node, primary node, and/or macro cell. Alternatively or in addition, the first radio network node may serve a large coverage area.

Any one of the at least one second radio network nodes (also briefly: second nodes) may also be denoted as capacity node, selectively-on node (or temporarily- off node), secondary node, micro cell and/or pico cell. Alternatively or in addition, any one of the at least one second radio network nodes may serve a small (e.g., compared to the coverage area of the first radio network node) coverage area. Further alternatively or in addition, the coverage area of any one of the at least one second radio network nodes may at least partially overlap with the coverage area of the first radio network node. The RAN may also be denoted as wireless communication system, radio communication system, and/or (e.g., wireless and/or radio) telecommunications system. Alternatively or in addition, the RAN may comprise a communication system according to the 3GPP and/or Wi-Fi standards. For example, the RAN may embody at least one radio access technology (RAT), optionally including at least one of 3GPP fifth generation new radio (5G NR), 3GPP long term evolution (LTE) or Wi-Fi.

The at least one radio device may also be denoted as wireless device, and/or terminal (e.g., end terminal).

The request for transmitting at least one RS may comprise and/or may be indicative of requesting the at least one second radio network node to transmit the at least one RS.

The at least one RS, in particular transmitted by the at least one second radio network node, may enable a radio link quality measurement, in particular in relation to the at least one second network node, at and/or by the at least one radio device. The radio link quality may comprise a received power (e.g., reference signal received power, RSRP), a received quality (e.g., reference signal received quality, RSRQ), a received signal strength indicator (RSSI), a signal-to-noise ratio (SNR), and/or a signal-to-interference and noise ratio (SINR). The radio link quality measurement may be performed by the at least one radio device on RSs transmitted from the at least one second radio network node.

The energy saving mode (also denoted as sleeping or dormant mode) may comprise the at least one second radio network node (and/or at least one beam, cell, transmission and reception point (TRP) and/or distributed unit (DU) of, and/or controlled by, the at least one second radio network node) not being connected to, and/or nor serving, any radio device. Alternatively or in addition, the energy saving mode may comprise the at least one second radio network node (and/or at least one beam, cell, TRP and/or DU of, and/or controlled by, the at least one second radio network node) refraining from persistently, and/or periodically, transmitting at least one of system information, control signaling, and RSs. Herein, "connected to" may encompass "radio-connected to".

At least some embodiments of the method prompt the at least one second radio network node to transmit RSs (e.g., only) demand-actuated (also denoted as need- based). Thereby, the at least one second radio network node may remain in the energy saving mode for an extended time, and/or signaling overhead may be reduced, e.g., while including the at least one second radio network node for mobility management and/or improving radio link quality. Alternatively or in addition, a Quality of Service (QoS), and/or a Quality of Experience (QoE), may be increased for a variable number of radio devices.

In an embodiment, the at least one second radio network node may comprise and/or may serve multiple beams. Alternatively or in addition, the at least one second radio network node may comprise and/or may serve multiple cells. Alternatively or in addition, the at least one second radio network node may comprise and/or may serve multiple transmission and reception points (TRPs). Alternatively or in addition, the at least one second radio network node may comprise and/or may serve multiple distributed units (DUs).

At least one of the multiple beams, the multiple cells, the multiple TRPs, and the multiple DUs may be in the energy saving mode. The at least one RS, for which the request for transmitting has been sent by the first radio network node, may be associated with the at least one of the multiple beams, the multiple cells, the multiple TRPs, and the multiple DUs in the energy saving mode of the second radio network node.

The multiple beams (and/or beam directions) may comprise at least two beams within one cell.

The at least one second radio network node being in the energy saving mode may encompass that at least one of the multiple cells, the multiple TRPs, and the multiple DUs of the at least one second radio network node is in the energy saving mode.

The at least one second radio network node may comprise a centralized unit (CU) and the one or multiple DUs. Alternatively or in addition, the first radio network node may comprise a CU and one or more DUs. The first method aspect may be performed by the CU of the first radio network node.

In the energy saving mode, the at least one second radio network node may not provide radio access (e.g., not full cell functionality) in each cell or TRP or DU of the at least one second radio network node. The radio access (e.g., the cell functionality) may be reduced or suspended or restricted with respect to at least one or each of the one or multiple cells, or the one or multiple TRPs, or the one or multiple DUs served by the at least one second radio network node. The request for transmitting at least one RS may be indicative of the energy saving mode for a particular cell or TRP or DU of the at least one second radio network node.

The at least one second radio network node may be configured to switch between at least two or all of: an active mode (e.g., in which the first radio network node provides full cell functionality, particularly radio access, to radio devices); the energy saving mode with a capability to transmit at least one RS (which may also be denoted as positioning capability); and an energy saving mode without positioning capability (e.g., a deactivated mode). The deactivated mode may also be referred to as fully asleep.

The request, sent by the first radio network node, for transmitting at least one RS may comprise requesting the transmission of the at least one RS from at least one of the multiple cells, the multiple TRPs, and the multiple DUs, which is in the energy saving mode.

Herein, any "mode" of the at least one second radio network node may also be referred as a "state" or "role" of the at least one second radio network node.

In an embodiment, the method may further comprise or initiate a step of determining that there exists a demand for increased capacity for serving, by the RAN, at least one radio device connected to the first radio network node.

Alternatively or in addition, the request may be sent to the at least one second radio network node responsive to the determining that there exists a demand for the increased capacity.

The demand for increased capacity may comprise a number of radio devices being simultaneously connected to, and/or served by, the RAN, in particular within a predetermined coverage area.

Alternatively or in addition, determining the demand may encompass determining an overload. Optionally, the determining of the demand may trigger the step of sending the request (or performing the method disclosed herein). Alternatively or in addition, the determining may comprise checking if there is at least one radio device in coverage of the at least one second radio network node (e.g., in the coverage of a capacity cell). The at least one second radio network node (e.g., the capacity cel I, particularly a micro cell or a small cell) may be operating at a much lower downlink (DL) transmit power than the first radio network node. For example, the at least one second radio network node can therefore serve the at least one radio device (e.g., UE) more energy efficiently.

In an embodiment, the sending of the request may comprise sending the request over a fronthaul link or a backhaul link of the RAN from the first radio network node to the at least one second radio network node. The fronthaul or backhaul link may comprise an Xn-interface according to 3GPP 5G NR, and/or an X2-interface according to 3GPP LTE.

In an embodiment, the request may comprise an indication of a time for the transmitting of the at least one RS. Optionally, the indication of the time may comprise or control an aperiodic transmission, a periodic transmission, and/or a transmission within a predetermined time interval.

The time interval may also be denoted as time window.

The aperiodic transmission may comprise a single instance of a RS transmission. Alternatively or in addition, the periodic transmission may comprise transmitting at least one RS repeatedly within and/or during a predetermined time interval.

The predetermined time interval may be started by an event, e.g., the sending of the request for at least one RS, and/or may be provided in terms of frames, e.g., by one or more symbol frame numbers (SNFs).

Alternatively or in addition, the indication of the time may comprise a start time, an absolute time, a relative time-offset (e.g., relative to transmitting the request by the first radio network node, and/or to receiving the request at the at least one second radio network node).

In an embodiment, the request may comprise an indication of at least one frequency resource for use by the transmitting of the at least one RS. The at least one frequency resource may comprise at least one subchannel and/or at least one frequency range. The indicated at least one frequency resource may be indicated out of a set of predetermined frequency resources. In an embodiment, the at least one RS may comprise at least one synchronization signal block (SSB) and/or at least one channel state information RS, CSI-RS.

The SSB may be cell defining and/or non-cell defining. Non-cell defining may comprise the SSB not being provided with a synchronization raster and/or not comprising any (e.g., further) remaining minimum system information, RMSI, configuration. Alternatively or in addition, a cell defining SSB may be detected by a radio device not in an active state (e.g., in an idle state and/or an inactive state, wherein each state may also be denoted as mode). Further alternatively or in addition, a non-cell defining SSB need not, or may not, be detected by a radio device not in the active state.

The SSB may also refer to a synchronization and/or physical broadcast channel (PBCH) block, wherein the synchronization signal and the PBCH channel may be arranged as a single block in the time domain. The synchronization signal may comprise a primary synchronization signal (PSS) and a secondary synchronization signal (SSS).

In an embodiment, the request may comprise a predetermined output power level for the at least one RS. The predetermined output power level may comprise a threshold power level. Alternatively or in addition, the predetermined output power level may comprise a minimum power level for transmitting the RS from the at least one second radio network node.

In an embodiment, the request may comprise an indication of at least one beam and/or of at least one direction for the transmitting of the at least one RS by the at least one second radio network node.

The at least one beam (also: beam direction) and/or the at least one direction may be provided by the first radio network node based on a precoding matrix indicator (PMI) and/or an SSB.

In an embodiment, a resource comprised in the request for the transmission of the at least one RS may be based on a manual configuration, in particular by an operations and management (0AM) entity, and/or based on historic data of past radio link quality measurements. The historic data may relate to one or more radio devices previously located in a direction, and/or a location, close to the direction, and/or the location, of the at least one radio device which is to perform the radio link quality measurement on the requested RS transmission.

The manual configuration may in particular be used if more than one second radio network nodes are requested to transmit RSs simultaneously, and/or in temporal proximity, in particular using different resources on a time-frequency resource grid.

Alternatively or in addition, the request being based on the manual configuration, in particular by the 0AM entity, and/or the request being based on historic data of past radio link quality measurements may comprise a learning process.

The learning process may comprise at least two levels. At a first level of the learning process, a proper one of the at least one second radio network node may be selected for the request of transmitting the at least one RS. E.g., the first network node may have learnt after a predetermined number of previously received radio link quality measurement reports (and/or a predetermined number of historic data of past radio link quality measurements) that only a subset of all possible second radio network nodes is suitable for a coverage area, for which a demand for increasing capacity has been determined. E.g., further second radio network nodes, which are not in the subset, may be unsuitable (or fruitless) for one or more radio devices outside of the coverage area the further second radio network nodes.

At a second level of the learning process, within a second radio network node, only one or a proper subset of multiple beams, multiple cells, multiple TRPs and/or multiple DUs have shown to be suitable (or fruitful) based on the historic data o past radio link quality measurements (and/or based on a predetermined number of previously received radio link quality measurement reports).

Whether only one or a proper subset of multiple beams, multiple cells, multiple TRPs and/or multiple DUs is suitable (or fruitful) may be determined by observing that at least one radio device and measure at least on RS and transmit a measurement report to the first radio network node (also denoted as coverage node and/or main node). E.g., if initially a plurality or all second radio network nodes have been requested to transmit in a plurality or all of multiple beams, multiple cel Is, multiple TRPs and/or multiple DUs, but the at least one radio device only receives a RS from a specific beam, cell, TRP and/or DU of a specific second radio network node, then all other beams, cells, TRPs and/or DUs, and/or all other second radio network nodes are seen as unsuitable (or fruitless).

The learning process may comprise a, e.g., iterative, filtering and/or refinement of a granularity. The granularity may, e.g., be refined from a second radio network node to one of multiple cells of the second radio network node, and further to one of multiple beams of the one cell.

Alternatively or in addition, the learning process may further comprise the first radio network node requesting transmitting at least one RS from one or more second radio network nodes that has previously been considered as unsuitable (or fruitless), e.g., for verifying and/or cross-checking (also denoted as sanity-checking) earlier findings.

By the learning process, it can be ensured that no second radio network node energy (and/or power) is wasted unnecessarily, in particular for transmitting RSs.

In an embodiment, the request may comprise an indication for the at least one second radio network node to refrain from allowing the at least one radio device, or any radio device, to camp on, and/or to connect to, the at least one second radio network node. Optionally, the indication may comprise a timing indication including, and/or corresponding to, a time for the transmitting of the at least one RS.

The at least one second radio network node may be instructed to not allow the at least one, or any, radio device in a non-active state (e.g., in an idle state and/or in an inactive state) to camp on the cell defined by the at least one second radio network node, e.g., during, and/or shortly after, a transmission time of the at least one RS. Alternatively or in addition, the at least one second network may be instructed to not allow connecting to the at least one, or any, radio device in the active state and/or in the connected state. The connected state of a radio device may comprise the active state and/or the inactive state, but need not, or may not, comprise the idle state. Alternatively or in addition, the connected state may refer to a radio resource control (RRC) connection between a radio device and any one of the first and second radio network nodes. The at least one second radio network node refraining from allowing radio devices to camp, and/or to connect, may be denoted as the at least one second radio network node being in a barred state, a state reserved for operators, a state reserved for other use, and/or as a state for RS provisioning only.

In an embodiment, the at least one second radio network node may comprise at least two different second radio network nodes. The sending of the request for the transmitting of the at least one RS may comprise sending a request to each of the at least two different second radio network nodes. Optionally, the requests sent to different second radio network nodes may differ in terms of indications of radio resources for the at least one RS. Alternatively or in addition, the radio resources may comprise at least one time resource, at least one frequency resource, and/or at least one directional resource.

