TECHNICAL FIELD

The technical field relates to radio communications, and more particularly, to the radio performance of cellular radio access nodes like radio repeaters, relays, and base stations.

BACKGROUND

In a typical cellular radio system, wireless terminals (also known as mobile stations and/or user equipment units (UEs)) communicate via a radio access network (RAN) to one or more core networks. The radio access network (RAN) covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a radio base station (RBS), which in some networks may also be called, for example, a "NodeB" (UMTS) or "eNodeB" (LTE). A cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site. Each ceil is identified by an identity within the local radio area, which is broadcast in the cell. The base stations communicate over the air interface operating on radio frequencies with the user equipment units (HE) within range of the base stations.

In some versions of a radio access network, several base stations are typically connected (e.g., by landlioes or microwave) to a controller node (such as a radio network controller (RNC) or a base station controller (BSC)) which supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks.

The Universal Mobile Telecommunications System (UMTS) is a third generation mobi le communication system, which evolved trora the second generation (2G) Global System for Mobile Communications (GSM). UTRAN is essentially a radio access network using wideband code di vision multiple access for user equipment units (UEs). In a fomm known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for third generation networks and UTRAN specifically; and investigate enhanced data, rate and radio capacity. Specifications for the ^' Evolved Universal Terrestrial Radio Access Network (E-UTRA ^' N) are ongoing within the 3 ^rJ Generation Partnership Project (3GPP). The Evolved Universal Terrestrial Radio Access Network (E-UTRAN) comprises the Long Term Evolution (LTE) and System Architecture Evolution (SAB). Long Term Evolution (LTE) is a variant of a 3GPP radio access technology wherein the radio base station nodes are connected to a core network (via Serving Gateways, or SGWs) rather than to radio network controller (RNC) nodes. In general, in LTE the functions of a radio network controller (RNC) node are distributed between the radio base stations nodes (eNodeB's in LTE) and SGWs. As such, the radio access network (RAM) of an LTE system has an essentially "flat" architecture comprising radio base station nodes without reporting to radio network controller (RNC) nodes.

Changes in a wireless environment affect the quality of signal transmitted and received. Reception power rapidly decreases in proportion to increasing distance between wireless coinmunication entities. As a result, a wireless communication system may employ a relay or repeater station (RS)„ a micro/pico base station, or a fenito or home base station to expand coverage and ^' or improve throughput, quality, etc.

A repeater station is typically less sophisticated, expensive, and intelligent than a regular base station (BS), NodeB, eNodeB, or access point (AP). A relay station may perform the same functions as a base station except that a relay does not connect to the backhaul network with a cable or microwave link and instead uses a nearby maeor base station to connect to the backhaul network. Both a repeater and a relay perform an "amplify and forward" (AF) function where it amplifies a signal received from a BS/AP or a MS/lJE and delivers the amplified signal to the MS/UE or the BS/AP. Some relays may perform a decoding and forward (DF) function as well as a scheduling function where communicated, information is restored by performing demodulation and decoding on a signal received front the BS/AP or the .MS/ UE and generating the restored signal by performing coding and modulation which is then sent to the MS/UB or the BS/AP, Any cellular radio access node that performs this "amplify and forward" (AF) function where it amplifies a signal received .from a cellular radio network or a MS/UE and delivers the amplified signal to the MS/UB or the cellular radio network is encompassed by the term "cellular radio access node." This includes relays, repeaters, traditional base stations and access points along with femto or home base stations that are not directly coupled to the radio access/back!iaul network but instead communicate with the radio access; backhaul network via at least one other base station.

The cellular radio access node transmits or receives data using radio resources including one or more of a time resource, a frequency resource, a spatial resource, etc. The time resource may be expressed by a subframe, a symbol, a slot, etc. The frequency resource may be expressed by a subcarrier, a resource block, a component carrier, etc. The spatial resource may be expressed by spatial, multiplexing, an antenna, etc. Such radio resources may be used b a dedicated or shared manner.

