Field

The following exemplary embodiments relate to wireless communication and connections with passive radio devices.

Background

Wireless communication networks, such as cellular communication networks evolve, and may be utilized for various purposes including Internet of Things (loT). The connections used for loT are predicted to increase significantly. As there will be a great amount of devices interconnected, it is beneficial to improve production efficiency and increase comforts of life by for example further reducing size, cost, and power consumption for passive radio device, which may act as loT devices.

Brief Description

The scope of protection sought for various embodiments of the invention is set out by the independent claims. The exemplary embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

According to a first aspect there is provided an apparatus comprising means for: transmitting, to a network element, a request, for obtaining ranging information for a passive radio device, transmitting an activation signal to the passive radio device, obtaining, from the network element, a report comprising first ranging information for the passive radio device, determining second ranging information for the network element, obtaining a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the network element, applying the configuration to the charging signal, and transmitting the so-configured charging signal to the passive radio device. In some example embodiments according to the first aspect, the means comprises at least one processor, and at least one memory, including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the performance of the apparatus.

According to a second aspect there is provided an apparatus comprising at least one processor, and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: transmit, to a network element, a request, for obtaining ranging information for a passive radio device, transmit an activation signal to the passive radio device, obtain, from the network element, a report comprising first ranging information for the passive radio device, determine second ranging information for the network element, obtain a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the network element, apply the configuration to the charging signal, and transmit the so-configured charging signal to the passive radio device.

According to a third aspect there is provided a method comprising: transmitting, to a network element, a request, for obtaining ranging information for a passive radio device, transmitting an activation signal to the passive radio device, obtaining, from the network element, a report comprising first ranging information for the passive radio device, determining second ranging information for the network element, obtaining a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the network element, applying the configuration to the charging signal, and transmitting the so-configured charging signal to the passive radio device. In some example embodiments according to the third aspect, the method is a computer-implemented method.

According to a fourth aspect there is provided a computer program comprising instructions for causing an apparatus to perform at least the following: transmit, to a network element, a request, for obtaining ranging information for a passive radio device, transmit an activation signal to the passive radio device, obtain, from the network element, a report comprising first ranging information for the passive radio device, determine second ranging information for the network element, obtain a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the network element, apply the configuration to the charging signal, and transmit the so- configured charging signal to the passive radio device.

According to a fifth aspect there is provided a computer program comprising instructions stored thereon for performing at least the following: transmitting, to a network element, a request, for obtaining ranging information for a passive radio device, transmitting an activation signal to the passive radio device, obtaining, from the network element, a report comprising first ranging information for the passive radio device, determining second ranging information for the network element, obtaining a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the network element, applying the configuration to the charging signal, and transmitting the so-configured charging signal to the passive radio device.

According to a sixth aspect there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the following: transmit, to a network element, a request, for obtaining ranging information for a passive radio device, transmit an activation signal to the passive radio device, obtain, from the network element, a report comprising first ranging information for the passive radio device, determine second ranging information for the network element, obtain a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the network element, apply the configuration to the charging signal, and transmit the so-configured charging signal to the passive radio device.

According to a seventh aspect there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: transmitting, to a network element, a request, for obtaining ranging information for a passive radio device, transmitting an activation signal to the passive radio device, obtaining, from the network element, a report comprising first ranging information for the passive radio device, determining second ranging information for the network element, obtaining a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the network element, applying the configuration to the charging signal, and transmitting the so-configured charging signal to the passive radio device.

According to an eighth aspect there is provided a computer readable medium comprising program instructions stored thereon for performing at least the following: transmitting, to a network element, a request, for obtaining ranging information for a passive radio device, transmitting an activation signal to the passive radio device, obtaining, from the network element, a report comprising first ranging information for the passive radio device, determining second ranging information for the network element, obtaining a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the network element, applying the configuration to the charging signal, and transmitting the so-configured charging signal to the passive radio device.

According to a ninth aspect there is provided an apparatus comprising means for: receiving, from a network element, a request, for obtaining ranging information for a passive radio device, receiving a signal from the passive radio device, determining first ranging information for the passive radio device from the received signal, and transmitting, to the network element, a report comprising the first ranging information for the passive radio device.

In some example embodiments according to the first aspect, the means comprises at least one processor, and at least one memory, including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the performance of the apparatus.

According to a tenth aspect there is provided an apparatus comprising at least one processor, and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: receive, from a network element, a request, for obtaining ranging information for a passive radio device, receive a signal from the passive radio device, determine first ranging information for the passive radio device from the received signal, and transmit, to the network element, a report comprising the first ranging information for the passive radio device.

According to an eleventh aspect there is provided a method comprising: receiving, from a network element, a request, for obtaining ranging information for a passive radio device, receiving a signal from the passive radio device, determining first ranging information for the passive radio device from the received signal, and transmitting, to the network element, a report comprising the first ranging information for the passive radio device. In some example embodiments according to the eleventh aspect, the method is a computer-implemented method.