Each of the different second radio network nodes may transmit at least one RS according to (or responsive to) the respective request.

The directional resource may also be referred to as spatial resource.

In an embodiment, the method may further comprise or initiate the step of receiving, from the at least one second radio network node, feedback in relation to the request for the transmitting of the at least one RS signal.

The feedback may be received in response to the request.

In an embodiment, the received feedback may comprise an indication of an RS failure. The indication of the RS failure may comprise the at least one second radio network node being unable to transmit the at least one RS according to the request. Alternatively or in addition, the received feedback may comprise an indication of the at least one RS being transmitted according to the request. Alternatively or in addition, the received feedback may comprise an indication of radio resources allocated by the second radio network node for the at least on RS being transmitted. The radio resources allocated by the at least one second radio network node may differ from radio resources indicated in the request by the first radio network node. Optionally, the radio resources may comprise at least one time resource, at least one frequency resource, and/or at least one directional resource. The indication of the RS failure may comprise the at least one second radio network node indicating that no RS has been or will be transmitted. Alternatively or in addition, the indication of the RS failure may comprise the at least one second radio network node not using RS resources as requested by the first radio network node, but instead the at least one second radio network node allocating resources for RS transmission that differ from the request by the first radio network node.

The indication of the at least one RS being transmitted according to the request may also be referred to as a confirmation or acknowledgment of the at least one RS being transmitted according to the request.

In an embodiment, the method may further comprise or initiate a step of sending an indication, e.g. to the at least one second radio network node, to start transmitting the at least one RS.

For example, the request may configure the at least one second radio network node for the transmitting of the at least one RS. The indication to start the transmitting of the at least one RS may trigger the transmission according to the (e.g., manual) configuration and/or according to the indication comprised in the received feedback.

In an embodiment, the method may further comprise or initiate a step of transmitting a configuration message configuring the at least one radio device to perform at least one radio link quality measurement based on the at least one RS transmitted by the at least one second radio network node. The step of configuring the at least one radio device may be performed before the step of sending the indication to the at least one second radio network node to start transmitting one or more RSs.

In an embodiment, the configuration message may be transmitted by broadcast signaling and/or dedicated signaling, optionally by system information block (SIB) signaling, radio resource control (RRC) signaling, at least one medium access control control element (MAC CE) and/or downlink control information (DCI).

In an embodiment, the configuration message may be indicative of at least one predetermined radio resource for performing the at least one radio link quality measurement. Optionally, the at least one predetermined radio resource may comprise at least one predetermined time resource, at least one predetermined frequency resource, and/or at least one predetermined directional resource.

In an embodiment, the at least one predetermined time resource may comprise a time indicated by a back-off timer.

The at least one radio device may receive the configuration for the one or more radio link quality measurements before the at least one second radio network node starts transmitting RSs. Alternatively or in addition, by the back-off timer, the radio link quality measurements by the at least one radio device may be synchronized with the RS transmissions by the at least one second radio network node.

The back-off timer may be configured to prevent the at least one radio device (also denoted as UE) from camping on, and/or from connecting to, the second radio network node (and/or the at least one beam, cell, TRP, and/or DU of the second radio network node) which, e.g., temporarily, transmits the at least one RS.

The at least one radio device may be configured to perform the at least one radio link quality measurement according to the indication of at least one RS comprised in the feedback from at least a second network node, which may differ from the at least one RS comprised in the request sent by the first network node.

The at least one radio device (or UE) may be informed (e.g., via dedicated message and/or via broadcast information) by the first radio network node (e.g., a gNB) that it is prohibited to camp on the second radio network node (e.g., another gNB), and/or one or more corresponding cells, for a period of time, e.g., according to the back-off timer, and/or while the radio link quality measurement on the at least on RS is ongoing. Based on this information, the radio device (e.g., UE) may refrain from camping on, and/or accessing, the one or more corresponding cell of the second radio network node (e.g., gNB).

In an embodiment, the configuration message may comprise an indication to the at least one radio device to refrain from camping on, and/or connecting to, a cell defined by the at least one second radio network node and/or by the at least one RS during a predetermined time interval, optionally. The predetermined time interval comprises may predetermine time resources for the radio link quality measurement. In an embodiment, further may comprise or initiating the step of receiving, from the at least one radio device, a radio link quality report. The radio link quality report may be based on the at least one radio link quality measurement of the at least one RS.

In an embodiment, the received radio link quality report may be indicative of a reference signal received power (RSRP), a reference signal received quality (RSRQ), a received signal strength indicator (RSSI) a signal-to-noise ratio (SNR), and/or a signal-to-interference and noise ratio (SINR).

The radio link quality report may also be denoted as radio resource management (RRM) report.

In an embodiment, the received radio link quality report may be indicative of an area or location of the at least one radio device at the time of the at least one radio device performing the radio link quality measurement and/or of the transmitting of the radio link quality report. Alternatively or in addition, the first radio network node may be aware of the area or location of the at least one radio device.

Optionally, the area or location may be indicated by at least one of a beam in relation to the at least one RS received from the at least one second radio network node, and/or in relation to an uplink (UL) transmission to the first radio network node. Optionally, the UL transmission may comprise the radio link quality report.

Alternatively or in addition, the area or location may be indicated by at least one of an angle of arrival in relation to the at least one RS received from the at least one second radio network node, and/or in relation to an UL transmission to the first radio network node. Optionally, the UL transmission may comprise the radio link quality report.

Alternatively or in addition, the area or location may be indicated by at least one of a timing advance (TA) value in relation to an UL transmission to the first radio network node. Optionally, the UL transmission may comprise the radio link quality report.

Alternatively or in addition, the area or location may be indicated by a geographical position derived from a geolocation system. The geolocation system may comprise a global navigation satellite system (GNSS), e.g., the Global Position System (GPS) and/or Galileo.

The TA may alternatively be used for any connection of the at least one radio device to the first radio network node, e.g., for any UL transmission, and/or any further connection to a further radio network node. E.g., the TA may be extracted from a random access response (RAR) received by the at least one radio device from the further radio network node.

By the piece of information of the TA, the angle of arrival, and/or the beam, a predicted area and/or predicted location of the at least one radio device (e.g., UE) may be determined. The predicted area and/or predicted location may in some examples be confirmed and/or narrowed by combining at least two pieces of information.

In an embodiment, the radio link quality reports on the at least two different second radio network nodes may be received separately and/or may be received as a multiplexed report.

The configuration message may configure the at least one radio device to perform the radio link quality measurement for each of the at least two different second radio network nodes.

In an embodiment, the radio link quality report may be received at the first radio network node by a re-routing. Optionally, the re-routing may comprise a sidelink (SL) from a further radio device.

The radio link quality report may be received at the first radio network node through a further radio device on a SL. The further radio device may also be noted as relay radio device.

In an embodiment, the method may further comprise or initiate a step of storing the received radio link quality report.

In an embodiment, the method may further comprise or initiate a step of determining, based on the received radio link quality report, that the at least one second radio network node, and/or at least one of at least two second radio network nodes, may be suitable for serving the at least one radio device. Alternatively or in addition, the method may further comprise or initiate a step of sending an activation request to the at least one second radio network node, which has been determined suitable for serving the at least one radio device. Alternatively or in addition, the method may further comprise or initiate the step of transmitting a configuration message configuring the at least one radio device to camp on, and/or to connect to, the cell defined by the at least one second radio network node, which has been determined suitable for serving the at least one radio device.

Based on the received radio link quality report, the at least one second radio network node and/or at least one of at least two second radio network nodes may be determined suitable to fulfill the demand for the increased capacity for serving the at least one radio device.

Activating the at one second radio network node may also be denoted as (e.g., fully) waking up and/or turning on the at one second radio network node.

In an embodiment, the step of determining may be further based on a coverage area of the at least one second radio network node, and/or the at least one of at least two second radio network nodes, and/or based on previously received radio link quality reports.

The previously received radio link quality reports may be stored at the first radio network node.

In an embodiment, the at least one radio device may comprise at least two radio devices. A radio link quality report may be received from each of the at least two radio devices, and. The step of determining the at least one second radio network node may be based on the combination of the received radio link quality reports of the at least two radio devices.

In an embodiment, the at least one second radio network node may comprise at least two second radio network nodes. The determining may comprise selecting a subset of the at least two second radio network nodes based on the received radio link quality reports of each of the at least two radio devices. In an embodiment, the first radio network node may serve a macro cell. In an embodiment, the at least one second radio network node may serve a micro cell, and/or a pico cell.

In an embodiment, the request may be sent to the at least one second radio network node periodically according to a predetermined periodicity and/or responsive to a predetermined event. Optionally, the predetermined event may comprise a deployment of the RAN and/or a deployment of at least one further second radio network node for the RAN.

Herein, predetermined may encompass at least one of configured (e.g., by an operations, administration and maintenance, 0AM, entity) or predefined (e.g., by a technical specification).

The predetermined periodicity may comprise, e.g., once within a predetermined number of weeks, e.g., once per week or once per month.

The event may comprise any change in the location and/or in the configuration of any one of the first radio network node and the at least one second radio network node.

Optionally, the event may comprise a configuration change of at least a radio network node of the RAN. For example, the change may be a change of an antenna configuration, a MIMO configuration and/or a change of the downlink power.

For example, the at least one second radio network node (to each of which the request is sent) may comprise all second radio network nodes of the RAN that are neighboring radio network nodes of a further deployed second radio network node.

As to a second method aspect, a method performed by a second radio network node of a radio access network (RAN) is provided. The second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access. The method comprises or initiates a step of receiving, from a first radio network node of the RAN, a request for transmitting at least one reference signal (RS). A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node. In an embodiment, the method may further comprise or initiate a step of allocating radio resources for the transmitting of the at least one RS. Optionally, the radio resources may comprise at least one time resource, at least one frequency resource, and/or at least one directional resource.

In an embodiment, the method may further comprise or initiate a step of transmitting the at least one RS.

The second method aspect may further comprise any feature and/or any step disclosed in the context of the first method aspect, or a feature and/or step corresponding thereto, e.g., a receiver or network counterpart to a transmitter or radio device feature or step.

As to a third method aspect, a method performed by a radio device connected to a first radio network node of a radio access network (RAN) is provided. The method comprises or initiates a step of receiving, from the first radio network node, a configuration message configuring the radio device to perform at least one radio link quality measurement based on at least one reference signal (RS) transmitted by at least one second radio network node of the RAN. The at least one second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access.

In an embodiment, the method may further comprise or initiate a step of performing at least one radio link quality measurement according to the received configuration message.

In an embodiment, the method may further comprise or initiate a step of transmitting a radio quality link report to the first radio network node. The radio quality link report may be indicative of a result of the at least one radio link quality measurement of the at least one RS.

In an embodiment, the radio quality link report may be transmitted if, or only if, a predetermined quality threshold is met and/or exceeded. Optionally, the predetermined quality threshold may comprise an absolute threshold of the radio link quality. Alternatively or in addition, the predetermined quality threshold may comprise a relative threshold of the radio link qualities of a plurality of RSs. The radio device may determine to only transmit a radio link quality report, and/or to only include the result of the measurement of the radio link quality in a radio link quality report for a predetermined number of RSs of highest quality among all RSs received at the radio device. Alternatively or in addition, the radio device may determine to only transmit a radio link quality report, and/or to only include the result of the measurement of the radio link quality in a radio link quality report if the radio link quality of a RS meets and/or exceeds a predetermined radio link quality threshold.

The third method aspect may further comprise any feature and/or any step disclosed in the context of the first and/or second method aspect, or a feature and/or step corresponding thereto, e.g., a network counterpart to a radio device feature or step.

As to another aspect, a computer program product is provided. The computer program product comprises program code portions for performing any one of the steps of the first and/or second and/or third method aspect disclosed herein when the computer program product is executed by one or more computing devices. The computer program product may be stored on a computer-readable recording medium. The computer program product may also be provided for download, e.g., via the radio network, the RAN, the Internet and/or the host computer.

Alternatively, or in addition, the method may be encoded in a Field-Programmable Gate Array (FPGA) and/or an Application-Specific Integrated Circuit (ASIC), or the functionality may be provided for download by means of a hardware description language.

As to a first device aspect, a first radio network node of a radio access network (RAN) is provided. The first radio network node is configured to send a request, to at least one second radio network node of the RAN, for transmitting at least one reference signal (RS). The at least one second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access. A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

As to a second device aspect, a second radio network node of a radio access network (RAN) is provided. The second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access. The second radio network node is configured to receive, from a first radio network node of the RAN, a request for transmitting at least one reference signal (RS). A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

As to a third device aspect, a radio device connected to a first radio network node of a radio access network (RAN) is provided. The radio device is configured to may receive, from the first radio network node, a configuration message configuring the radio device to perform at least one radio link quality measurement based on at least one RS transmitted by at least one second radio network node of the RAN. The at least one second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access.