Certain cellular radio access nodes like repeaters and relays are not equipped to communicate directly with a operation and maintenance node for the communications system, and thus, do not send fault/alarm data or performance monitoring data directly to operation and maintenance node. As a result, operation and maintenance of certain cellular radio access nodes like repeaters and relays is typically performed by technicians visiting the node site. This is expensive and time consuming. With increasing use of smaller nodes like relays and repeaters in communications networks deployed on a relatively large scale, the cost and time for such site visits also increases. ^' Even where a malfunction is detected, it is not always apparent which relay or repeater is malfunctioning if there are multiple relays or repeaters operating in the same area. Another problem is that between site visits, which may well be infrequent or in the case of relay, repeater, and small base station nodes rarely or non-existent, the network operator may not be made aware either in a timely fashion or ever of that such a node has maifunctioned or is operating below a certain performance level. As a result, it can take a long time before the operator discovers that the reason for a poor "dropped call rate" in m area is due to high noise level in a relay, repeater, or small base station.

SUMMARY

The technology in this application reduces the maintenance effort and expense to monitor the performance of a cellular radio access node (e.g., a relay, repeater, or base station) by having the cellular radio access node automatically conduct radio performance monitoring on itself and pro vide some kind of indication of its status to an operations and maintenance node. A main function of the cellular radio access node is to provide and/or facilitate communications between a communications network and mobile radio terminals. But, in addition, the cellular radio access node monitors performance of a set of one or more radio characteristics associated with die cellular radio access node and determines whether the performance exceeds an associated predetermined threshold. For example, the performance of a received radio signal received by the cellular radio access node or a transmitted radio signal transmitted by the cellular radio access node may be monitored. The cellular radio access node indicates a condition of the cellular radio access node for the operations and maintenance node based on the monitored performance. In addition, the cellular radio access node may take independent action, e.g., shutdown, restart, reduce transmit power, etc., if a monitored condition is exceeded, e.g., transmitted noise exceeds a threshold.

hi one non-limiting application, the cellular radio access node is a relay node or repeater node. The iacilstatrag communications in this application includes receiving a downlink radio signal from a base station intended for a mobile terminal, amplifying the downlink radio signal, and transmitting the amplified downlink radio signal to the mobile terminal, and receiving an uplink radio signal from the mobile terminal, amplifying the uplink radio signal, and transmitting the amplified uplink radio signal to the base station. In another non- limiting application, the cellular radio access node is a macro, micro, pico, or fern to base station.

The indication may include sending a signal to an operations and maintenance node if the monitored performance is satisfactory, e.g., according to some predetermined protocol. The cellular communications node may send the indication to the operations and maintenance node over a radio or a wire connection.

One -non-limiting example way for the cellular radio access node to send the signal is use a communications module used in a mobile terminal. Specifically, the communications module is used to establish a radio connection with the operations and maintenance node and to send the signal to the operations and maintenance node via the radio connection. Although any format may be used, the signal may be sent for example using the internet protocol. (IP) or as a short message service (SMS) message. The communications module, hi one example implementation, may share radio resources allocated to the cellular radio access node, and a controller in the node may control access by the communications module to those shared radio resources.

The monitored performance is, for example, of a set of one or more radio characteristics of a received radio signal or a transmitted signal at the cellular radio access node. If the monitored performance is not satisfactory, then the indicating includes, in one non-limiting example embodiment, not sending the signal to the operations and maintenance node. The absence of the expected signal is detected by the operations and maintenance node. One example way to monitor performance is for the cellular radio access node to compare the set of one or more radio characteristics to a set of one or more corresponding thresholds. If the threshold is not exceeded, then a feedback signal is transmitted to the operations and maintenance node signifying satisfactory node performance. If the threshold is exceeded, then the feedback signal is not transmitted to the operations and maintenance node or a non-satisfactory node performance signal may be sent to the operations and maintenance node. Alternatively., if the threshold is exceeded, then an action may be initiated to improve the performance or otherwise change the operation of the cellular radio access node. In one example variation, the indicating includes sending a message to the operations and maintenance node including monitored perfonnance data regarding the cellular radio access node. Further, an instruction from the operations and maintenance node may be received, and a task performed by the celluiar radio access node based on the received instruction. The task can relate for example to any of the following: reducing transmit power for a signal transmitted by the cellular radio access node, resetting the cellular radio access node, shutting down operation of some part or all of the cellular radio access node.