According to a twelfth aspect there is provided a computer program comprising instructions for causing an apparatus to perform at least the following: receive, from a network element, a request, for obtaining ranging information for a passive radio device, receive a signal from the passive radio device, determine first ranging information for the passive radio device from the received signal, and transmit, to the network element, a report comprising the first ranging information for the passive radio device.

According to a thirteenth aspect there is provided a computer program comprising instructions stored thereon for performing at least the following: receiving, from a network element, a request, for obtaining ranging information for a passive radio device, receiving a signal from the passive radio device, determining first ranging information for the passive radio device from the received signal, and transmitting, to the network element, a report comprising the first ranging information for the passive radio device.

According to a fourteenth aspect there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the following: receive, from a network element, a request, for obtaining ranging information for a passive radio device, receive a signal from the passive radio device, determine first ranging information for the passive radio device from the received signal, and transmit, to the network element, a report comprising the first ranging information for the passive radio device.

According to a fifteenth aspect there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: receiving, from a network element, a request, for obtaining ranging information for a passive radio device, receiving a signal from the passive radio device, determining first ranging information for the passive radio device from the received signal, and transmitting, to the network element, a report comprising the first ranging information for the passive radio device.

According to a sixteenth aspect there is provided a computer readable medium comprising program instructions stored thereon for performing at least the following: receiving, from a network element, a request, for obtaining ranging information for a passive radio device, receiving a signal from the passive radio device, determining first ranging information for the passive radio device from the received signal, and transmitting, to the network element, a report comprising the first ranging information for the passive radio device.

According to a seventeenth aspect there is provided a system comprising a first network element and a second network element, wherein the system is caused to: transmit, by the first network element to the second network element, a request, for obtaining ranging information for a passive radio device, transmit, by the first network element, an activation signal to the passive radio device, receive, by the second network element, a signal from the passive radio device, determine, by the second network element, first ranging information for the passive radio device from the received signal, transmit, by the second network element to the first network element, a report comprising the first ranging information for the passive radio device, determine, by the first network element, second ranging information for the second network element, obtain, by the first network element, a configuration for a charging signal from the apparatus towards the passive radio device, wherein the configuration is determined based on the first ranging information for the passive radio device and the second ranging information for the second network element, apply, by the first network element, the configuration to the charging signal, and transmit, by the first network element, the so-configured charging signal to the passive radio device. List of Drawings

In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which

FIG. 1 illustrates an example embodiment of a radio access network.

FIG. 2 illustrates an example embodiment of a passive communication between a reader device and a passive radio device.

FIG. 3 illustrates an example embodiment of network elements and a passive radio device.

FIG. 4 and FIG. 5 illustrate example embodiments of signalling charts of tracking a passive radio device.

FIG. 6 and FIG. 7 illustrate example embodiments of an apparatus.

Description of Embodiments

The following embodiments are exemplifying. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

As used in this application, the term ‘circuitry’ refers to all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of circuits and software (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of ‘circuitry’ applies to all uses of this term in this application. As a further example, as used in this application, the term ‘circuitry’ would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and/or firmware. The term ‘circuitry’ would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device. The above-described embodiments of the circuitry may also be considered as embodiments that provide means for carrying out the embodiments of the methods or processes described in this document.

The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chipset (e.g. procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via any suitable means. Additionally, the components of the systems described herein may be rearranged and/or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

Embodiments described herein may be implemented in a communication system, such as in at least one of the following: Global System for Mobile Communications (GSM) or any other second generation cellular communication system, Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE-Advanced, a system based on IEEE 802.11 specifications, a system based on IEEE 802.15 specifications, and/or a fifth generation (5G) mobile or cellular communication system. The embodiments are not, however, restricted to the system given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties.

FIG. 1 depicts examples of simplified system architectures showing some elements and functional entities, all being logical units, whose implementation may differ from what is shown. The connections shown in FIG. 1 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system may comprise also other functions and structures than those shown in FIG. 1. The example of FIG. 1 shows a part of an exemplifying radio access network.

FIG. 1 shows terminal devices 100 and 102 configured to be in a wireless connection on one or more communication channels in a cell with an access node (such as (e/g)NodeB) 104 providing the cell. The access node 104 may also be referred to as a node. The wireless link from a terminal device to a (e/g)NodeB is called uplink or reverse link and the wireless link from the (e/g) NodeB to the terminal device is called downlink or forward link. It should be appreciated that (e/g)NodeBs or their functionalities may be implemented by using any node, host, server or access point etc. entity suitable for such a usage. It is to be noted that although one cell is discussed in this exemplary embodiment, for the sake of simplicity of explanation, multiple cells may be provided by one access node in some exemplary embodiments.