As to a further first device aspect, a first radio network node of a radio access network (RAN) is provided. The first radio network node comprises memory operable to store instructions and processing circuitry (e.g., one or more processors) operable to execute the instructions. Thereby, the first radio network node is operative to send a request, to at least one second radio network node of the RAN, for transmitting at least one reference signal (RS). The at least one second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access. A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

As to a further second device aspect, a second radio network node of a radio access network (RAN) is provided. The second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access. The second radio network node comprises memory operable to store instructions and processing circuitry (e.g., one or more processors) operable to execute the instructions. Thereby, the second radio network node is operative to receive, from a first radio network node of the RAN, a request for transmitting at least one reference signal (RS) radio network node. A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

As to a further third device aspect, a radio device connected to a first radio network node of a radio access network (RAN) is provided. The radio device comprises memory operable to store instructions and processing circuitry (e.g., one or more processors) operable to execute the instructions. Thereby, the radio device is operative to receive, from the first radio network node, a configuration message configuring the radio device to perform at least one radio link quality measurement based on at least one RS transmitted by at least one second radio network node of the RAN. The at least one second radio network node is in an energy saving mode. The energy saving mode may comprise refraining from providing radio access.

According to a still further aspect, the first device aspect, the second device aspect, the further first device aspect, or the further second device aspect may be embodied by a base station (BS).

According to a still further aspect, the third device aspect or the further third device aspect may be embodied by a user equipment (UE).

As to a system aspect, a communication system including a host computer comprising processing circuitry configured to provide user data is provided. A communication interface of the host computer is configure to forward the user data to a cellular (or ad hoc) radio network for transmission to a user equipment (UE). The radio network may comprise a first base station. The first base station may comprise a radio interface and processing circuitry, the processing circuitry of the first base station being configured to execute any one of the steps of the first method aspect.

In an embodiment, the radio network may further comprise a second base station. The second base station may comprise a radio interface and processing circuitry, the processing circuitry of the second base station being configured to execute any one of the steps of the second method aspect.

In an embodiment, communication system may further include the UE. The UE may comprise a radio interface and processing circuitry, the processing circuitry of the UE being configured to execute any of the steps of the third method aspect.

In an embodiment, the processing circuitry of the host computer may be configured to execute a host application, thereby providing the user data. Alternatively or in addition, the processing circuitry of the UE may be configured to execute a client application associated with the host application. In any aspect, any one of the at least one second radio network nodes may comprise, and/or serve, multiple beams, multiple cells, multiple transmission and reception points (TRPs), and/or multiple distributed units (DUs). The at least one second radio network node being in an energy saving mode may refer to at least one of the multiple beams, multiple cells, multiple TRPs, and/or multiple DUs of the at least one second radio network node being in the energy saving state. The request for transmitting at least one RS may be associated with the at least one of the multiple beams, multiple cells, multiple TRPs, and/or multiple DUs in the energy saving mode.

The technique may be applied in the context of 3GPP New Radio (NR). The technique may be implemented in accordance with a 3GPP specification, e.g., for 3GPP release 18. The technique may be implemented as an extension of 3GPP TS 38.423 V17.0.0.

Any of the radio devices may be a 3GPP user equipment (UE) or a Wi-Fi station (STA). The radio device may be a mobile or portable station, a device for machinetype communication (MTC), a device for narrowband Internet of Things (NB-loT) or a combination thereof. Examples for the UE and the mobile station include a mobile phone, a tablet computer and a self-driving vehicle. Examples for the portable station include a laptop computer and a television set. Examples for the MTC device or the NB-loT device include robots, sensors and/or actuators, e.g., in manufacturing, automotive communication and home automation. The MTC device or the NB-loT device may be implemented in a manufacturing plant, household appliances and consumer electronics.

Whenever referring to the RAN, the RAN may be implemented by one or more base stations.

The base station may encompass any station that is configured to provide radio access to any of the radio devices. The base stations may also be referred to as cell, transmission and reception point (TRP), radio access node or access point (AP). The base station and/or the relay radio device may provide a data link to a host computer providing the user data to the remote radio device or gathering user data from the remote radio device. Examples for the base stations may include a 3G base station or Node B, 4G base station or eNodeB, a 5G base station or gNodeB, a Wi-Fi AP and a network controller (e.g., according to Bluetooth, ZigBee or Z-Wave). The RAN may be implemented according to the Global System for Mobile Communications (GSM), the Universal Mobile Telecommunications System (UMTS), 3GPP Long Term Evolution (LTE) and/or 3GPP New Radio (NR).

Any aspect of the technique may be implemented on a Physical Layer (PHY), a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a packet data convergence protocol (PDCP) layer, and/or a Radio Resource Control (RRC) layer of a protocol stack for the radio communication.

Herein, referring to a protocol of a layer may also refer to the corresponding layer in the protocol stack. Vice versa, referring to a layer of the protocol stack may also refer to the corresponding protocol of the layer. Any protocol may be implemented by a corresponding method.

Any one of the devices, the UE, the base station, the communication system or any node or station for embodying the technique may further include any feature disclosed in the context of the method aspect, and vice versa. Particularly, any one of the units and modules disclosed herein may be configured to perform or initiate one or more of the steps of the method aspect.

Brief Description of the Drawings

Further details of embodiments of the technique are described with reference to the enclosed drawings, wherein:

Fig. 1 shows a schematic block diagram of an embodiment of a first device, in particular a first radio network node;

Fig. 2 shows a schematic block diagram of an embodiment of a second device, in particular a second radio network node;

Fig. 3 shows a schematic block diagram of an embodiment of a third device, in particular a radio device;

Fig. 4 shows a flowchart for a first method, which method may be implementable by the device of Fig. 1; Fig. 5 shows a flowchart for a second method, which method may be implementable by the device of Fig. 2;

Fig. 6 shows a flowchart for a third method, which method may be implementable by the device of Fig. 3;

Fig. 7 schematically illustrates a first example of a radio access network (RAN) comprising embodiments of the devices of Figs. 1, 2, and 3 for performing the methods of Figs. 4, 5, and 6, respectively;

Fig. 8 schematically illustrates functional entities and interfaces of two radio network nodes of a RAN, which may embody the devices of Figs. 1 and 2 performing the methods of Figs. 4 and 5, respectively;

Figs. 9A and 9B schematically illustrate signaling diagrams for a first radio network node updating a configuration of a second radio network node with acknowledgement signaling in Fig. 9A and failure signaling in Fig. 9B, wherein the first radio network node and the second radio network node may embody the devices of Fig. 1 and 2, respectively;

Fig. 10A and 10B schematically illustrate signaling diagrams for a first radio network node sending an activation request to a second radio network node with activation response in Fig. 10A and activation failure signaling in Fig. 10B, wherein the first radio network node and the second radio network node may embody the devices of Fig. 1 and 2, respectively;

Fig. 11 schematically illustrates a second example of a RAN comprising a first radio network node, two second radio network nodes and two radio devices as embodiments of the devices of Figs. 1, 2, and 3, respectively, for performing the methods of Figs. 4, 5, and 6, respectively;

Fig. 12 shows a schematic block diagram of a first radio network node embodying the device of Fig. 1;

Fig. 13 shows a schematic block diagram of a second radio network node embodying the device of Fig. 2; Fig. 14 shows a schematic block diagram of a radio device embodying the device of Fig. 3;

Fig. 15 schematically illustrates an example telecommunication network connected via an intermediate network to a host computer;

Fig. 16 shows a generalized block diagram of a host computer communicating via a base station or radio device functioning as a gateway with a user equipment over a partially wireless connection; and

Figs. 17 and 18 show flowcharts for methods implemented in a communication system including a host computer, a base station or radio device functioning as a gateway and a user equipment.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as a specific network environment in order to provide a thorough understanding of the technique disclosed herein. It will be apparent to one skilled in the art that the technique may be practiced in other embodiments that depart from these specific details. Moreover, while the following embodiments are primarily described for a New Radio (NR) or 5G implementation, it is readily apparent that the technique described herein may also be implemented for any other radio communication technique, including a Wireless Local Area Network (WLAN) implementation according to the standard family IEEE 802.11, 3GPP LTE (e.g., LTE-Advanced or a related radio access technique such as MulteFire), for Bluetooth according to the Bluetooth Special Interest Group (SIG), particularly Bluetooth Low Energy, Bluetooth Mesh Networking and Bluetooth broadcasting, for Z-Wave according to the Z-Wave Alliance or for ZigBee based on IEEE 802.15.4.

Moreover, those skilled in the art will appreciate that the functions, steps, units and modules explained herein may be implemented using software functioning in conjunction with a programmed microprocessor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP) or a general purpose computer, e.g., including an Advanced RISC Machine (ARM). It will also be appreciated that, while the following embodiments are primarily described in context with methods and devices, the invention may also be embodied in a computer program product as well as in a system comprising at least one computer processor and memory coupled to the at least one processor, wherein the memory is encoded with one or more programs that may perform the functions and steps or implement the units and modules disclosed herein.

Fig. 1 schematically illustrates a block diagram of an embodiment of a first device, e.g., a first radio network node of a RAN. The first device is generically referred to by reference sign 100.

The device 100 comprises a reference signal (RS) request sending module 104 that is configured to sending a request, to at least one second radio network node of the RAN, for transmitting at least one RS. The at least one second radio network node is in an energy saving mode. The energy saving mode comprises refraining from providing radio access. A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

In the context of any one of the devices 100; 200; 300 and/or methods 400; 500; 600 disclosed herein, any one of the at least one second radio network nodes may comprise, and/or serve, multiple beams, multiple cells, multiple transmission and reception points (TRPs), and/or multiple distributed units (DUs). The at least one second radio network node being in an energy saving mode may refer to at least one of the multiple beams, multiple cells, multiple TRPs, and/or multiple DUs of the at least one second radio network node being in the energy saving state. The request for transmitting, by the at least one second radio network node, at least one RS may be associated with the at least one of the multiple beams, multiple cells, multiple TRPs, and/or multiple DUs in the energy saving mode.

Optionally, the device 100 comprises a capacity determination module 102 that is configured to determine a demand for increased capacity for serving, by the RAN, at least one radio device connected to the first radio network node. The request may be sent to the at least one second radio network node responsive to the determined demand for the increased capacity.

Further optionally, the device 100 comprises a feedback reception module 106 that is configured to receive, from the at least one second radio network node, a feedback in relation to the request for the transmitting of the at least one RS signal. Further optionally, the device 100 comprises a RS start sending module 108 that is configured to send an indication, to the at least one second radio network node, to start transmitting the at least one RS.

Further optionally, the device 100 comprises a configuration transmission module 110 that is configured to transmit a configuration message configuring the at least one radio device to perform at least one radio link quality measurement based on the at least one RS transmitted by the at least one second radio network node.

Further optionally, the device 100 comprises a measurement report reception module 112 that is configured to receive, from the at least one radio device, a radio link quality report, wherein the radio link quality report is based on the at least one radio link quality measurement of the at least one RS.

Further optionally, the device 100 comprises a suitability determination module 114 that is configured to determine, based on the received radio link quality report, that the at least one second radio network node, and/or at least one of at least two second radio network nodes, is suitable for serving the at least one radio device.

Further optionally, the device 100 comprises an activation request sending module 116 that is configured to send an activation request to the at least one second radio network node, which has been determined suitable for serving the at least one radio device.

Still further optionally, the device 100 comprises a configuration transmission module 118 that is configured to transmit a configuration message configuring the at least one radio device to camp on, and/or to connect to, the cell defined by the at least one second radio network node, which has been determined suitable for serving the at least one radio device.

Any of the modules of the device 100 may be implemented by units configured to provide the corresponding functionality.

The device 100 may also be referred to as, or may be embodied by, the first radio network node (or briefly: first node). The first radio network node 100 and a second radio network node may be in direct wired and/or radio communication, e.g., at least for the sending of the request for transmitting one or more RSs. The second radio network node may be embodied by the device 200. Alternatively or in addition, the first radio network node 100 and at least one radio device may be in direct radio communication, e.g., at least for transmitting the configuration message configuring the at least one radio device to perform at least one radio link quality measurement based on the at least one RS transmitted by the at least one second radio network node. The at least one radio device may be embodied by the device 300.

Fig. 2 schematically illustrates a block diagram of an embodiment of a second device, e.g., a second radio network node of a RAN. The second device is generically referred to by reference sign 200.

The device 200 comprises a RS request reception module 204 that is configured to receive, from a first radio network node of a RAN, a request for transmitting at least one RS. The second radio network node is in an energy saving mode. The energy saving mode comprises refraining from providing radio access. A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

Optionally, the device 200 comprises a RS allocation module 205 that is configured to allocate radio resources for the transmitting of the at least one RS. Optionally, the radio resources comprise at least one time resource, at least one frequency resource, and/or at least one directional resource.

