Lateral link communication

Abstract

In accordance with an example aspect of the present disclosure, there is provided a user equipment comprising at least one processing core and at least one memory storing instructions that, when executed by the at least one processing core, cause the user equipment to at least: measure a received signal strength of a unicast transmission, the unicast transmission is received in the user equipment from another user equipment (UE) over a direct UE-to-UE radio link, obtaining at least one power adjustment parameter with respect to the other UE, and including, in a report to a base station node or a further user equipment (UE), either the measured received signal strength modified with the at least one power adjustment parameter, or both the measured received signal strength and the at least one power adjustment parameter.

Description

Technical Field

[0001] The present disclosure relates to wireless communication in the context of a cellular communication system. Background Art

[0002] In the context of a cellular communication system including a plurality of base stations, a user equipment UE of the cellular communication system may be configured to communicate not only using a radio link with a base station, but also by utilizing a direct UE-to-UE radio link. Such a direct UE-to-UE radio link involves a first UE transmitting energy in the form of electromagnetic waves, which are received by a receiver of a second UE, i.e., the direct UE-to-UE radio link does not pass through a base station.

[0003] Without departing from the above basic premise, different terms may be applied to direct UE-to-UE communication. For example, such a communication mode is referred to as sidelink device-to-device D2D, and proximity-based service ProSe. Direct UE-to-UE radio link communication enables useful use cases, such as a UE using another UE as a relay to access the cellular communication system from a location outside the coverage area of the cellular communication system. Summary of the Invention

[0004] According to some aspects, the subject matter of the independent claims is provided. Some embodiments are defined in the dependent claims. The independent claims specify the scope of protection sought by the various embodiments of the present invention. Embodiments, examples, and features (if any) described in this specification that do not fall within the scope of the independent claims will be construed as examples to facilitate understanding of the various embodiments of the present invention.

[0005] According to a first aspect of the present disclosure, there is provided a user equipment, the user equipment including at least one processing core and at least one memory storing instructions, the instructions when executed by the at least one processing core causing the user equipment to at least: measure a received signal strength of a unicast transmission, the unicast transmission being received in the user equipment from another user equipment UE via a direct UE-to-UE radio link, obtain at least one power adjustment parameter regarding the other UE, and include in a report to a base station node or another user equipment UE: the measured received signal strength modified by using the at least one power adjustment parameter, or both the measured received signal strength and the at least one power adjustment parameter.

[0006] According to a second aspect of the present disclosure, there is provided a method, the method comprising: measuring, in a user equipment, a received signal strength of a unicast transmission that is received in the user equipment from another user equipment (UE) via a direct UE-to-UE radio link, obtaining at least one power adjustment parameter regarding the other UE, and including, in a report to a base station node or another UE: the measured received signal strength modified by the at least one power adjustment parameter, or the at least one measured received signal strength and the power adjustment parameter.

[0007] According to a third aspect of the present disclosure, there is provided a user equipment, the user equipment comprising: means for measuring, in the user equipment, a received signal strength of a unicast transmission that is received in the user equipment from another user equipment (UE) via a direct UE-to-UE radio link, means for obtaining at least one power adjustment parameter regarding the other UE, and means for including, in a report to a base station node or another UE, the following items: the measured received signal strength modified by the at least one power adjustment parameter, or both the measured received signal strength and the at least one power adjustment parameter.

[0008] According to a fourth aspect of the present disclosure, there is provided a non-transitory computer-readable medium having a set of computer-readable instructions stored thereon, the set of computer-readable instructions, when executed by at least one processor, causing the user equipment to at least: measure a received signal strength of a unicast transmission that is received in the user equipment from another user equipment (UE) via a direct UE-to-UE radio link, obtain at least one power adjustment parameter regarding the other UE, and include, in a report to a base station node or another UE: the measured received signal strength modified by the at least one power adjustment parameter, or both the measured received signal strength and the at least one power adjustment parameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Illustrates an example system according to at least some embodiments;

[0010] Figure 2 Illustrates an example system according to at least some embodiments;

[0011] Figure 3 Illustrates an example apparatus capable of supporting at least some embodiments;

[0012] Figure 4 Illustrates signaling according to at least some embodiments, and

[0013] Figure 5 is a flowchart of a method according to at least some embodiments. DETAILED DESCRIPTION

[0014] Processes for facilitating direct UE-to-UE communication procedures are described herein. Specifically, the ability to report candidate relay UEs to the network is enhanced by adjusting the measured received signal strength power of signals unicast from candidate relay UEs to account for power control in the direct UE-to-UE link. The network can then make a more informed decision on which candidate relay UE to select as a relay UE, or as a new relay UE in the case where a relay is already in use. An example of how to adjust the measured received signal power is described below.