A communication system may comprise more than one (e/g)NodeB in which case the (e/g)NodeBs may also be configured to communicate with one another over links, wired or wireless, designed for the purpose. These links may be used for signalling purposes. The (e/g)NodeB is a computing device configured to control the radio resources of communication system it is coupled to. The (e/g)NodeB may also be referred to as a base station, an access point or any other type of interfacing device including a relay station capable of operating in a wireless environment. The (e/g)NodeB includes or is coupled to transceivers. From the transceivers of the (e/g)NodeB, a connection is provided to an antenna unit that establishes bidirectional radio links to user devices. The antenna unit may comprise a plurality of antennas or antenna elements. The (e/g)NodeB is further connected to core network 110 (CN or next generation core NGC). Depending on the system, the counterpart on the CN side may be a serving gateway (S-GW, routing and forwarding user data packets), packet data network gateway (P-GW), for providing connectivity of terminal devices (UEs) to external packet data networks, or mobile management entity (MME), etc.

The terminal device (also called UE, user equipment, user terminal, user device, etc.) illustrates one type of an apparatus to which resources on the air interface are allocated and assigned, and thus any feature described herein with a terminal device may be implemented with a corresponding apparatus, such as a relay node. An example of such a relay node is a layer 3 relay (self-backhauling relay) towards the base station. Another example of such a relay node is a layer 2 relay. Such a relay node may contain a terminal device part and a Distributed Unit (DU) part. A CU (centralized unit) may coordinate the DU operation via F1AP -interface for example.

The terminal device may refer to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), or an embedded SIM, eSIM, including, but not limited to, the following types of devices: a mobile station (mobile phone), smartphone, personal digital assistant (PDA), handset, device using a wireless modem (alarm or measurement device, etc.), laptop and/or touch screen computer, tablet, game console, notebook, and multimedia device. It should be appreciated that a user device may also be an exclusive or a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. A terminal device may also be a device having capability to operate in Internet of Things (loT) network which is a scenario in which objects are provided with the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction. The terminal device may also utilise cloud. In some applications, a terminal device may comprise a small portable device with radio parts (such as a watch, earphones or eyeglasses) and the computation is carried out in the cloud. The terminal device (or in some embodiments a layer 3 relay node) is configured to perform one or more of user equipment functionalities.

Various techniques described herein may also be applied to a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the implementation and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals.

Additionally, although the apparatuses have been depicted as single entities, different units, processors and/or memory units (not all shown in FIG. 1) may be implemented.

5G enables using multiple input - multiple output (M1M0) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and employing a variety of radio technologies depending on service needs, use cases and/or spectrum available. 5G mobile communications supports a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applications such as (massive) machine-type communications (mMTC), including vehicular safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, namely below 6GHz, cmWave and mmWave, and also being integratable with existing legacy radio access technologies, such as the LTE. Integration with the LTE may be implemented, at least in the early phase, as a system, where macro coverage is provided by the LTE and 5G radio interface access comes from small cells by aggregation to the LTE. In other words, 5G is planned to support both inter-RAT operability (such as LTE-5G) and inter-Rl operability (inter-radio interface operability, such as below 6GHz - cmWave, below 6GHz - cmWave - mmWave). One of the concepts considered to be used in 5G networks is network slicing in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the same infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

The current architecture in LTE networks is fully distributed in the radio and fully centralized in the core network. The low latency applications and services in 5G may require bringing the content close to the radio which may lead to local break out and multi-access edge computing (MEC). 5G enables analytics and knowledge generation to occur at the source of the data. This approach requires leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content in close proximity to cellular subscribers for faster response time. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing also classifiable as local cloud/fog computing and grid/mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and/or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications). The communication system is also able to communicate with other networks, such as a public switched telephone network or the Internet 112, and/or utilise services provided by them. The communication network may also be able to support the usage of cloud services, for example at least part of core network operations may be carried out as a cloud service (this is depicted in FIG. 1 by “cloud” 114). The communication system may also comprise a central control entity, or a like, providing facilities for networks of different operators to cooperate for example in spectrum sharing.

Edge cloud may be brought into radio access network (RAN) by utilizing network function virtualization (NFV) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. Application of cloudRAN architecture enables RAN real time functions being carried out at the RAN side (in a distributed unit, DU 104) and non-real time functions being carried out in a centralized manner (in a centralized unit, CU 108).

It should also be understood that the distribution of labour between core network operations and base station operations may differ from that of the LTE or even be non-existent. Some other technology that may be used includes for example Big Data and all-lP, which may change the way networks are being constructed and managed. 5G (or new radio, NR) networks are being designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be appreciated that MEC can be applied in 4G networks as well.

5G may also utilize satellite communication to enhance or complement the coverage of 5G service, for example by providing backhauling or service availability in areas that do not have terrestrial coverage. Satellite communication may utilise geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, for example, mega-constellations. A satellite 106 comprised in a constellation may carry a gNB, or at least part of the gNB, that create on-ground cells. Alternatively, a satellite 106 may be used to relay signals of one or more cells to the Earth. The on-ground cells may be created through an on-ground relay node 104 or by a gNB located on-ground or in a satellite or part of the gNB may be on a satellite, the DU for example, and part of the gNB may be on the ground, the CU for example. Additionally, or alternatively, high-altitude platform station, HAPS, systems may be utilized.