Further optionally, the device 200 comprises a feedback sending module 206 that is configured to send, to the first radio network node , a feedback in relation to the request for the transmitting of the at least one RS signal.

Further optionally, the device 200 comprises a RS start reception module 208 that is configured to receive, from the first radio network node, an indication to start transmitting the at least one RS.

Further optionally, the device 200 comprises a RS transmission module 211 that is configured to transmit the at least one RS.

Still further optionally, the device 200 comprises an activation request reception module 216 that is configured to receive an activation request from the first radio network node, if the second radio network node has been determined, by the first radio network node, suitable for serving the at least one radio device.

Any of the modules of the device 200 may be implemented by units configured to provide the corresponding functionality.

The device 200 may also be referred to as, or may be embodied by, the second radio network node (briefly: second node). The first radio network node and the second radio network node 200 may be in direct wired and/or radio communication, e.g., at least for the reception of the request for transmitting at least one RS from first radio network node to the second radio network node 200. The first radio network node may be embodied by the device 100. Alternatively or in addition, the at least one radio device and the second radio network node 200 may be in direct radio communication, e.g., at least for performing at least one radio link quality measurement at the at least one radio device based on the at least one RS transmitted by the second radio network node 200. The at least one radio device may be embodied by the device 300.

Fig. 3 schematically illustrates a block diagram of an embodiment of a third device, e.g., a radio device connected to the RAN. The third device is generically referred to by reference sign 300.

The device 300 comprises a configuration reception module 310 that is configured to receive, from a first radio network node of the RAN, a configuration message configuring the radio device to perform at least one radio link quality measurement based on at least one RS transmitted by at least one second radio network node. The at least one second radio network node is in an energy saving state. The energy saving state comprises refraining from providing radio access.

Optionally, the device 300 comprises a measurement module 311 that is configured to perform at least one radio link quality measurement according to the received configuration message.

Further optionally, the device 300 comprises a report transmission module 312 that is configured to transmit a radio quality link report to the first radio network node. The radio quality link report may be indicative of a result of the at least one radio link quality measurement of the at least one RS. Still further optionally, the device 300 comprises a configuration reception module 318 that is configured to receive, from the first radio network node, a configuration message. The configuration message may configure the at least one radio device to camp on, and/or to connect to, the cell defined by at least one second radio network node, which has been determined suitable for serving the at least one radio device.

Any of the modules of the device 300 may be implemented by units configured to provide the corresponding functionality.

The device 300 may also be referred to as, or may be embodied by, the radio device. The first radio network node and the radio device 300 may be in direct radio communication, e.g., at least for the reception of the configuration message to perform at least one radio link quality measurement at the radio device 300. The first radio network node may be embodied by the device 100. Alternatively or in addition, at least one second radio network node and the radio device 300 may be in direct radio communication, e.g., at least for performing at least one radio link quality measurement at the at least one radio device 300 based on the at least one RS transmitted by the second radio network node. The at least second radio network node may be embodied by the device 200.

Fig. 4 shows an example flowchart for a method 400 of performed by a first radio network node of a RAN, the RAN further comprising at least one second radio network node in an energy saving mode.

In a step 404, a request is sent (to the at least one second radio network node) for transmitting at least one RS. The at least one second radio network node is in an energy saving mode. The energy saving mode comprises refraining from providing radio access. A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

Optionally, in a step 402, a demand for increased capacity for serving, by the RAN, at least one radio device connected to the first radio network node is determined. The request may be sent 404 to the at least one second radio network node responsive to the determined demand for the increased capacity. Further optionally, in a step 406, a feedback in relation to the request for the transmitting of the at least one RS signal is received from the at least one second radio network node.

Further optionally, in a step 408, an indication is sent (to the at least one second radio network node) to start transmitting the at least one RS.

Further optionally, in a step 410, a configuration message is transmitted to at least one radio device. The configuration message may configure the at least one radio device to perform at least one radio link quality measurement based on the at least one RS transmitted by the at least one second radio network node.

Further optionally, in a step 412, a radio link quality report is received from the at least one radio device. The radio link quality report may be based on the at least one radio link quality measurement of the at least one RS.

Further optionally, in a step 414, based on the received 412 radio link quality report, it is determined that the at least one second radio network node, and/or at least one of at least two second radio network nodes, is suitable for serving the at least one radio device.

Further optionally, in a step 416, an activation request is sent to the at least one second radio network node, which has been determined 414 suitable for serving the at least one radio device.

Still further optionally, in a step 418, a configuration message is transmitted to the at least one radio device. The configuration message may configure the at least one radio device to camp on, and/or to connect to, the cell defined by the at least one second radio network node, which has been determined 414 suitable for serving the at least one radio device.

The method 400 may be performed by the device 100. For example, the modules 102, 104, 106, 108, 110, 112, 114, 116 and 118 may perform the steps 402, 404, 406, 408, 410, 412, 414, 416 and 418, respectively.

Fig. 5 shows an example flowchart for a method 500 performed by a second radio network node of a RAN, wherein the second radio network node is in an energy saving mode. In a step 504, a request for transmitting at least one RS is received from a first radio network node of the RAN. The second radio network node is in an energy saving mode. The energy saving mode comprises refraining from providing radio access. A coverage area of the second radio network node at least partially overlaps with a coverage area of the first radio network node.

Optionally, in a step 505, radio resources for the transmitting of the at least one RS are allocated. Optionally, the radio resources may comprise at least one time resource, at least one frequency resource, and/or at least one directional resource.

Further optionally, in a step 506, a feedback in relation to the request for the transmitting of the at least one RS signal is sent to the first radio network node.

Further optionally, in a step 508, an indication is received, from the first radio network node, to start transmitting the at least one RS.

Further optionally, in a step 511, the at least one RS is transmitted.

Still further optionally, in a step 516, an activation request is received from the first radio network node, if the second radio network node has been determined, by the first radio network node, suitable for serving the at least one radio device.

The method 500 may be performed by the device 200. For example, the modules 204, 205, 206, 208, 211 and 216 may perform the steps 504, 505, 506, 508, 511 and 516, respectively.

Fig. 6 shows an example flowchart for a method 600 performed by a radio device connected to a first radio network node of a RAN.

In a step 610, a configuration message is received from the first radio network node. The configuration message may configure the radio device to perform at least one radio link quality measurement based on at least one RS transmitted by at least one second radio network node of the RAN. The at least one second radio network node may be in an energy saving mode. The energy saving mode may comprise refraining from providing radio access. Optional ly, in a step 611, at least one radio link quality measurement is performed according to the received configuration message (e.g., in the step 610).

Further optionally, in a step 612, a radio quality link report is transmitted to the first radio network node. The radio quality link report may be indicative of a result of the at least one radio link quality measurement of the at least one RS.

Still further optionally, in a step 618, a configuration message is received from the first radio network node. The configuration message may configure the at least one radio device to camp on, and/or to connect to, the cell defined by at least one second radio network node, which has been determined suitable for serving the at least one radio device.

The method 600 may be performed by the device 300. For example, the modules 310, 311, 312 and 318 may perform the steps 610, 611, 612 and 618, respectively.

In any aspect, by the inventive technique a variable network capacity use may be enabled while saving energy (and/or power) whenever the demand for network capacity is low.

Alternatively or in addition, the inventive technique comprises method 400, 500 and 600 that enable a first radio network node (e.g., a RAN node, in particular a gNB) 100 to request one or more second radio network nodes (e.g., another RAN node, in particular another gNB) 200, which without loss of generality is assumed to be not fully active or awake at the time of request, to transmit one or more RSs, e.g., channel state information RS (CSI-RS) and/or synchronization signal block (SSB), temporarily at a certain time and/or for a certain period.

The proposed methods 400, 500 and 600 may have several practical use cases or applications. In one aspect, the methods 400, 500 and 60 let a first radio network node (e.g., a coverage gNB) 100 know clearly which second radio network node (e.g., capacity gNB) 200 or cell to wake up for successful traffic offloading in case of overload due to increasing traffic demand (e.g., due to an increase in a number of radio devices 300), without excessive manual operations and management (O&M) configurations and without waking up of second radio network nodes (e.g., capacity gNBs) 200 or cells blindly and/or uselessly (e.g., waking up a larger number of second radio network nodes 200 than required for the capacity increase and/or waking up second radio network nodes 200 with coverage areas not suitable for increasing the capacity at the locations of radio devices 300). When there is a higher capacity demand (also denoted as traffic demand) than what the first radio network node (e.g., coverage cell and/or coverage gNB) 100 can serve adequately, and/or when there is another reason for a need for RSs from second radio network nodes 200 in an energy saving state (also denoted as other currently sleeping or inactive gNBs or cells), the first radio network node (e.g., coverage gNB) 100 may request one or more second radio network nodes (e.g., capacity gNBs) 200 to transmit the needed RSs, e.g., temporarily.

The first radio network node (e.g., coverage gNB) 100 may inform one or more radio devices (e.g., UE(s)) 300, which it currently serves, e.g., radio devices 300 that are in the coverage area of the first radio network node 100, to perform neighbor cell measurements, e.g., at a specific time and/or for a specific period (e.g., as acknowledged by the corresponding second radio network node 200 and/or neighboring gNB). With the measurement results obtained from one or more radio devices (e.g., UE(s)) 300 for potentially different second radio network nodes (e.g., capacity cells) 200, the first radio network node (e.g., coverage gNB) 100 may know which second radio network node (e.g., capacity cell) 200 can (e.g., best) serve at least part of the capacity demand and/or traffic demand and may trigger the corresponding second radio network node (e.g., capacity gNB) 200 or cell to work in normal mode, e.g., via a cell activation procedure.

The technique may be applied to uplink (UL) and/or downlink (DL) communications, e.g., for increasing the UL and/or DL capacity on a demand basis.

Each of the first radio network node 100 and the at least one second radio network node 200 may a base station. Alternatively or in addition, the at least one radio device 300 may be a user equipment (UE) and/or end terminal. Herein, any radio device may be a mobile or portable station and/or any radio device wirelessly connectable to a base station or RAN, or to another radio device. For example, the radio device may be a user equipment (UE), a device for machinetype communication (MTC) or a device for (e.g., narrowband) Internet of Things (loT). Two or more radio devices may be configured to wirelessly connect to each other, e.g., in an ad hoc radio network or via a 3GPP SL connection. Furthermore, any base station may be a station providing radio access, may be part of a radio access network (RAN) and/or may be a node connected to the RAN for controlling the radio access. For example, the base station may be an access point, for example a Wi-Fi access point.

Fig. 7 shows an illustrative example a deployment of a heterogeneous RAN 700 comprising a first radio network node 100 (also denoted as coverage-providing node, briefly: coverage node, e.g. comprising a first Next Generation Node B, gNB 1) and two second radio network nodes 200 (also denoted as capacityproviding nodes, briefly: capacity nodes, e.g., comprising a second and third Next Generation Node B, gNB 2 and gNB 3).

The first radio network node 100, and/or the associated cell, in Fig. 7 spans a large coverage area 702, e.g., a macro cell. The second radio network nodes 200, and/or the associated cells, in Fig. 7 each span smaller coverage areas 704, e.g., micro cells and/or pico cells, that (e.g., fully) overlap with the coverage area 702 of the first radio network node 100.

Two radio devices 300 in Fig. 7 are located only in the coverage area 702 of the first radio network node 100, with two further radio devices 300 in Fig. 7 located also in the coverage are 704 of one of the second radio network nodes 200.

Fig. 8 shows an example of a 5G (also denoted as Next Generation, NG, and/or New Radio, NR) RAN architecture, which may extend the conventional 5G (also denoted as Next Generation, NG, and/or New Radio, NR) RAN architecture, e.g., as depicted and described in TS 38.401 V15.4.0.

The 5G RAN of Fig. 8 comprises of a set of radio network nodes (e.g., gNBs) 100; 200, each connected to a 5G core network (5GC) 802 through an NG interface 804. Any radio network node (e.g., gNB) 100; 200 may support frequency division duplex (FDD) mode, time division duplex (TDD) mode and/or dual mode operation. The radio network nodes (e.g., gNBs), e.g., a first radio network node 100 and a second radio network node 200, may be interconnected through a fronthaul and/or backhaul interface (e.g., an Xn interface) 806.

Any one of the radio network nodes (e.g., gNBs) 100; 200 in Fig. 8 comprises a centralized unit (e.g., gNB-CU) 810 and one or more distributed units (e.g., gNB- DUs) 812. A centralized unit (e.g., gNB-CU) and a distributed unit (e.g., gNB-DU) within a radio network node (e.g., gNB) 100; 200 are connected via an interface 80 (e.g., an Fl interface). One distributed unit (e.g., gNB-DU) 812 is conventionally connected to (e.g., only) one centralized unit (e.g., gNB-CU) 810. For resiliency, a distributed unite (e.g., gNB-DU) 812 may also be connected to multiple centralized units (e.g., gNB-CU) 810 by appropriate implementation. Each of the exemplary interfaces 804 (e.g., NG), 806 (e.g., Xn) and 808 (e.g., Fl) in Fig. 8 are logical interfaces.