The set of one or more radio characteristics associated with the cellular radio access node may include one or more of the following: ontband interference caused by a transmission of the received downlink or uplink radio signal or the transmitted downlink or uplink signal node, received interference at the cellular radio access node, poor receiver perfonnance at the cellular radio access node, output power associated with a transmission of the relay node, signal distortion caused by the relay node, or a signal to noise ratio associated with a transmission of the cellular radio access node. If desired, the first, set of one or more radio characteristics associated with the cellular radio access node may be modified.

It is also possible to monitor performance of a second set of one or more conditions associated with hardware components of the cellular radio access node. When the performance of one or more conditions associated with hardware components of the cellular radio access node exceeds an associated predetermined threshold, then a message is sent to an operations and maintenance node based on the monitored performance.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a non-limiting example wireless commttni cati ons system; Figure 2 illustrates communication paths or links between base station, mobile terminal, and relay/repeater node;

Figure 3 is a non-limiting example function block diagram illustrating a relay/repeater node with performance monitoring and reporting;

Figure 4 illustrates an example flowchart entitled O&M relay monitor in accordance with a first non-limiting example embodiment;

Figure 5 illustrates a non-limiting example flowchart entitled O&M relay monitor in accordance with a second non-limiting example embodiment;

Figure 6 a non-limiting example function block diagram illustrating a relay/repeater node with performance monitoring and reporting; and

Figure 7 is a non-limiting signaling diagram showing one example of signaling between the cellular radio access node to the operations and maintenance node.

DETAILED DESCRIPTION

In the following description, for purposes of explanation and non- limitation, specific details are set forth, such as particular nodes, functional entities, techniques, protocols, standards, etc. in order to provide an understanding of the described technology. It will be apparent to one skilled in the art that other embodiments may be practiced apart from the specific details disclosed below. In other instances, detailed descriptions of well-known methods, devices, techniques, etc. are omitted so as not to obscure the description with unnecessary detail Individual function blocks are shown in the figures. Those skilled in the art will appreciate that the functions of those blocks may he implemented using individual hardware circuits, using software programs and data in conjunction with a suitably programmed microprocessor or general purpose computer, using applications specific integrated circuitry (ASIC), and/or using one or more digital signal processors (DSPs), The software program instructions and data may be stored on computer-readable storage medium and when the instructions are executed by a computer or other suitable processor control, the computer or processor performs the functions.

Thus, for example, it will be appreciated by those skilled in the art that block diagrams herein can represent conceptual views of illustrative circuitry or other functional units embodying the principles of the technology. Similarly, it will be appreciated that any flow charts, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable medium, and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

The functions of the various elements including functional blocks, including but. not limited to those labeled or described as "computer", "processor" or "controller", may be provided through the use of hardware such as circuit hardware and/or hardware capable of executing software m the form of coded instructions stored on computer readable medium. Thus, such functions and illustrated functional blocks are to be understood as being either hardware- implemented and/or computer-implemented, and thus machine-implemented.

In terms of hardware implementation, the functional blocks may include or encompass, without limitation, digital signal processor (DSP) hardware, reduced instruction set processor, hardware (e.g., digital or analog) circuitry including but not limited to application specific integrated circuits) (ASIC), and (where appropriate) state machines capable of performing such functions.

in terms of computer implementation, a computer is generally understood to comprise one or more processors or one or more controllers, and the terms computer and processor and controller may be employed interchangeably herein. When provided by a computer or processor or controller, the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or coiitroiler, or by a plurality of individual computers or processors or controllers, some of which may be shared or distributed. Moreover, use of the term "processor" or "controller" shall also be construed to refer to other hardware capable of performing such functions and/or executing software, such as the example hardware recited above.