It is to be noted that the depicted system is an example of a part of a radio access system and the system may comprise a plurality of (e/g)NodeBs, the terminal device may have an access to a plurality of radio cells and the system may comprise also other apparatuses, such as physical layer relay nodes or other network elements, etc. At least one of the (e/g)NodeBs may be a Home(e/g)nodeB. Additionally, in a geographical area of a radio communication system a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which are large cells, usually having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The (e/g)NodeBs of FIG. 1 may provide any kind of these cells. A cellular radio system may be implemented as a multilayer network including several kinds of cells. In some exemplary embodiments, in multilayer networks, one access node provides one kind of a cell or cells, and thus a plurality of (e/g)NodeBs are required to provide such a network structure.

For fulfilling the need for improving the deployment and performance of communication systems, the concept of “plug-and-play” (e/g)NodeBs has been introduced. A network which is able to use “plug-and-play” (e/g)NodeBs, may include, in addition to Home (e/g)NodeBs (H(e/g)nodeBs), a home node B gateway, or HNB-GW (not shown in FIG. 1). A HNB Gateway (HNB-GW), which may be installed within an operator’s network may aggregate traffic from a large number of HNBs back to a core network. Internet of Things (loT) is envisaged to grow rapidly. loT, which may utilize 5G connectivity, may thus comprise devices, such as tags and/or sensors, that may be considered as passive radio devices, which may also be understood as loT devices. These loT devices require power to be able to transmit and/or receive data. The loT devices may consume for example tens or hundreds of milliwatts power during transceiving. Thus, it is beneficial to consider how to optimize power consumption as well as obtaining of power, such that it is possible to achieve the internet of everything, loT devices with ten or even a hundred times lower cost and power consumption. Further, some applications utilizing loT may require loT devices that are batteryless. This may be for example because replacement of battery for some loT devices may be impractical as that would mean tremendous consumption of materials and manpower. Thus, energy harvesting may be utilized to power loT devices for self-sustainable communications. However, for energy harvesting to be useful, the power available for absorbing is to be greater than the power consumed by the loT device for receiving the power available for harvesting.

One option for batteryless loT devices, such as tags, is to utilize radio frequency identification (RFID). In some examples, an RFID tag may have a power consumption as low as 1 microwatt. RFID may utilize envelope detection for downlink data reception and backscatter communication for uplink data transmission. FIG. 2 illustrates an example embodiment of a passive communication between a reader device and a tag 220. The reader device comprises a unit configured to transmit and receive signals. The unit has a transmitter 210 for broadband transmissions and the transmitter 210 is followed by a power amplifier 212 and an antenna 214 that then transmits a carrier wave 215. The tag 220 then has an antenna 222 that receives the carrier wave. The tag 220 then modifies one or more characteristics of the carrier wave. The characteristics may comprise for example amplitude, phase and/or center frequency. The tag 220 may comprise various units with which the modification can be achieved. In this example embodiment, the tag 220 comprises at least the following units: an RF harvester 232 for harvesting electromagnetic energy from an incoming RF signal, a detection unit 234 for detecting the incoming RF signal, a clock 236 for generating a clock signal, and a logic unit 238 for controlling the operation of the tag 220. The signal, after the modification, is then reflected, by the tag 220, as an uplink reflected signal 225. The uplink reflected signal is then received by the antenna 216 of the reader after which the signal is amplified using a low noise amplifier 218 after which the receiver 219 receives the reflected signal. As such, data transmission may be obtained without generating a carrier wave by the tag 220, which reduces required energy demands as well as costs. Yet, this transmission scheme may become challenging if it is to be applied to a scalable network as link budget and capability may not be enough for the scalable network.

A passive radio device, such as a tag or a sensor, may operate in two modes. One mode is an energy harvesting mode in which the radio device collects energy from wireless signals that are transmitted towards the passive radio device on a given spectra. Another mode is a data transfer mode in which the passive radio device may generate a unique signal. The unique signal then carries data specific to the passive radio device such as its ID or data collected by the passive radio device. These two modes may be implemented in a half- or full duplex manner, in other words, sequentially or simultaneously. To support interactions between the passive radio device and 5G network infrastructure, the passive radio device is to obtain sufficient energy to become discoverable in case the passive radio device is not equipped with a power source. Thus, it would be beneficial to enable the passive radio device to be charged via a transmitter connected to a network, such as the 5G network, in an optimal way with regard to maximizing the received power by the passive radio device. To achieve this, a guided charging and tracking approach to a passive radio device discussed below may be utilized.

In a network, such as 5G network, there may be various network elements such as terminal devices, positioning reference units (PRUs), road side units (RSUs), transmission and reception points (TRPs), access nodes such as gNB, etc. A network element may have different roles, such as an activator role or a reader role. If a network element acts as an activator, it then transmits a signal to a passive radio device such that the signal either charges the passive radio device or it activates the passive radio device. The activator may charge the passive radio device during time periods when the passive radio device operates in an energy-harvesting mode. The activator may also trigger the passive radio device to transmit a signal and the signal may carry information that is specific to the passive radio device. It is to be noted though that in order to activate the passive radio device, the passive radio device is to be switched in a data-transfer mode.