The 5G RAN (or NG-RAN) may be further layered into a Radio Network Layer (RNL) and a Transport Network Layer (TNL). The 5G RAN (or NG-RAN) architecture, e.g., comprising the 5G RAN (or NG-RAN) radio network nodes (and/or logical nodes) 100; 200 and the interfaces 806 between them, may be defined as part of the RNL. For each 5G RAN (or NG-RAN) interface (e.g., NG, Xn, and/or Fl) 804; 806; 808, the related TNL protocol and the functionality are specified. The TNL provides services for user plane transport and signaling transport.

A 5G radio network node (e.g., 5G gNB) 100; 200 may be connected to a 4G radio network node (e.g., LTE eNB) 100; 200 via an interface 806 (e.g., an X2 interface). An architectural option is that a 4G radio network node (e.g., LTE eNB) is connected to the Evolved Packet Core (EPC) and is also connected over the (e.g., X2) interface 806 with a 5G radio network node (e.g., gNB) 100; 200.

When it comes to control plane signaling, the 5G radio network node (e.g., gNB) 100; 200 conventionally is not directly connected to any core network (CN), e.g., of the EPC and/or the 4G CN, but only connected via a (e.g., X2) interface 806 to a 4G radio network node (e.g., eNB) 100; 200, e.g., for the sole purpose of performing dual connectivity.

The 5G RAN (NG) architecture of Fig. 8 may be expanded by spitting the centralized unit (e.g., gNB-CU) 810 into two entities, namely one user plane centralized unit (gNB-CU-UP), which serves the user plane and hosts a PDCP protocol and one control plane centralized unit (gNB-CU-CP), which serves the control plane and hosts PDCP and/or RRC protocols. Alternatively or in addition, a distributed unit (e.g., gNB-DU) 912 may host RLC, MAC, and/or PHY protocols.

By the inventive technique, the 5G RAN (or NG-RAN) node configuration update procedure of Sec. 8.4.2 and the cell activation procedure of Sec. 8.4.3 of the 3GPP TS 38.423 V17.0.0 may extended to comprise a request for transmitting RSs without activating the corresponding second radio network node. According to Sec. 8.4.2 of the 3GPP TS 38.423 V17.0.0, the conventional 5G RAN (or NG-RAN) node configuration update procedure allows a radio network node (e.g., a NG-RAN node, e.g., the first radio network node 100) to transmit to a neighboring radio network node (e.g., neighboring NG-RAN node, e.g., a second radio network node 200) an update of configuration information that is essential for the two radio network nodes (e.g., NG-RAN nodes, e.g., first radio network node 100 and second radio network node 200) to interoperate correctly over a (e.g., Xn-C) interface.

The conventional 5G RAN (e.g., NG-RAN) node configuration update procedure uses non-radio device (e.g., non-UE, and/or non-radio device 300)-associated signaling.

Fig. 9A and Fig. 9B show a successful operation and an unsuccessful operation, respectively, of a 5G RAN (or NG-RAN) node configuration update procedure.

In both cases of Fig. 9A and 9B, the first radio network node (e.g., a first NG-RAN node) 100 initiates the procedure by sending a NG-RAN NODE CONFIGURATION UPDATE message 902 to a second radio network node (e.g., a second NG-RAN node) 200. Upon receipt of this message 902, the second radio network node (e.g., the second NG-RAN node) 200 should update the configuration data associated to the first radio network node (e.g., the first NG-RAN node) 100 that it has stored locally. The NG-RAN NODE CONFIGURATION UPDATE message 902 may comprise a list of served 5G (or NR) cells to update, a list of served 4G (or E-UTRA and/or LTE) cells to update, or both, which may comprise a Served Cells NR To Modify Information Element (IE) and Served Cells E-UTRA To Modify IE, respectively.

If a Deactivation Indication IE is comprised in the Served Cells NR To Modify IE, it indicates that the corresponding cell was switched off for network energy saving. Analogously, if the Deactivation Indication IE is comprised in the Served Cells E- UTRA To Modify IE, it indicates that the corresponding cell was switched off for network energy saving.

In the case of a successful operation in Fig. 9A, the second radio network node (e.g., the second NR-RAN node) 200 sends a NG-RAN NODE CONFIGURATION UPDATE ACKNOWLEDGE message 904 to the first radio network node (e.g., the first NG-RAN node) 100. If the second radio network node (e.g., the second NG-RAN node) 200 cannot accept the update, in Fig. 9B it responds with a NG-RAN NODE CONFIGURATION UPDATE FAILURE message 906 and with an appropriate cause value.

According to cell activation procedure of Sec. 8.4.3 of the 3GPP TS 38.423 V17.0.0, the conventional cell activation procedure enables a first radio network node (e.g., NG-RAN node) 100 to request a second radio network node (e.g., neighbouring NG-RAN node) 200 to switch on one or more cells, which have been reported as turned off for network energy saving at an earlier point in time.

The cell activation procedure uses non-radio device (e.g., non-UE, e.g., non-radio device 300)-associated signaling.

As shown in Figs. 10A and 10B, a first radio network node (e.g., a first NG-RAN node) 100 initiates the procedure by sending a CELL ACTIVATION REQUEST message 1002 to a second radio network node (e.g., a second NG-RAN node) 200.

Upon receipt of this message 1002, the second radio network node (e.g., second NG-RAN node) 200 should switch on the one or more cells indicated in the CELL ACTIVATION REQUEST message 1002, and upon successful operation (i.e., successfully switching on the one or more cells afterwards indicate, as depicted in Fig. 10A, in a CELL ACTIVATION RESPONSE message 1004 to the first radio network node (e.g., the first NG-RAN node) 100, for which of the one or more cells the request was fulfilled.

If the second radio network node (e.g., second NG-RAN node) 200 turns on one or more cells upon receipt of a CELL ACTIVATION REQUEST message 1002 from the first radio network node (e.g., first NG-RAN node) 100, and if the second radio network node (e.g., second NG-RAN node) 200 afterwards responds to said request via a CELL ACTIVATION RESPONSE message 1004 as shown in Fig. 10A, the second radio network node (e.g., second NG-RAN node) 200 shall conventionally not send a NG-RAN CONFIGURATION UPDATE message 902 to inform the first radio network node (e.g., first NG-RAN node) 100 about one or more cell activation state changes.

If the second radio network node (e.g., second NG-RAN node) 200 cannot turn on any of the cells indicated in the CELL ACTIVATION REQUEST message 1002 sent by the first radio network node (e.g., first NG-RAN node) 100, as shown in Fig. 10B, the second radio network node (e.g., second NG-RAN node) 200 shall respond with a CELL ACTIVATION FAILURE message 1006 with an appropriate cause value.

The conventional CELL ACTIVATION REQUEST message is defined in Clause 9.1.3.7 of 3GPP TS 38.423 V17.0.0. It is sent by the first radio network node (e.g., NG-RAN node 1) 100 to the second radio network node (e.g., peer NG-RAN node 2) 200 to request one or more previously switched-off cells to be re-activated as follows:

Direction: NG-RAN node 1 -> NG-RAN node 2. When one or more second radio network nodes (e.g., capacity gNBs or cells) are turned off and there is a capacity demand (and/or traffic demand) which the first radio network node (e.g., coverage gNB or cell) cannot serve efficiently and/or not sufficiently on its own, it is necessary to turn on one or more second radio network nodes (e.g., one or more capacity gNBs or cells) 200 again.

Conventionally, there is no sufficient information at the first radio network node (e.g., coverage gNB) 100, to selectively turn on one or more (e.g., the best and/or most suitable one) second radio network nodes 200, but all second radio network nodes (e.g., capacity gNBs or cells) 200 are conventionally turned on (also denoted as woken up). Waking up an inappropriate (e.g., not suitable for serving the existing radio devices 300) second radio network node (e.g., gNB or cell) 200 cannot help to efficiently offload user traffic from the first radio network node (e.g., coverage gNB or cell) 100 and causes a waste of power and/or energy.

In the following, exemplary embodiments of efficiently activating (also denoted as turning on, and/or waking up) one or more second radio network nodes 200 according to the inventive technique are described.

According to a first embodiment, a first radio network node (e.g., first gNB) 100, which is responsible for coverage, requests one or more second radio network nodes (e.g., second gNBs), which are responsible for additional capacity but currently in an energy saving state (e.g., a sleep mode and/or deactivated), to temporarily transmit one or more RSs, e.g., at some specific time instances and/or for some specific time periods.

According to a second embodiment, which is combinable with the first embodiment, one or more of the requested RSs are further specified by the first radio network nodes (e.g., first gNB) 100 to be one or more of all SSBs of the second radio network node (e.g., second gNB) 200, a subset of all SSBs of the second radio network node (e.g., second gNB) 200, and/or one or more CSI-RSs of the second radio network node (e.g., second gNB) 200.

According to a third embodiment, which is combinable with the first and/or second embodiment, the indicated set of RSs may be requested to be transmitted at a certain output power level.

According to a fourth embodiment, which is combinable with any one of the preceding embodiments, the indicated set of SSBs may be specified to be cell defining and/or non-cell defining.

According to a fifth embodiment, which is combinable with any one of the preceding embodiments, in case the indicated set of RSs are cell defining SSBs, the first radio network node (e.g., first gNB) 100 may further request (also: ask), individually for each second radio network node 200, the one or more second radio network nodes (e.g., second gNBs) 200 to operate in a mode in which they do not allow some or any radio devices (e.g., UEs) 300 to camp on the second radio network node (e.g., second gNB) 200 and/or corresponding cell during the RS provisioning period.

According to a sixth embodiment, which is combinable with any one of the preceding embodiments, the first radio network node (e.g., first gNB) 100 may further ask any one of the second radio network nodes (e.g., gNBs) 200 (e.g., independently for each second radio network nodes 200) to transmit the indicated set of RSs on specific time resources and/or specific frequency resources, including whether the transmission is aperiodic (one-shot) or periodic, including a specific time window.

According to a seventh embodiment, which is combinable with any one of the preceding embodiments, the second radio network node (e.g., second gNB) 200 confirms to transmit the indicated set of RS, or alternatively a subset thereof, and/or another set of RSs on the same and/or other time-frequency resources.

According to an eighth embodiment, which is combinable with any one of the preceding embodiments, the first radio network node (e.g., first gNB) 100 informs a radio device (e.g., UE) 300 about what type of resources and on which time-frequency resources the second radio network node (e.g., second gNB) 200 will transmit the one or more RSs, e.g., the first radio network node (e.g., first gNB) 100 configures a radio device (e.g., UE) 300 to measure on the RSs transmitted by the second radio network node (e.g., second gNB) 200.

According to a ninth embodiment, which is combinable with any one of the preceding embodiments, the second radio network node (e.g., second gNB) 200 transmits the agreed set of RSs on the agreed time-frequency resources.

According to a tenth embodiment, which is combinable with any one of the preceding embodiments, the second radio network node (e.g., second gNB) 200 may operate in a mode in which it does not allow some or any radio devices (e.g., UEs) 300 to camp on it while it is providing RSs for the purpose of the inventive technique, e.g., a cell's status may be set to one of 3GPP existing "barred", "reserved for operators", "reserved for other use", or a newly introduced status such as "reference signal provisioning only" or alike. Alternatively or in addition, the cell may not be transmitting essential system information, or similar during this time. Further alternatively or in addition, any cell's status may comprise the energy saving mode.

According to an eleventh embodiment, which is combinable with any one of the preceding embodiments, the radio device (e.g., UE) 300 may be informed (e.g., via a dedicated message, and/or via broadcast information) by the first radio network node (e.g., first gNB) 100 that it is prohibited to camp on the second radio network node (e.g., second gNB) 200, or corresponding cell, for a period of time, e.g., defined and/or specified by a back-off timer, or while the radio link quality measurement (also denoted as RS measurement) is ongoing. Based on this information, the radio device (e.g., UE) 300 refrains from camping and/or accessing the one or more (e.g., second) cells of the second radio network node (e.g., second gNB) 200.

According to a twelfth embodiment, which is combinable with any one of the preceding embodiments, the first radio network node (e.g., first gNB) 100 checks the measurement results and/or reports from all radio devices (e.g., UEs) 300 for one or more different second radio network node (e.g., second gNBs) 200, selects the one or more second radio network nodes (e.g., second gNBs) 200 which can better (or best) take over the traffic and, if necessary, signals to one or more selected second radio network nodes (e.g., gNB) 200 to wake it and/or them up (also denoted as activate it and/or them).