The technology may be used in any type of cellular radio communications. For ease of description, the term "radio terminal" encompasses any kind of radio communications temiinal/device like user equipment (UE), mobile station (MS), PDAs, cell phones, laptops, etc. The technology described in this application may be used in any cellular radio communications system. One non-limiting example is a WCDMA network which communicates with one or more user equipments (UEs) over a Uu air interface. Typically, one or more core networks communicate with radio network controllers (RNCs) in the WCDMA network over an lu interface. A WCDMA radio access network (RAN) may also be called Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN). The WCDMA RAN handles all tasks that relate to radio access control such as radio resource management and handover control The core network connects the access network to one or more external networks (PSTN, Internet, etc.). The user equipment is connected to one or more radio base stations (Node Bs) over the WCDMA air interface. One or more base stations are coupled to an RNC over an lub interface, and RNCs communicate over an lur interface. The term "base station" is used to encompass any radio node that directly communicates with a radio access or backhaul network, e.g, a NodeB, eNodeB, an access point, a femto base station, or a home base station, etc.

Figure 1 illustrates a non-limiting example cellular communications system that uses relay, repeater, access point, and base station nodes. One or more base stations 10 including access points (APs), base stations (BSs) like NodeBs and eNBs, and home base stations 10 are connected to an access network or backhaul network 16. The access network or backhaul network 16 is coupled to one or more core or backbone network(s) 18. The base stations 10 communicate directly with radio terminals 12 over a radio interface. Some of the base stations 10 a!so communicate directly with relay/repeater nodes 14 over a radio interface and the relay /repeater node .14 relays signals it receives from the base station 10 to one or more radio terminals 12, The inventors conceived of technology that allows a base station 10 and/or a relay/repeater 14 to independently and automatically monitor and communicate radio quali ty performance of that relay/repeater node 14 to an operations and maintenance node (Q&M) 20 and in some example embodiments to receive instructions from the O&M 20 related to monitoring and performance. As shown in Figure 1 , the O&M 20 may be located in the core or backbone network (20a), in the backhaul or radio access network (20b), as a stand-alone node (20c), or in some other suitable location which may include a base station.

Figure 2 illustrates communication paths or links between base station, radio terminal, and relay node. While a base station has a direct connection with an access network or backhaul network, a relay/repeater node must access the access network or backhaul network via a base station. As shown in Figure 2, a relay/repeater node 1.4 receives a backhaul (BH) downlink (PL) radio signal from a base station 10 intended for a mobile terminal, amplifies the downlink radio signal using one or more power amplifiers, and transmits the amplified access downlink radio signal to the radio terminal 12. In the uplink direction, the relay/repeater node 14 receives access uplink radio signal, from the radio terminal 12, amplifies the uplink radio signal using one or more power amplifiers, and. transmits the amplified backhaul uplink radio signal, to the base station 10. Figure 2 also shows that the base station 10 may communicate directly with a radio terminal 12 over an access downlink, and the radio terminal 12 may communicate directly with the base station 10 over an access uplink.

The technology in this application may be used in any "cellular radio access node" that is part of a radio access network including any type of base station, relay, or repeater that performs an amplify and forward function and, as described in the background, does not monitor and report its own radio performance. For purposes of illustration, the following description uses a relay/repeater node as a non-limiting example "cellular radio access node."

Figure 3 is a non-limiting example function block diagram illustrating an example relay /repeater node 14 with performance .monitoring and reporting. The re lay /repeater node 14 includes radio circuitry 22 including one or more radio receivers (Rx), one or more power amplifiers (PA), and one or more radio transmitters (Tx) that perform typical relaying or repeating of radio signals between the network and radio terminals. A relay node, as opposed to a repeater, also contains circuitry (not shown) for decoding a received signal and encoding it before retransmission. The radio circuitry 22 is connected to one or more antennas for communicating radio signals over a radio interface with one or more base stations 10 and one or more radio terminals 12. The relay/repeater node 14 also includes monitoring circuitry 32 for monitoring the radio performance of the relay/repeater node 14. The monitoring circuitry 32 monitors one or more radio performance parameters of the relay/repeater node 14, including one or more radio signal characteristics of a received radio signal received by the cellular radio access node or a transmitted radio signal transmitted by the cellular radio access node, and determines whether the performance exceeds an associated predetermined threshold. The monitoring circuitry 32 indicates a condition of the cellular radio access node for the operations and maintenance node based on the monitored performance. A power supply 33 provides power for operation of the components of the node 14.