If the network element acts as a reader, the network element then listens to and detects and decodes signals from the passive radio device, and the signals may carry information specific to the passive radio device.

An example embodiment of network elements and a passive radio device in which one network elements acts as an activator and the other one acts as a reader is illustrates in FIG. 3. In this example embodiment, the passive radio device is a tag 310, the network elements acting as a reader is a terminal device 312 and the network element acting as an activator is a terminal device 314. However, it is to be noted that in some alternative example embodiments, the activator 314 may be another network element, for example an access node such as an eNB or a gNB, and/or the reader 312 may be another network element as well, for example an access node such as an eNB or a gNB. Both of the terminal devices 312 and 314 establish a sidelink communication to the tag 310 using a Uu-interface. It is to be noted that in some other example embodiments there may be a plurality of tags to which the terminal devices 312 and 314 establish a sidelink communication. The terminal devices 312 and 314 may receive from the network an indication that indicates to which tag(s) the sidelink communication is to be established. Also, the establishment of the communication link may be guided by the network or, alternatively, it may be guided by the terminal device 314 that acts as an activator or by the tag 310. When establishing the communication link, the terminal device 314 may transmit a request for tracking of the tag 310 by transmitting an indication, in a data message, and the indication may comprise a flag for the request. It is to be noted that tracking the tag 310 may also require the tag 310 to be charged. The data message, which may be transmitted to the tag 310 and/or to the terminal device 312, may be transmitted for example through a physical sidelink shared channel (PSSCH) or a physical uplink/downlink shared channel (PU/DSCH), possibly using small data transfer (SDT) procedure.

As part of establishing the communication link, the terminal devices 312 and 314 may agree on a joint coordinate system (JCS). In other words, they align their local coordinates system to a common reference such as geographical North. Additionally, the terminal device 312 may transmit to the terminal device 314 a requirement for a minimum duration of listening, in other words, a time period that the terminal device 312 is to use for scanning all spatial directions. The minimum duration may depend on the number of receive beams the terminal device 312 is using and/or the time- per-beam that the terminal device 312 has configured. The terminal device 314 may also request the terminal device 312 to report on its mobility conditions, for example, to extract and report the coherence time of the channel (Tc) between the terminal device 312 and 314.

The terminal device 314 may activate the tag 310, by transmitting an activation signal to the tag 310, for a period of time that corresponds at least to the time period of listening of the terminal device 312 and a time delay corresponding to a maximum distance between the terminal device 312 and the tag 310. The terminal device 312 receives a signal from the tag 310 at a time instant Tl, decodes it and additionally estimates the direction of arrival (DoA) 336 and the distance 322 to the tag 310. Additionally, the terminal device 312 may estimate the quality Qt of the signal from the tag 310, and the estimation may comprise for example estimating the signal to interference and noise ratio (S1NRJ. The terminal device 312 may also apply one or more receive beams to collect the signal from the tag 310. In such case, the angle 336 may be obtained directly as the receive beam for which the highest tag power has been collected. Alternatively, or additionally, the terminal device 312 may apply any suitable filtering operation, in digital domain, on the received baseband signal and then estimate the most likely DoA 336.

The terminal device 312 then transmits to the terminal device 314 ranging information Rt = (angle 336, distance 322, Qt, Tl)(tagJD) for the tag 310. The ranging information Rt may be transmitted using PSSCH or PU/DSCH. Additionally, the terminal device 312 may append the coherence time Tc of the channel between the terminal device 312 and the terminal device 314. It is to be noted that the channel coherence time Tc may be estimated using any suitable reference signal, such as demodulation reference signal (DMRS), or channel state information - reference signal (CS1-RS), or positioning reference signal (PRS), transmitted by the terminal device 314.

The terminal device 314 then receives a SL/UL/DL signal from the terminal device 312 at a time instant T2, which comprises the ranging information Rt for the tag 310 and possibly the channel coherence time Tc, and based on the received signal, determines a DoA 334 towards the terminal device 312, a distance 324 to the terminal device 312, and a signal quality Qr. The ranging information Rr for the terminal device 312 may then be determined to be Rr = (angle 334, distance 324, Qr, T2)(readerJD).

The terminal device 314 uses the ranging information Rt and Rr to determine a configuration for a charging signal from the terminal device 314 towards the tag 310. Determining the configuration for the charging signal may comprise for example determining the optimal direction of departure (DoD) 332 from the terminal device 314 towards the tag 310. It is to be noted that there may be additional terminal devices acting as readers such that ranging information Rt and Rr may be determined for these additional terminal devices as well. The DoD 332 may be determined for example by solving (sintanqle 332+anqle 336) . „ „ „ „ „

- - - - - angle DoD 332. Thus, distance 324 ° an approximation of the DoD 332 may be obtained. The terminal device 314 then uses the channel coherence time Tc and the time difference T2-T1 to determine if a previously obtained approximation applies. In other words, the terminal device 314 ensures that the location of the terminal device 312 is at least substantially the same at the time instant T1 when the tag 310 is read by the terminal device 312, and at the time instant T2 when the report is transmitted to the terminal device 314. The locations may be determined to be at least substantially the same if the difference between the locations at the time instants T1 and T2 is less than a pre-determined value.