According to a thirteenth embodiment, which is combinable with any one of the preceding embodiments, the first radio network node (e.g., first gNB) 100 stores, and/or by any means remembers, the one or more areas from which the measurement reports from radio devices (e.g., UEs) 300 were received, which RSs from which other radio network nodes (e.g., other gNBs) 200; 100 were contained, and what the characteristics and/or configuration of the RSs were at that point in time (e.g., what type of RSs, output power level, time-frequency resources). Thus, the (in particular first) radio network node (e.g., gNB) 100 may remember the whereabouts of radio device (e.g., UEs) at the time of reporting, the reports' contents and the second radio network nodes' (e.g., second gNBs') 200 RS configurations. According to a fourteenth embodiment, which is combinable with any one of the preceding embodiments, the one or more areas at the time of reporting of the previous embodiment may be identified by a beam of the first radio network node (e.g., first gNB) 100 currently used by a radio device (e.g., UE) 300, and/or a coverage level and/or situation of a radio device (e.g., UE) 300 at the first radio network node (e.g., first gNB) 100, and/or a timing advance (TA) value of the radio device (e.g., UE) 300, and/or an angle of arrival of the report, and/or geographical position (e.g., if a positioning service such as observed time difference of arrival, OTDOA, satellite-based, and/or alike is ongoing) of the radio device (e.g., UE) 300 at the time of report.

According to a fifteenth embodiment, which is combinable with any one of the preceding embodiments, after a certain learning period, the first radio network node (e.g., first gNB) 100, depending on a whereabout of a radio device (e.g., UE) 300, asks only the relevant second radio network node (e.g., second gNBs) 200e.g., those radio network nodes (e.g., gNBs) 200 and/or corresponding cells for which one or more radio devices (e.g., UEs) 300 in the area have previously reported a good signal quality, for RS transmissions. Based on earlier learning, the first radio network node (e.g., first gNB) 100 may potentially ask for specific RSs with specific characteristics (e.g., a specific synchronization signal block, SSB, with specific output power that is good enough for taking over the radio device, e.g., UE 300).

The first to fifteenth embodiments may be performed by one or more radio network nodes of a RAN.

According to a sixteenth embodiment, which is combinable with any one of the preceding embodiments, a radio device (e.g., UE) 300 receives information from the first radio network node (e.g., first gNB) 100 about what type of resources and on which time-frequency resources the second radio network node (e.g., second gNB) 200 will transmit the one or more RSs, e.g., the radio device (e.g., UE) 300 receives a configuration to measure on the RSs transmitted by the second radio network node (e.g., second gNB) 200.

According to a seventeenth embodiment, which is combinable with any one of the preceding embodiments, the radio device (e.g., UE) 300 may also be informed that it is prohibited to camp on any second radio network node (e.g., second gNB) 200 for a period of time, e.g., defined and/or provided by a back-off timer. According to an eighteenth embodiment, which is combinable with any one of the preceding embodiments, the radio device (e.g., UE) 300 performs a radio resource management (RRM) measurement on RSs of one or more second radio network node (e.g., second gNBs) 200 at and/or for the specific time-frequency resources as informed (e.g., configured) by the first radio network node (e.g., first gNB) 100.

According to a nineteenth embodiment, which is combinable with any one of the preceding embodiments, the radio device (e.g., UE) 300 sends back the RRM measurement results to the first radio network node (e.g., first gNB) 100 and may wait for random access (RA) and/or handover chance.

According to a twentieth embodiment, which is combinable with any one of the preceding embodiments, the radio device (e.g., UE) may only send back the RRM measurement result of a second radio network node (e.g., second gNB) 200 that provides the best signal strength, e.g., RSRP, RSRQ, SNR, SINR or similar, to save uplink (UL) resources. Alternatively or in addition, the UE may only report RRM measurement results of those one or more second radio network nodes (e.g., second gNBs) 200 that provide at least a certain signal strength (e.g. as previously indicated by the first radio network node, e.g., first gNB, 100).

According to a twenty-first embodiment, which is combinable with any one of the preceding embodiments, the radio device (e.g., UE) 300 refrains from camping on the second radio network node (e.g., gNB) 200, and/or corresponding cell, for the period of time, e.g., defined and/or specified by a back-off timer, and/or while the radio link quality measurement (also denoted as RS measurement) is ongoing. The radio device (e.g., UE) 300 may do this based on specific information provided to it from the first radio network node (e.g., first gNB) 100 in a dedicated and/or broadcast message, and/or based on a broadcast message from the second radio network node (e.g., second gNB) 200, e.g., comprising a cell status of the second radio network node (e.g., second gNB) 200 set to "reference signal provisioning only" or alike.

The sixteenth to twenty-first embodiments may be performed by one or more radio devices.

An advantage of the inventive technique is that it allows a (e.g., first) radio network node (also denoted as RAN node, e.g., gNB) to know the potential coverage situation after one or more neighboring (e.g., second) radio network nodes (e.g., gNBs) and/or (e.g., partial, in particular only for RS transmission) cell activations without activating the neighboring (e.g., second) radio network nodes (e.g., cells and/or gNBs) for user traffic. Thus, it allows a (e.g., first) radio network node (e.g., gNB) to foresee the network state including the signal conditions and wake up (and/or fully activate) only the needed and most suitable one or more neighbor (e.g., second) radio network nodes (e.g., gNBs) according to traffic demands. Thereby, unnecessary power (and/or energy) consumption and signaling for both the network and the one or more radio devices (e.g., UEs) may be avoided, e.g., due to ineffective cell and/or (e.g., second) radio network node (e.g., gNB) wakeups and consequent ping-pong handovers.

In a heterogeneous network, such as the network 700 in Fig. 7, where there is one (e.g., first) radio network node (e.g., gNB) 100 and/or cell which provides basic coverage and one or more other (e.g., second) radio network nodes (e.g., gNBs) 200 and/or cells which provide capacity boosting, when there is less/little user traffic to serve, to save power, one or multiple capacity boosting (e.g., second) radio network nodes (e.g., gNBs) 200 and/or cells may be turned off. Later, when traffic demand increases such that the first radio network node (e.g., coverage gNB) 100 and/or cell cannot serve adequately, it becomes necessary to turn on one or more second radio network nodes (e.g., capacity gNBs) 200 and/or cells. However, according to the conventional technique it is difficult for the first radio network node (e.g., coverage gNB) 100 to determine which second radio network node (e.g., capacity gNB) 200 and/or cell to turn on as it does not have (e.g., not enough) useful information to make such decision. According to the conventional technique, typically all second radio network nodes (e.g., capacity gNBs) 200 and/or cells will be turned on. This is not a smart decision, as it may be unnecessary to turn on some of the second radio network nodes (e.g., capacity gNBs) 200 and/or cells. This is partly due to the fact that the second radio network nodes (e.g., capacity gNBs) 200 and/or cells, that were not optimal for taking over user traffic, will waste power (and/or energy), and partly due to the fact that radio devices (e.g., UEs) 300 may start camping on, and/or connecting to, these second radio network nodes (e.g., capacity gNBs) 200 and/or cells once they are turned on due to better coverage, resulting in excessive signaling for handing back said radio devices (e.g., UEs) 200 to the first radio network node (e.g., coverage gNB) 100 and/or cell before the second radio network nodes (e.g., capacity gNBs) 200 and/or cells can be turned off again.

According to the inventive technique, one or more second radio network node (e.g., capacity gNB) 200 is allowed to temporarily transmit one or more RSs, e.g., in certain cells, so that one or more radio devices (e.g., UEs) 300 have the chance to measure a radio link quality toward it/them and report the results to the first radio network node (e.g., coverage gNB) 100. Either the first radio network node (e.g., coverage gNB) 100 requests one or more second radio network nodes (e.g., capacity gNBs) 200 to transmit one or more RSs at some specific time and/or for some specific period, or one or more second radio network node (e.g., capacity gNBs) 200 itself/themselves randomly, and/or based on some formula (e.g., based on radio network node, e.g., gNB 100 identity), determine to transmit one or more RSs at some time and/or for some period and inform the first radio network node (e.g., coverage gNB) 100 about the decision in advance.

According to one or more embodiments, there is a coordination between the first radio network node (e.g., coverage gNB) 100 and the second radio network node (e.g., capacity gNB) 200 regarding the RSs to be transmitted, including which type (e.g., SSB, CSI-RS, and/or a newly defined and/or dedicated RS), how many, at what rate, at what time, and/or for which period, at what output power level, and/or on which frequency resources.

Fig. 11 shows an exemplary flowchart of the three methods 400, 500 and 600 for a RAN comprising a first radio network node (e.g., gNBl) 100 and two second radio network nodes (e.g., gNB2 and gNB3) 200 as well as two radio devices (e.g., UE1 and UE2) 300.

The coordination may, e.g., comprise the request 404; 504 and acknowledgement 406; 506 signaling between the first network node 100 and any one of the second network nodes 200 in Fig. 11.

Once it is clear when one or more second radio network nodes (e.g., capacity gNBs) 200 will send one or more RSs, the first radio network node (e.g., coverage gNB) 100 will notify one or more radio devices (e.g., UEs) 300 with this information (e.g., what to expect and/or measure on, when, and/or on which resources). The notification may be in radio device (e.g., UE)-specific signaling, and/or in broadcast signaling. Alternatively or in addition, the timing to transmit one or more RSs from multiple second radio network nodes (e.g., capacity gNBs) 200 may be coordinated, e.g., so that they transmit in adjacent time slots so that there will be no interference between each other, and/or the overall measurement duration for one or more radio devices (e.g., UEs) 300 is optimized (e.g., minimized) to save radio device (e.g., UE) energy (and/or power).

The type of RS may comprise a new (or novel) and/or dedicated type, e.g., a capacity cell CSI-RS (CC-CSI-RS). The radio device (e.g., UE) 300 may be configured with this RS, and/or any conventional RS, through RRC signaling, and/or system information (e.g., SI) broadcast. E.g., an existing system information block (SIB), and/or a new SIB, or RRC signaling in a coverage cell (e.g., defined by the first radio network node 100) may be used to indicate to the radio device (e.g., UE) 300 the presence of one or more capacity cells (e.g., defined by one or more second radio network nodes 200) in its coverage area, and optionally provide the configuration of one or more potential CC-CSI-RSs, or any other type of capacity cell RSs, to the radio device (e.g., UE) 300. According to an exemplary embodiment, the CC-CSI-RS may be designed in an analogous way as the conventional CSI-RS.

With the above information, the radio device (e.g., UE) 300 may perform measurements on one or more neighboring second radio network nodes (e.g., capacity cells) 200 at the specified one or more times, e.g., without needing to search the RSs from the one or more second radio network nodes (e.g., capacity cells) 200 blindly.

According to an embodiment, the radio device (e.g., UE) 300 reports the measurement results for different second radio network nodes (e.g., capacity gNBs) 200 and/or cells to the first radio network node (e.g., coverage gNB) 100.

The measurement results may be reported separately, and/or multiplexed in a single transmission.

With this information, e.g., comprising one or more measurement results, it is clear to the first radio network node (e.g., coverage gNB) 100, which one or more second radio network nodes (e.g., capacity gNBs) 200 and/or cells are more (or most) useful to offload user traffic than others. Then first radio network node (e.g., coverage gNB) 100 may request and/or trigger the one or more second radio network nodes (e.g., capacity gNBs) 200 to re-activate and/or wake up the corresponding cells, e.g., to transition to and/or in normal mode.

According to another embodiment, the report from the radio device (e.g., UE)

300 (e.g., to the first radio network node 100, e.g., coverage gNB, and/or to an associated second radio network node 200, e.g., capacity gNB) may comprise all the measurement results from the RSs the radio device (e.g., UE) 300 is configured with.

According to yet another embodiment, the radio device (e.g., UE) 300 may report only a subset of the collected measurement results. For example, the radio device (e.g., UE) 300 may be configured to report only the measurement results corresponding to the X (with X a natural number, e.g., one to three) best second radio network nodes 200 and/or capacity cells (e.g., having the highest signal strength in terms of RSRP, RSRQ, SNR, and/or SINR) from Y (with Y a natural number, e.g., two to five) second radio network nodes (e.g., capacity gNBs) 200.

According to still another embodiment, the radio device (e.g., UE) 300 may be configured to report only those measurement results that meet one or more predetermined criteria, e.g., if a signal strength is above a predetermined threshold.

In some cases, there may be multiple radio devices (e.g., UEs) 300 that were configured to perform and report such second radio network node (e.g., capacity cell) measurements, and it may happen that, e.g., a first radio device (UE) 300 prefers a first one of the second radio network nodes (e.g., a first capacity cell) 200, while a second radio device (UE) 300 and/or a third radio device (e.g., UE) 300 prefer a second one of the second radio network nodes (e.g., a second capacity cell) 300 (e.g., due to better coverage). In this case, the first radio network node (e.g., coverage gNB) 100 may decide to only turn on and/or request activation of the second one of the second radio network nodes (e.g., the second capacity cell) 200 if all three radio devices (e.g., UEs) 300 can be served by the second one of the second radio network nodes (e.g., the capacity cell) 200, and/or the first radio device (e.g., UE) 300 may remain to be served by the first radio network node (e.g., coverage cell) 100, to avoid turning on and/or requesting activation of both second radio network nodes (e.g., both capacity cells) 200.