In one non-limiting example embodiment, the indication may include sending a signal to an operations and maintenance node if the monitored performance is satisfactory, e.g., a. simple "tick," pulse, message, etc. The cel lular communications node may send the .indication to the operations and maintenance node over a radio or a wire connection. The dotted line is used in Figure 3 to indicate a logical connection with the O&M node 20. The connection is preferably a radio connection, in which case the actual. communications path would be by way of the antenna and radio 22, But the connection may also be a wire connection, if the monitored performance is not satisfactory, no indication is sent. The operations and maintenance node may detect the absence of an expected indication signal, and if desired (though not necessary), take some responsive action, e.g., request specific information from the relay/repeater node.

Figure 4 illustrates a non-limiting example flowchart entitled relay/repeater monitor in accordance with a first non-limiting example embodiment. The monitored performance in step SI is, for example, of one or more radio characteristics of the cellular radio access node. The set of one or more radio characteristics of the node, e.a., related to a received downlink or uplink radio signal or a transmitted downlink or uplink signal. The set of one or more radio characteristics of the node may include one or more of the following examples: ouiband interference caused by a transmission of the relay/repeater node, received interference, poor receiver perfomiance, output power associated with a transmission of the relay/repeater node, signal distortion caused by the relay/repeater node, or a. signal-to-noise ratio associated with a transmission of the relay/repeater node. If desi red, the set of one or more radio characteristics may be modified.

One example way to monitor performance is to compare the set of one or more radio characteristics for the cellular radio access node (e.g., a relay/repeater) to a set of one or more corresponding thresholds (step S2). if the ihreshoJd(s) is(are) not exceeded, then a feedback signal (e.g., a simple tick, pulse, bit, or low bandwidth message, etc.) is transmitted to the operations and maintenance node 20 signifying satisfactory relay/repeater performance (step S3 }. The frequency with which the feedback signal is sent may be configured as desired, but will likeiv mvoive takins into account the bandwidth and processing resources allocated for such feedback from multiple cellular radio access nodes. Bui if a threshold is exceeded., then the feedback signal is not transmitted to the operations and .maintenance node (step S4). Alternatively, a non-satisfactory relay/repeater performance signal may be sent to the operations and maintenance node 20. The O&M node 20 monitors for the feedback signal according to a predetermined protocol, and if the feedback signal is not received in accordance with that protocol then the O&M node 20 may send a command to the node i 4 to reset, shut-down, modify the transmission and/or reception in some way, etc, (step S4). Alternatively, a non-satisfactory relay/repeater performance signal may be sent to the operations and maintenance node 20.

Figure 5 illustrates a non-limiting example flowchart entitled O&M relay/repeater monitor in accordance with a second example embodiment (steps SI and S2 are the same as in Figure 4} in which a more involved monitoring operation may be performed at the relay/repeater node 14. For example, if a threshold is exceeded, the node 14 may initiate some action (step S i 3), e.g., reducing transmit power for a signal transmitted by the relay/repeater node, resetting the relay/repeater node, shutting down operation of some part or all of the relay /repeater node, in one example variation, the feedback signal may include a more detailed message to the operations and maintenance node 20 including monitored performance data regarding the cellular radio access node (step S I 4). Although any signal format may used, the feedback signal and/or optional detailed report may be sent for example using the internet protocol (I P) or as a short message sen-ice (SMS) message. As an example alternative to step SI 3 where the node 14 initiates some sort of responsive action, an instruction from the operations and maintenance node 20 may be received in response to the feedback signal or performance report (step S i 5), and a task is performed by the node 14 based on the received instruction. Again, the task can relate for example to any of the following; reducing transmit power for a signal transmitted by the relay/repeater node, resetting the relay/repeater node, shutting down operation of some part or ail of the relay/repeater node.