The terminal device 314 uses the DoD 332 to point its next charging signal towards the tag 310. The terminal device 314 may store the ranging information (Rt, Rr) in a table for tracking the tag 310, and it may also track the location of the tag 310 and determine a displacement of the tag 310 such as displacement relative to a past location of the tag 310, relative to a location of the terminal device 312 or relative to a location of the terminal device 314.

Additionally, or alternatively, the terminal device 314 may report the displacement of the tag 310 back to the network. It is to be noted that in some alternative example embodiments, the DoD 332 may be determined by a location management function LMF, which may also be understood as a network element, and the determined DoD 332 may then be communicated to the terminal device 314, in other words, the terminal device 314 may obtain the DoD 332 from the LMF. In such example embodiment, the terminal device 314 transfers Rt and Rr to the LMF using an information element (IE) in LTE positioning protocol (LPP) and the LMF may then provide the determined DoD 332 using another IE comprised in LPP assistance data.

By having network elements such that at least one acts as a reader and one as an activator, the network elements may establish a strategy for discovering one or more passive radio devices, such as passive loT tags, charge the one or more passive radio devices using a signal that may be understood as a guided signal, and track the one or more passive radio devices in an absolute, or in a relative, manner, depending on whether the activator/reader pairs have known locations.

FIG. 4 illustrates a signalling chart according to an example embodiment of tracking a passive radio device. In this example embodiment, there is a network element, for example an access node, that is an activator 410 and another network element, for example, a terminal device, that is a reader 412. It is to be noted though that although one reader is illustrated in FIG. 4, there may be more than one reader communicating with the activator 410 and detecting passive radio devices. The passive radio device in this example embodiment is a tag 414, although it is to be noted that there could be more passive radio devices as well. The network, such as a 5G network, is also illustrated as 416.

In this example embodiment, the activator 410 is a consumer for ranging information Rt of the tag 414. Thus, the activator 410 may indicate to the reader 412 which passive radio devices are to be detected, by the reader 412, and for which passive radio devices to determine Rt. In this example embodiment, the tag 414 is comprised among those passive radio devices.

The activator 410 transmits 420 to the reader 412 a configuration for the tag 414 and the configuration may comprise for example ID, tag code signature, and/or occupied resources. The configuration for the tag 414 may be transmitted via PSSCH, in case the activator and the reader operate using sidelink, which may be the case for example if both are terminal device. Alternatively, the configuration for the tag 414 may be transmitted using PDSCH in case the activator 410 resides in the network. If the activator 410 resides in a terminal device, then the activator 410 and the reader 412 may receive the configuration for the tag 310 directly from the network.

The activator 410 then transmits 422 to the reader 412 a request for obtaining ranging information, Rt, for the tag 414. It is to be noted that the request may also be for a subset of a plurality of tags and the tag 414 may be comprised in the subset of tags and that the request may, optionally, be transmitted to other network elements acting as readers as well. After this, the activator 414 configures 424 an interface towards the reader 412 for reporting the Rt. The configuring may comprise a configuration for time intervals during which the reader 412 is to listen for the tag 414, and the resources for reporting Rt of the tag 414 back to the activator 414. Reporting of the Rt may be performed for example using PSSCH if the activator 410 and the reader 412 pair operate in sidelink, PUSCH if the activator 410 resides in the network and the reader 412 resides in a terminal device, or PDSCH if the activator 410 resides in a terminal device and the reader 412 resides in the network.

Next, the activator 410 transmits 426 an activation signal to the tag 414. The tag 414 then, as a response, transmits 428 a signal that is specific to the tag 414 to the reader 412. The reader 412 then, in block 430, detects the tag 414 and determines the Rt for the tag 414. It is to be noted that in case there are more than one tag to be detected, the reader 412 may detect those as well and determine their respective Rts as well. After this, the reader 412 transmits 435 the determined Rt to the activator 412.

Then, in block 440, the activator 410 obtains ranging information Rt for the tag 414 from the reader 412, and in block 442 determines ranging information Rr for the reader 412. The determination of the ranging information Rr may be done for example based on the received transmission 435. If the activator 410 and the reader 412 reside in a terminal device and use sidelink for communication, then the ranging information Rt may be carried through PSSCH, while the DMRS of the SL transmission (or any other suitable SL reference signal) may be used by the activator 410 to estimate the ranging information Rr. If the activator 410 resides in the network, then the ranging information Rt may be carried through PUSCH, for instance by means of UL SDT in case the reader is in a radio resource control (RRC) inactive state, while the DMRS of the UL transmission (or any other suitable UL reference signal) may be used for estimation of the ranging information Rr. If the activator 410 resides in the terminal device, and the reader 412 resides in the network, then the ranging information Rt may be carried through PDSCH, for instance by means of DL SDT if the activator 410 is in an RRC inactive state. Similarly, the DMRS of the DL transmission (or any other suitable DL reference signal) may be utilized to estimate the ranging information Rr. In case both the activator 410 and the reader 412 reside in the network, then a backhaul interface, such as an Xn interface, may be used.