The flow chart in Fig. 11 shows an example where, after two radio devices (e.g., UE1 and UE2) 300 performing measurements on two second radio network nodes (e.g., gNB2 and gNB3) 200, the first radio network node (e.g., gNBl) 100 only wakes up (and/or activates) one of the second radio network nodes (e.g., gNB2) 200. When turned on, radio network nodes (e.g., gNBs) typically transmit multiple RSs in various directions. For example, a radio network node (e.g., gNB) may be configured to transmit multiple SSB beams (e.g., up to eight, 8, in frequency range 1, FR1), covering different areas of a cell. However, not all these beam transmissions may be necessary for a specific radio device (e.g., UE) involved in the measurements for the purpose of the inventive technique.

According to an embodiment, the first radio network node (e.g., first gNB) 100 may ask for specific RSs (e.g., specific SSBs or CSI-RSs in specific beams) to be transmitted at a specific time and/or for a specific period. The first radio network node (e.g., first gNB) 100 may have knowledge of which specific RSs, e.g., which specific SSBs, are useful based on operations and maintenance (O&M) manual configurations and/or, more optimally and/or automated, based on an earlier learning process. The learning process may, e.g., be based on that the first radio network node (e.g., first gNB and/or coverage gNB) 100 stores, and/or by any means remembers, the areas from which the measurement reports from radio devices (e.g., UEs) 300 were received, what RSs from which other radio network nodes (e.g., gNBs) were contained, and/or what the characteristics and/or configuration of the RSs were at that point in time, e.g., what type of one or more RS was or were configured, at what output power level, and/or on which timefrequency resources. Thus, the first radio network node (e.g., first gNB) 100 may remember the whereabouts of radio devices (e.g., UEs) 300 at the time of reporting, the reports' contents as well as the second radio network nodes' (e.g., gNBs') RS configurations. The area, in which the measurement report was received at the time of reporting, may be identified, e.g., by a beam of the first radio network node (e.g., first gNB) 100 currently used by the radio device (e.g., UE) 300 (e.g. by means of a precoding matrix index, PMI, and/or SSB), and/or a coverage level of the radio device (e.g., UE) within a cell and/or beam of the first radio network node (e.g., first gNB) 100, and/or a timing advance (TA) value of the radio device (e.g. UE) 300, and/or an angle of arrival of the report, and/or a geographical position (e.g., if a positioning service such as OTDOA, satellite-based, or alike, is ongoing) of the radio device (e.g., UE) 300 at the time of report.

The first radio network node (e.g., first gNB) 100 may check the measurement results and/or reports from all radio devices (e.g., UEs) 300 for different further second radio network nodes (e.g., second/third/... gNBs) 200, select the one or more different further second radio network nodes (e.g., second/third/... gNBs) 200 which can better (or best) take over the one or more radio devices (e.g., UEs) 300 and associated user traffic. After a certain period of such learning, the first radio network node (e.g., first gNB) 100, depending on a whereabout of a radio device (e.g., UE) 300, asks only the relevant further second radio network nodes (e.g., second/third/... gNBs) 200, e.g., those further second radio network nodes (e.g., gNBs) 200 and/or corresponding cells for which one or more radio devices (e.g., UEs) 300 in the area have previously reported a good signal quality, for RS transmissions.

Based on earlier learning, the first radio network node (e.g., first gNB) 100 may potentially ask for specific RSs with specific characteristics (e.g., a specific SSB with specific output power that is good enough for taking over the one or more radio devices 100, e.g., UEs, and associated traffic). It shall be understood that such learning process can be ongoing every now and then to make sure that the knowledge of the first radio network node (e.g., first gNB) 100 is up to date. For example, once a week, the first radio network node (e.g., first gNB) 100 may ask for transmission of all RSs in all neighboring cells at the highest output power level and update the earlier learning based on the newly received radio devicxe (e.g., UE) measurement reports. In summary, the first radio network node (e.g., first gNB) 100 may ask one or more second radio network nodes (e.g., second/third/... gNBs) 200 to transmit one or more SSBs of the second radio network nodes (e.g., second/third/... gNBs) 200, a subset of SSBs of the second radio network nodes (e.g., second/third/... gNBs) 200, and/or one or more CSI-RSs of the second radio network nodes (e.g., second/third/... gNBs) 200.

During the RS provisioning and/or transmission period, the radio devices (e.g., UEs) 300 may start camping on, and/or connecting to, the RS-providing second radio network nodes (e.g., gNBs) 200 and/or their cells once those second radio network nodes (e.g., gNBs) 200 and/or cells are turned on temporarily due to the better perceived coverage, resulting in excessive signaling for handing back said radio devices (e.g., UEs) 300 to the first radio network node (e.g., coverage gNB) 100 and/or cell before the those second radio network nodes (e.g., capacity gNBs) 200 and/or cells can be turned off again. To remedy this issue, according to an embodiment of the inventive technique, it is desired to make those second radio network node (e.g., second gNB) 200 "non-campable" during the RS provisioning and/or transmission period.

According to an embodiment, the set of SSBs may be specified to be non-cell defining, e.g., so that they are not detected by idle and/or inactive mode radio devices (e.g., UEs) 300 for camping (e.g., by not being provided on the sync raster, and/or not containing a remaining minimum SI, RMSI configuration). In one embodiment, the transmissions of "non-campable" RSs may be requested by the first radio network node (e.g., first gNB) 100 over interfaces 806, e.g., Xn interfaces according to NR. In another embodiment, the transmission of "non- campable" RSs is a choice of the second radio network node (e.g., second gNB) 200, and/or is pre-specified, e.g., in a technical specification. In yet another embodiment, even though "campable" RSs (e.g., cell defining SSBs) are transmitted, the second radio network node (e.g., second gNB) 200 may operate in a mode in which it does not allow all and/or some radio devices (e.g., UEs) 300 to camp on that second radio network node (e.g., second gNB) 200 during the RS provisioning and/or transmission period. This can be achieved in one or more ways including not transmitting essential system information (e.g., master information block, MIB, SI Bl, or alike), and/or transmitting essential system information but setting the cell status in system information (SI) to one of the 3GPP existing statuses, e.g., "barred", "reserved for operator use", "reserved for other use", "reserved for future use", and/or a newly introduced (and/or dedicated) status such as "reference signal provisioning only" or alike. Similarly, this behavior may be requested by a first radio network node (e.g., first gNB) 100, and/or decided by a second radio network node (e.g., second gNB) 200, and/or pre-specified, e.g., in a technical specification. As such, the radio device (e.g., UE) 300 refrains from camping on the second radio network node (e.g., second gNB) 200, and/or corresponding cell, for the period of time, e.g., defined and/or specified by a backoff timer, or while the radio link quality measurement (also denoted as RS measurement) is ongoing. The radio device (e.g., UE) 300 may do this either based on specific information provided to it from the first radio network node (e.g., first gNB) 100 in a dedicated and/or broadcast message, and/or based on broadcast message from the second radio network node (e.g., second gNB) 200, e.g., cell status of the second radio network node (e.g., second gNB) 200 set to "reference signal provisioning only" or alike.

Regarding waking up the second radio network nodes (e.g., second/third/... gNBs) 200, according to some embodiments, the first radio network node (e.g., first gNB) 100 may wake up those second radio network nodes (e.g., second/third/... gNBs) 200, and/or their specific cells and/or beams that provide the best signal strength to each radio device (e.g., UE) 300, e.g., via a cell activation procedure, e.g., as described in the context of Figs. 10A and 10b. According to an embodiment, the first radio network node (e.g., gNB) 100 may wake up as few as possible second radio network nodes (e.g., second/third/... gNBs) 200 and/or their specific cells or beams on the premise of ensuring that all radio devices (e.g., UEs) 300 may camp normally on, and/or handover to, a second radio network node (e.g., second/third/... gNB) 200, and/or that all radio devices (e.g., UEs) 300 achieve at least a satisfactory quality of service (QoS) and/or quality of experience (QoE), while at the same time saving as much as possible energy (and/or power) consumed by the network. For example, a radio device (e.g., UE) 300 may have multiple options (e.g., for cell selection, cell reselection and/or handover) when the first radio network node (e.g., first gNB) 100 decides which second radio network nodes (e.g., gNBs) 200 and/or their specific cells and/or beams to wake up, and the first radio network node (e.g., first gNB) 100 may preferentially wake up those second radio network nodes (e.g., second/third/... gNBs) 200 that can serve multiple radio devices (e.g., UEs) 300 rather than those second radio network nodes (e.g., second/third/... gNBs) 200 that can only serve one radio device (e.g., UE) 300.

In another exemplary embodiment, the first radio network node (e.g., gNB) 100, and/or a higher-level entity, may estimate the total power (and/or energy) consumption of different second radio network node (e.g., gNB) 200 and/or cell wake-up and/or activation plans (e.g., either by itself or by means of suitable communication and/or coordination with neighbor radio network nodes, e.g., gNBs) and choose the most energy (and/or power) saving plan to perform.

In an exemplary embodiment, the first radio network node (e.g., coverage gNB) 100 may configure the radio device (e.g., UE) 300 with a measurement configuration related to at least one capacity cell RS, e.g., CC-SI-RS. The reporting may be as in the case of the conventional CSI report, e.g., aperiodic, periodic, and/or semi-persistent. Periodic reporting may be configured, e.g., through RRC signaling and/or SI broadcast, and then the radio device (e.g., UE) 300 measures and reports the capacity cell RSs on a periodic basis. The same holds for semi- persistent, except that MAC control element (MAC CE) and/or downlink control information (DCI) based mechanisms may be used to start and/or stop the periodic reporting in one or more second radio network nodes (e.g., capacity cells) 200.

Alternatively or in addition, lower layer signaling such as DCI signaling may be used to trigger an aperiodic report on capacity cell RSs. In this case, the DCI mechanism may additionally determine the resources over which the report should be done and/or determine if the radio device (e.g., UE) 300 should measure capacity cell RSs of one or more second radio network nodes (e.g., capacity cells) 200.

The technique disclosed herein enables a radio network node (also denoted as RAN node, e.g., gNB) 100 to request another radio network node (also denoted as another RAN node, e.g., another gNB) 200 to transmit one or more RSs, e.g., CSI-RS, and/or SSB, temporarily at a specified time, and/or for a specified period. For this, the radio network node (e.g., RAN node) 100 may reuse the cell activation procedure and the CELL ACTIVATION REQUEST message 1002 of Figs. 10A and 10B, based on the assumption that the cell activation procedure is enhanced accordingly, and/or a newly defined message not yet standardized. An implementation example of such a new message, which may, e.g., be called REFERENCE SIGNAL TRANSMISSION REQUEST or similar, is provided further below as a possible extension to the current 3GPP TS 38.423 V17.00. If no specific one or more RSs, such as CSI-RS, are indicated by the first radio network node (e.g., first RAN node and/ the first gNB) 100 in the request message, the second radio network node (e.g., second RAN node and/ second gNB) 200 may in one embodiment assume that the transmission of SSBs is requested for the cells and/or SSB beams indicated in the request message.

There may be a need for a coordination point in time for when (e.g., at what time) exactly the one or more second radio network nodes (e.g., second/third/... gNBs) 200 shall initiate the RS transmission. It might, e.g., be important for some use cases that the RSs are transmitted at the same time from all second radio network nodes (e.g., gNBs) 200. In other use cases, it might conversely be important that the RSs from various second radio network nodes (e.g., gNBs) 200 are not overlapping in time. In one embodiment, the initiation time may be requested by the first radio network node (e.g., gNB) 100, e.g., in the REFERENCE SIGNAL TRANSMISSION REQUEST, e.g., "start now", "start in x milliseconds" from now, or similar. In another embodiment, the initiation time may be based on a formula based on the time when REFERENCE SIGNAL TRANSMISSION REQUEST or REFERENCE SIGNAL TRANSMISSION RESPONSE was transmitted and/or received, e.g., specified in terms of a system frame number (SNF).