[0015] Figure 1 An example system in accordance with at least some embodiments is illustrated. Figure 1 The example is a cellular system, but the methods disclosed herein are not limited to being applied in a cellular context. Figure 1 A base station 140 is illustrated, which is configured to operate according to a cellular communication standard (such as Long Term Evolution LTE or Fifth Generation 5G (also known as New Radio NR), both of which are specified by the Third Generation Partnership Project 3GPP). In the case of using a non-cellular system, an access node corresponding to the base station 140 (such as an access point) can be configured according to a non-cellular communication standard (such as Wireless Local Area Network WLAN or Worldwide Interoperability for Microwave Access WiMAX), for example.

[0016] For example, the base station 140 is coupled to a core network node 150 via a link 124, which can include a wired connection. For example, the core network node 150 can include a Mobility Management Entity MME, a Serving Gateway S-GW, or an Access and Mobility Management Function AMF. The core network can include a gateway 160 that is connected to the core network node 150 via a link 145. The gateway 160 is capable of communicating with another network 170 via an inter-network link 156. In a non-cellular system, the core network node 150 and the gateway 160 may not exist. For example, an access node corresponding to the base station 140 is directly connected to another network. For example, the link 145 and the inter-network link 156 can be wired links.

[0017] In addition, in the example case shown, the base station 130 communicates wirelessly with user equipment UEs 120 and 130. For example, each UE can include a smart phone, a feature phone, a tablet or a laptop computer, an Internet of Things IoT node, a smart wearable device, or a connected vehicle connectivity module. Of course, the individual UEs do not need to be of the same type of UE. The wireless communication link 142 connects the base station 140 to the UE 120, and the wireless communication link 143 connects the base station 140 to the UE 130. Each of the wireless communication links 142, 143 can have an uplink for transmitting information from the respective UE to the base station 140, and a downlink for transmitting information from the base station 140 to the respective UE.

[0018] Additionally, Figure 1 the system has direct UE-to-UE links 112 and 113, enabling UE 110 to communicate directly with UEs 120 and 130 respectively. For example, UE 120 can act as a relay for UE 110, allowing UE 110 to access information from another network 170, such as by browsing a website. UE 110 needs to be within the range of direct UE-to-UE communication for the direct UE-to-UE link 112 to function. The communication range of direct UE-to-UE links (such as links 112 and 113) can be shorter than the range of the wireless communication link that the UE has with the base station. The longer the distance between UE 110 and relay UE 120, the higher the power consumption in UE 120. Since UEs are typically battery-powered, their power resources are quite limited.

[0019] When initiating a relay session to the network or in the case where the relay UE needs to be changed, a UE needs to be selected as the relay. For example, an existing relay may be moving out of the range of the direct UE-to-UE link, so the direct UE-to-UE communication session will be interrupted unless the relay is changed. Alternatively, the battery power in the relay UE may drop to such an extent that the relay UE notifies the network and / or UEs it serves that it is unwilling to continue serving as the relay.

[0020] To enable the network to select a new relay UE from the set of possible UEs, in Figure 1 the example, the UE that wants to use the relay (i.e., UE 110) can measure the signal strength of the direct UE-to-UE signals sent by the UEs in the set in its receiver and report the identities of the UEs in the set and the received signal strengths from the corresponding UEs in the set to the network. A UE that uses a relay to access the network can be referred to as a remote UE.

[0021] The direct UE-to-UE signal can be sent as a broadcast discovery message, or the direct UE-to-UE signal can be unicast to a specific UE as part of an ongoing direct UE-to-UE connection between these UEs or as a unicast discovery message in response to a discovery request from a specific UE. Received signal strength measurements can be made for both types of signals. In a 3GPP network, these are referred to as sidelink discovery reference signal received power SD-RSRP and sidelink reference signal received power SL-RSRP respectively.