In block 444, the activator 410 then determines a DoD towards the tag 414. The DoD may be understood as the optimal DoD. The determination of the DoD may be based on available pair, or pairs, of Rr and Rt for the tag 414. In case there are more than one reader, the (Rr, Rt) pair(s) are 'determined from all the readers. The activator 410 may then check which readers have provided reports that are to be used and which reports to discard due to loss of channel coherency, in other words, ensure that the reader has not moved after it has measured the tag and before it sent the report Rt. The activator 410 may then prioritize ranging information (Rr, Rt) from readers with good channel quality towards the tag 414 and/or towards the activator 410, i.e. check if Qr and/or Qt is above a certain threshold. The activator 410 may then use an available solver of choice and the selected readers indexed l,...,Kto solve for the DoD a multi-lateration problem as follows: where G is the DoD, A is DoA from the reader, B is the DoA from the tag to the reader, d is the distance between the activator and the reader, and a is the distance between the tag and the reader, e ₁₍ ... , e _K are the measurement errors associated with the K readers.

Next, in block 446, the activator 410 generates a precoded signal that is pointed at the tag 414, that is to say the activator 410 concentrates the radiated electromagnetic energy towards the tag 414 for more efficient charging of the tag 414. The precoding may be realized in the analogue, digital or hybrid domain, depending on the activator capability. The precoded charging signal is then transmitted 450 by the activator 410 to the tag 414. After this, the activator 410 stores the DoD, Rt and Rr.

The storing may use a table such as table 1 below:

Table 1

The activator 410 may use the table as well as any available tracking mechanism of choice, such as Kalman-filter, to estimate, in block 455, a change in position, which may be referred to as displacement, of the tag 414 compared to a fixed reference of the location of the activator 410 and/or the location of the reader 412. Alternatively, the displacement may be estimated by comparing to a relative reference such as a past tag position. Optionally, the activator 410 may then transfer 460 the computed tag displacement to the network 416. The transfer 460 may be done for example via backhaul if the activator 410 resides in a gNB or in a TRP, or via UL PUSCH if the activator 410 resides in a terminal device.

FIG. 5 illustrates a signaling chart according to another example embodiment, which is a variation of the example embodiment illustrated in FIG. 4. In this example embodiment, the activator 410 transmits 420 the configuration for the tag 414 to the reader 412 like in the example embodiment of FIG. 4. The activator 410 then, like in the example embodiment of FIG. 4, transmits 422 a request for obtaining ranging information Rt for the tag 414, and it also transmits 424 a configuration for reporting the ranging information Rt to the reader 412. After this, the activator 410 transmits 426 the activation signal to the tag 414, and the tag 414 then transmits 428 the signal specific to the tag 414 to the reader 412 like in the example embodiment of FIG. 4. Block 430, in which the reader 412 detects the tag 414, determines the ranging information Rt, and then transmits 435 the ranging information Rt to the activator 410 are also like in the example embodiment of FIG. 4. The activator 410, then, like in the example embodiment of FIG. 4, in block 440 decodes the payload and retrieves the ranging information Rt, and in block 442 estimates the ranging information Rr for the reader 412.

As a modification to the example of FIG. 4, the activator 410 then transmits 520 the Rt, Rr pair for the tag 414 to an LMF 518 comprised in the network. It is to be noted that additionally, there may be more (Rt, Rr) pairs for more tags or more readers such that an (Rt, Rr) pair is associated with one tag and one reader. The LMF 518 then, in block 522, determines a DoD towards the tag 414. The DoD may be understood as the optimal DoD. The determination of the DoD may be based on the available pair, or pairs, of Rr and Rt for the tag 414. In case there are more than one reader, the Rr, Rt pair(s) are determined from all the readers. The LMF 518 may then check which readers have provided reports that are to be used, and which reports to discard due to loss of channel coherency, in other words, ensure that the reader has not moved after it has measured the tag and before it sent the report Rt. The LMF 518 may then prioritize ranging information (Rr, Rt) from readers with good channel quality, towards the tag 414 and/or towards the activator 410 i.e. check if Qr and/or Qt is above a certain threshold. The LMF 518 may then use an available solver of choice and the selected readers indexed l,...,Kto solve for the DoD a multi-lateration problem as follows: rsin(G + Bj) sinCAi — G)

+ ^e = 0 no+ ^e K - 0 d-K where G is the DoD, A is DoA from the reader, B is the DoA from the tag to the reader, d is the distance between the activator and the reader and a is the distance between the tag and the reader, e ₁₍ ... , e _K are the measurement errors associated with the K readers.