It is also possible to monitor performance of a second set of one or more conditions associated with hardware components of the relay node, e.g., temperature, voltage, current, vibration, etc. When the performance of one or more conditions associated with hardware components of the relay/repeater node exceeds an associated predetermined threshold, then the node 14 may take some action {e.g., reducing transmit power for a signal transmitted by the relay/repeater node, resetting the relay/repeater node, shutting down operation of some part or ail of the relay/repeater node), or a message may he sent to an operations and maintenance node based on the exceeded threshold.

Figure 6 a non-limiting example function block diagram illustrating a relay/repeater node 1.4 with performance monitoring and reporting. One non-!imitiiig example way for the relay /repeater radio node 14 to send the signal is use a communications module 34 like that used in a typical mobile terminal 12. Although other communications circuitry may be used, a .mobile terminal communications module is a particularly convenient option since many are already in mass production and configured with software to enable radio communications via radio circuitry in a cellular communications network. The radio terminal communications module 34 is used to establish a radio connection with the operations and maintenance node 20 and to send the signal to the operations and maintenance node via the radio connection. The communications module 34, in one example implementation, shares radio resources allocated to the cellular radio access node with the radio 22, and the controller 30 controls access by the communications module 34 to those shared radio resources, e.g., the communications module 34 transmits (and if desired receives) during time intervals when the relay/repeater node is not transmitting (and receiving).

Fiaiire 7 is a non-limitina sianalint? diagram showing one example of signaling from the cellular radio access node to the operations and maintenance node in a WCMDA type cellular system. This diagram is just for illustration of an example. The signals are radio resource control (RRC) messages. The relay/repeater node 14 {similar to a UE in WCDMA) initiates a connection with the radio access network; using an RRC connection request message. The network responds by sending a connection setup message that is acknowledged when complete by the relay/repeater node 14. The relay /repeater node 14 then sends an uplink direct transfer (udi) short messaging (SM) service request to the network and an uplink direct transfer (udt) short messaging (SM) activate PDP context message to the network. The network responds with a radio bearer setup message acknowledged by the relay/repeater node 14 and follows with a downlink short messaging (SM) activate PDP context accept message. The measurement control signal is sent by the system for configuration of measurements in the IJE. One example includes neighbor cell measurements for handover, in the case of some traffic recording functions, UE- based measurements may also configured using this measurement control signal The O&M node is connected to an IP network as ! 6 shown in Fig. 1 which connects to the svsiern side of the signaling flow. This establishes an IP connection between the relay/repeater node 1.4 and the O&M node over which performance monitoring indication signals, messages, instructions, etc, may be sent. The I P connection may be taken down using the signaling commands shown in the remainder of the figure.

The technology permits cellular radio access nodes like relays, repeaters, and base stations that are not equipped to communicate directly with an operation and maintenance node for the communications system to do just that as well as to monitor their own performance and automatically communicate that performance to operation and maintenance node. As a result, operation and maintenance of such cellular radio access nodes need not be performed by technicians visiting the node site eliminating significant expense and time. Another benefit is that malfunctions are detected, in a particular cellular radio access node and communicated in some fashion in a timely way to an operation and maintenance node rather than having to wait for a technician visit. Indeed, a technician visit may not even be scheduled because there may be not any indication to the network operator that a particular cellular radio access node is not functioning in a satisfactory manner.

Although various embodiments have been shown and described in detail, the claims are not limited to any particular embodiment or example. None of the above description should be read as implying that any particular element, step, range, or function is essential such that it must be included in the claims scope. The scope of patented subject matter is defined only by the claims. The extent of legal protection is defined by the words recited in the allowed claims and their equivalents. All structural and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill so the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the technology described, for it to be encompassed by the present claims. No claim is intended to invoke paragraph 6 of 35 USC § 1 12 unless the words "means for" or "step for' ^" are used. Furthermore, no embodiment, feature, component, or step in this specification is intended to be dedicated to the public regardless of whether the embodiment; feature, component, or step is recited in the claims.