In another embodiment, the REFERENCE SIGNAL TRANSMISSION REQUEST (e.g., according to steps 404; 504) and/or REFERENCE SIGNAL TRANSMISSION RESPONSE (e.g., according to steps 406; 506) signaling is used as a preparation step and/or procedure toward various second radio network nodes (e.g., gNBs) 200. Based on various responses, the first radio network node (e.g., first gNB) 100 may know which other second radio network nodes (e.g., gNBs) 200 can transmit what RSs, in which cells, and/or when. After gathering such responses, an initiation signal, e.g., REFERENCE SIGNAL TRANSMISSION INITIATE (e.g., according to the steps 408; 508), may be transmitted to the one or more second radio network nodes (e.g., gNBs) 200, whereupon the second radio network nodes (e.g., gNBs) 200 start the previously agreed RS transmission. In a related embodiment, the RS transmission may start immediately after reception of REFERENCE SIGNAL TRANSMISSION INITIATE signal (e.g., according to the steps 408; 508), and/or the signal and/or message may contain a starting time, e.g., an absolute time, a relative time (also denoted as time offset, or briefly: offset) to an event such as reception of the signal and/pr message, and/or a SFN point in time or alike.

In the following, exemplary extensions to the conventional technical standard according to the 3GPP TS 38.423 in its current version V17.0.0 are provided.

(1) REFERENCE SIGNAL TRANSMISSION REQUEST

This message is sent by the NG-RAN node 1 to the peer NG-RAN node 2 to request temporary transmission of reference signal/s in previously switched-off cell/s.

Direction: NG-RAN node 1 -> NG-RAN node 2.

(2) REFERENCE SIGNAL TRANSMISSION RESPONSE This message is sent by an NG-RAN node 2 to a peer NG-RAN node 1 to indicate that reference signal/s will be transmitted temporarily in one or more previously switched-off cells.

Direction: NG-RAN node 2 -> NG-RAN node 1.

(3) REFERENCE SIGNAL TRANSMISSION FAILURE

This message is sent by an NG-RAN node 2 to a peer NG-RAN node 1 to indicate reference signal transmission failure. This applies only to the case where none of the reference signals requested by NG-RAN node 1 will be transmitted by NG- RAN node 2.

Direction: NG-RAN node2 -> NG-RAN nodel.

Fig. 12 shows a schematic block diagram for an embodiment of the device 100. The device 100 comprises processing circuitry, e.g., one or more processors 1204 for performing the method 400 and memory 1206 coupled to the processors 1204.

For example, the memory 1206 may be encoded with instructions that implement at least the module 102, and optionally further the modules 104, 106, 108, 110, 112, 114, 116 and 118.

The one or more processors 1204 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the device 100, such as the memory 1206, transmitter functionality. For example, the one or more processors 1204 may execute instructions stored in the memory 1206. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device being operative to perform an action" may denote the device 100 being configured to perform the action.

As schematically illustrated in Fig. 12, the device 100 may be embodied by a first radio network node 1200. The first radio network node 1200 comprises a radio interface 1202 coupled to the device 100 for radio and/or wired communication with one or more second radio network nodes 200 and/or radio devices 300.

Fig. 13 shows a schematic block diagram for an embodiment of the device 200. The device 200 comprises processing circuitry, e.g., one or more processors 1304 for performing the method 500 and memory 1306 coupled to the processors 1304.

For example, the memory 1306 may be encoded with instructions that implement at least module 204, and optionally further the modules 205, 206, 208, 211 and 216.

The one or more processors 1304 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the device 200, such as the memory 1306, receiver functionality. For example, the one or more processors 1304 may execute instructions stored in the memory 1306. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device being operative to perform an action" may denote the device 200 being configured to perform the action.

As schematically illustrated in Fig. 13, the device 200 may be embodied by a second radio network node 1300. The second radio network node 1300 comprises a radio interface 1302 coupled to the device 200 for radio and/or communication with the first radio network node 100 and/or radio devices 300.

Fig. 14 shows a schematic block diagram for an embodiment of the device 300. The device 300 comprises processing circuitry, e.g., one or more processors 1404 for performing the method 600 and memory 1406 coupled to the processors 1404.

For example, the memory 1406 may be encoded with instructions that implement at least the module 310, and optionally further the modules 311, 312 and 318. The one or more processors 1404 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the device 300, such as the memory 1406, receiver functionality. For example, the one or more processors 1404 may execute instructions stored in the memory 1406. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device being operative to perform an action" may denote the device 300 being configured to perform the action.

As schematically illustrated in Fig. 14, the device 300 may be embodied by a radio device 1300 The radio device 1300 comprises a radio interface 1302 coupled to the device 300 for radio communication with the first radio network node 100, one or more second radio network nodes 200, and/or further radio devices 300 (e.g., on a SL).

With reference to Fig. 15, in accordance with an embodiment, a communication system 1500 includes a telecommunication network 1510, such as a 3GPP-type cellular network, which comprises an access network 1511, such as a radio access network, and a core network 1514. The access network 1511 comprises a plurality of base stations 1512a, 1512b, 1512c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1513a, 1513b, 1513c. Each base station 1512a, 1512b, 1512c is connectable to the core network 1514 over a wired or wireless connection 1515. A first user equipment (UE) 1591 located in coverage area 1513c is configured to wirelessly connect to, or be paged by, the corresponding base station 1512c. A second UE 1592 in coverage area 1513a is wirelessly connectable to the corresponding base station 1512a. While a plurality of UEs 1591, 1592 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1512.

Any of the base stations 1512 may embody the device 100 and/or 200. Alternatively or in addition any one of the UEs 1591, 1592 may embody the device 300. The telecommunication network 1510 is itself connected to a host computer 1530, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 1530 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 1521, 1522 between the telecommunication network 1510 and the host computer 1530 may extend directly from the core network 1514 to the host computer 1530 or may go via an optional intermediate network 1520. The intermediate network 1520 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 1520, if any, may be a backbone network or the Internet; in particular, the intermediate network 1520 may comprise two or more sub-networks (not shown).

The communication system 1500 of Fig. 15 as a whole enables connectivity between one of the connected UEs 1591, 1592 and the host computer 1530. The connectivity may be described as an over-the-top (OTT) connection 1550. The host computer 1530 and the connected UEs 1591, 1592 are configured to communicate data and/or signaling via the OTT connection 1550, using the access network 1511, the core network 1514, any intermediate network 1520 and possible further infrastructure (not shown) as intermediaries. The OTT connection 1550 may be transparent in the sense that the participating communication devices through which the OTT connection 1550 passes are unaware of routing of uplink and downlink communications. For example, a base station 1512 need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 1530 to be forwarded (e.g., handed over) to a connected UE 1591. Similarly, the base station 1512 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1591 towards the host computer 1530.

By virtue of the methods 400 and 500 being performed by base station 1512a, 1512b and/or 1512c, and the method 600 being performed by any one of the UEs 1591 or 1592, the performance or range of the OTT connection 1550 can be improved, e.g., in terms of increased throughput and/or reduced latency. More specifically, the host computer 1530 may indicate to the RAN 700, or a relay radio device 300 or a remote radio device (e.g., on an application layer) the QoS of the traffic. Example implementations, in accordance with an embodiment of the UE, base station and host computer discussed in the preceding paragraphs, will now be described with reference to Fig. 16. In a communication system 1600, a host computer 1610 comprises hardware 1615 including a communication interface 1616 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1600. The host computer 1610 further comprises processing circuitry 1618, which may have storage and/or processing capabilities. In particular, the processing circuitry 1618 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 1610 further comprises software 1611, which is stored in or accessible by the host computer 1610 and executable by the processing circuitry 1618. The software 1611 includes a host application 1612. The host application 1612 may be operable to provide a service to a remote user, such as a UE 1630 connecting via an OTT connection 1650 terminating at the UE 1630 and the host computer 1610. In providing the service to the remote user, the host application 1612 may provide user data, which is transmitted using the OTT connection 1650. The user data may depend on the location of the UE 1630. The user data may comprise auxiliary information or precision advertisements (also: ads) delivered to the UE 1630. The location may be reported by the UE 1630 to the host computer, e.g., using the OTT connection 1650, and/or by the base station 1620, e.g., using a connection 1660.

The communication system 1600 further includes a base station 1620 (e.g., embodying the first radio network node 100; 1200 and/or one or more second radio network nodes 200; 1300) provided in a telecommunication system and comprising hardware 1625 enabling it to communicate with the host computer 1610 and with the UE 1630 (e.g., embodying the radio device 300). The hardware 1625 may include a communication interface 1626 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1600, as well as a radio interface 1627 for setting up and maintaining at least a wireless connection 1670 with a UE 1630 located in a coverage area (not shown in Fig. 16) served by the base station 1620. The communication interface 1626 may be configured to facilitate a connection 1660 to the host computer 1610. The connection 1660 may be direct, or it may pass through a core network (not shown in Fig. 16) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 1625 of the base station 1620 further includes processing circuitry 1628, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 1620 further has software 1621 stored internally or accessible via an external connection.

The communication system 1600 further includes the UE 1630 (e.g., embodying the radio device 300) already referred to. Its hardware 1635 may include a radio interface 1637 configured to set up and maintain a wireless connection 1670 with a base station serving a coverage area in which the UE 1630 is currently located. The hardware 1635 of the UE 1630 further includes processing circuitry 1638, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 1630 further comprises software 1631, which is stored in or accessible by the UE 1630 and executable by the processing circuitry 1638. The software 1631 includes a client application 1632. The client application 1632 may be operable to provide a service to a human or non-human user via the UE 1630, with the support of the host computer 1610. In the host computer 1610, an executing host application 1612 may communicate with the executing client application 1632 via the OTT connection 1650 terminating at the UE 1630 and the host computer 1610. In providing the service to the user, the client application 1632 may receive request data from the host application 1612 and provide user data in response to the request data. The OTT connection 1650 may transfer both the request data and the user data. The client application 1632 may interact with the user to generate the user data that it provides.

It is noted that the host computer 1610, base station 1620 and UE 1630 illustrated in Fig. 16 may be identical to the host computer 1530, one of the base stations 1512a, 1512b, 1512c and one of the UEs 1591, 1592 of Fig. 15, respectively. This is to say, the inner workings of these entities may be as shown in Fig. 16, and, independently, the surrounding network topology may be that of Fig. 15.

In Fig. 16, the OTT connection 1650 has been drawn abstractly to illustrate the communication between the host computer 1610 and the UE 1630 via the base station 1620, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 1630 or from the service provider operating the host computer 1610, or both. While the OTT connection 1650 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 1670 between the UE 1630 and the base station 1620 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 1630 using the OTT connection 1650, in which the wireless connection 1670 forms the last segment. More precisely, the teachings of these embodiments may reduce the latency and improve the data rate and/or capacity, and thereby provide benefits such as better responsiveness and improved QoS.

A measurement procedure (e.g., related to one or more RSs signals transmitted by one or more base stations 1620 embodying second radio network nodes 200; 1300 upon a request by another base station 1620 embodying the first radio network node 100; 1200) may be provided for the purpose of monitoring data rate, latency, QoS and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1650 between the host computer 1610 and UE 1630, in response to variations in the measurement results, e.g., related to one or more RSs signals transmitted by one or more base stations 1620 embodying second radio network nodes 200; 1300. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1650 may be implemented in the software 1611 of the host computer 1610 or in the software 1631 of the UE 1630, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 1650 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 1611, 1631 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1650 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 1620, and it may be unknown or imperceptible to the base station 1620. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer's 1610 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 1611, 1631 causes messages to be transmitted, in particular empty or "dummy" messages, using the OTT connection 1650 while it monitors propagation times, errors etc.

Fig. 17 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station (e.g., embodying the first radio network node 100; 1200 and/or one or more second radio network nodes 200; 1300) and a UE (e.g., embodying the radio device 300) which may be those described with reference to Figs. 15 and 16. For simplicity of the present disclosure, only drawing references to Fig. 17 will be included in this paragraph. In a first step 1710 of the method, the host computer provides user data. In an optional substep 1711 of the first step 1710, the host computer provides the user data by executing a host application. In a second step 1720, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 1730, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth step 1740, the UE executes a client application associated with the host application executed by the host computer.

Fig. 18 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station (e.g., embodying the first radio network node 100; 1200 and/or one or more second radio network nodes 200; 1300) and a UE (e.g., embodying the radio device 300) which may be those described with reference to Figs. 15 and 16. For simplicity of the present disclosure, only drawing references to Fig. 18 will be included in this paragraph. In a first step 1810 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In a second step 1820, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step 1830, the UE receives the user data carried in the transmission.

As has become apparent from above description, at least some embodiments of the technique allow for an improved analysis for a coverage situation, in particular by activating neighbor nodes (also denoted as second radio network nodes) only for transmissions of RSs without activating the neighboring nodes for user traffic.

The inventive technique allows to foresee the network state including the signal conditions and wake up only the needed and/or most suitable neighbor node (e.g., one or more second radio network nodes) according to traffic demands, therefore avoiding unnecessary power (and/or energy) consumption and signaling for both network and radio devices, e.g., due to ineffective cell and/or neighbor node (e.g., one or more second radio network node) wakeups and consequent ping-pong handovers.

Many advantages of the present invention will be fully understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the units and devices without departing from the scope of the invention and/or without sacrificing all of its advantages. Since the invention can be varied in many ways, it will be recognized that the invention should be limited only by the scope of the following claims.