Next, the LMF 518 estimate, in block 524, a change in position, which may be referred to as displacement, of the tag 414 compared to a fixed reference of the location of the activator 410 and/or the location of the reader 412. Alternatively, the displacement may be estimated by comparing to a relative reference such as a past tag position. The 518 may then transfer 526 the computed tag displacement the network 416. The LMF 518 may then transmit 528 information regarding the DoD to the activator 410. The Activator 410 may then, in block 530, generate a precoded charging signal that is pointed at the tag 414 in accordance with the DoD angle indicated by the LMF, and then transmit 535 the charging signal towards the tag 414.

The example embodiments described above may have benefits such as enabling guided charging of the tag i.e., maximizing the received power at the tag to optimize the energy-harvesting performing relative localization of a passive radio device by using an optimum set of active devices.

FIG. 6 illustrates an apparatus 600, which may be an apparatus such as, or comprised in, a terminal device, according to an example embodiment, and that may embody the activator or the reader as described above. The apparatus 600 comprises a processor 610. The processor 610 interprets computer program instructions and processes data. The processor 610 may comprise one or more programmable processors. The processor 610 may comprise programmable hardware with embedded firmware and may, alternatively or additionally, comprise one or more application specific integrated circuits, ASICs.

The processor 610 is coupled to a memory 620. The processor is configured to read and write data to and from the memory 620. The memory 620 may comprise one or more memory units. The memory units may be volatile or non-volatile. It is to be noted that in some example embodiments there may be one or more units of nonvolatile memory and one or more units of volatile memory or, alternatively, one or more units of non-volatile memory, or, alternatively, one or more units of volatile memory. Volatile memory may be for example RAM, DRAM or SDRAM. Non-volatile memory may be for example ROM, PROM, EEPROM, flash memory, optical storage or magnetic storage. In general, memories may be referred to as non-transitory computer readable media. The memory 620 stores computer readable instructions that are execute by the processor 610. For example, non-volatile memory stores the computer readable instructions and the processor 610 executes the instructions using volatile memory for temporary storage of data and/or instructions.

The computer readable instructions may have been pre-stored to the memory 620 or, alternatively or additionally, they may be received, by the apparatus, via electromagnetic carrier signal and/or may be copied from a physical entity such as computer program product. Execution of the computer readable instructions causes the apparatus 600 to perform functionality described above.

In the context of this document, a “memory” or “computer-readable media” may be any non-transitory media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

The apparatus 600 further comprises, or is connected to, an input unit 630. The input unit 630 comprises one or more interfaces for receiving a user input. The one or more interfaces may comprise for example one or more motion and/or orientation sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons and one or more touch detection units. Further, the input unit 630 may comprise an interface to which external devices may connect to.

The apparatus 600 also comprises an output unit 640. The output unit comprises or is connected to one or more displays capable of rendering visual content such as a light emitting diode, LED, display, a liquid crystal display, LCD and a liquid crystal on silicon, LCoS, display. The output unit 640 further comprises one or more audio outputs. The one or more audio outputs may be for example loudspeakers or a set of headphones.

The apparatus 600 may further comprise a connectivity unit 650. The connectivity unit 650 enables wired and/or wireless connectivity to external networks. The connectivity unit 650 may comprise one or more antennas and one or more receivers that may be integrated to the apparatus 600 or the apparatus 600 may be connected to. The connectivity unit 650 may comprise an integrated circuit or a set of integrated circuits that provide the wireless communication capability for the apparatus 600. Alternatively, the wireless connectivity may be a hardwired application specific integrated circuit, ASIC.

It is to be noted that the apparatus 600 may further comprise various component not illustrated in the FIG. 6. The various components may be hardware component and/or software components.

The apparatus 700 of FIG. 7 illustrates an example embodiment of an apparatus that may be an access node or be comprised in an access node, and that may embody the activator or the reader as described above. The apparatus may be, for example, a circuitry or a chipset applicable to an access node to realize the described embodiments. The apparatus 700 may be an electronic device comprising one or more electronic circuitries. The apparatus 700 may comprise a communication control circuitry 710 such as at least one processor, and at least one memory 720 including a computer program code (software) 722 wherein the at least one memory and the computer program code (software) 722 are configured, with the at least one processor, to cause the apparatus 700 to carry out any one of the example embodiments of the access node described above.

The memory 720 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory may comprise a configuration database for storing configuration data. For example, the configuration database may store current neighbour cell list, and, in some example embodiments, structures of the frames used in the detected neighbour cells. The apparatus 700 may further comprise a communication interface 730 comprising hardware and/or software for realizing communication connectivity according to one or more communication protocols. The communication interface 730 may provide the apparatus with radio communication capabilities to communicate in the cellular communication system. The communication interface may, for example, provide a radio interface to terminal devices. The apparatus 1700 may further comprise another interface towards a core network such as the network coordinator apparatus and/or to the access nodes of the cellular communication system. The apparatus 700 may further comprise a scheduler 1740 that is configured to allocate resources.

Even though the invention has been described above with reference to example embodiments according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.