[0022] Since broadcast signals are not sent to a specific receiver, broadcast signals can be transmitted at a constant power each time. In particular, the constant power used can be the maximum direct UE-to-UE power that the transmitting UE is capable of or permitted to use. It should be noted that there can be different power levels for transmitting UEs with different maximum allowed direct UE-to-UE transmission powers. Since broadcast messages can be used for discovery, it makes sense to use the maximum power because a strong transmission power is most beneficial for the reception of broadcast messages by UEs at a greater distance.

[0023] On the other hand, unicast signals can be part of an ongoing connection between two UEs, so these signals are only directed to one intended receiver. Using the maximum power for these connections would be inefficient because too much power is used, and instead a power control mechanism can be employed to achieve the required quality of service on the direct UE-to-UE link and not use more power than is required for it. A slightly more power can be allowed to obtain reliability against fading.

[0024] For the above reasons, it is difficult to compare the reference signal received power (RSRP) measurements on direct UE-to-UE transmissions for broadcast and unicast. Assuming that the path losses of two transmitting UEs are the same, where one transmitting UE performs broadcast and the other performs unicast, the RSRP measurements on the signals from these UEs may result in very different outcomes. For example, the RSRP measurement result for the signal from the broadcast UE can be the maximum transmission power attenuated by the path loss. At the same time, due to the function of power control, the RSRP measurement result for the signal from the unicast UE can be only the target received power of the power control mechanism, which can depend on the type of service being run. In other words, the RSRP value of the signal from the unicast UE itself does not necessarily disclose any path loss between UEs. Therefore, measuring the RSRP of such a UE does not yield much useful information for, e.g., relay UE selection.

[0025] Figure 2 Illustrates an example system according to at least some embodiments. The same numbers as in Figure 1 represent the same structures. In Figure 2 's case, UE 110 has a relay session with the network via UE 120 acting as a relay. UE 110 and 120 are connected by a direct UE-to-UE link.

[0026] For one reason or another, a new relay needs to be selected to replace UE 120. For example, UE 120 may be moving away from UE 110, making it more difficult and energy-consuming to maintain the direct UE-to-UE link between these devices. The set 201 of candidate UEs includes UE 130, 210, and 220. Generally, candidate UEs are other UEs besides UE 110. UE 110 measures the RSRP values of the signals from each of these UEs. Among these UEs, UE 130 broadcasts its signal to UE 110 via a direct UE-to-UE link, and UE 210 and 220 unicast their signals to UE 110 via the respective direct UE-to-UE links.

[0027] Since the unicast signals from UE 210 and 220 are power-controlled, they are likely to be received at a lower power level in UE 110 than the broadcast signal from UE 130 (which is transmitted from UE 130 at the maximum allowed direct UE-to-UE power). Before providing the set and the measured RSRP values from the corresponding UEs in the set to the base station 140 for the selection of a new relay UE, UE 110 is configured to adjust the measured RSRP values of the unicast signals so that they are more comparable to the RSRP values of the broadcast signals. This provides the technical advantage that a better selection of the relay UE can be made, thus enabling a more reliable direct UE-to-UE link.

[0028] The adjusted RSRP values of the unicast signals can be provided to the network, together with the measured RSRP values of the broadcast signals, in the report of candidate relay UEs (i.e., the set of possible relay UEs), so that the network can meaningfully use the signal strength values when selecting a relay UE from the candidate relay UEs (i.e., from the set). The report is provided from the remote UE to the network. The selection of the relay UE can also depend on factors other than the signal strength values, such as RSRP and the adjusted RSRP. In the case of an indirect-to-indirect path switch with a layer 2 UE-to-network relay, this report can be used for relay reselection, and in the case of a direct-to-indirect and indirect-to-indirect path switch with a UE-to-UE relay, this report can be used for relay selection and reselection. UE-to-UE relay can include the remote UE using the relay UE to communicate with another UE instead of the network. In this case, the report is from the remote UE to the other UE to trigger the other UE to perform relay selection or reselection.

[0029] A first example of the adjustment of the unicast signal RSRP is based on the transmit power headroom of the remote UE. Specifically, the measured RSRP value from the unicast candidate relay UE is compensated using the transmit power headroom of the remote UE itself towards the candidate relay UE. For example, the transmit power headroom can be the difference between the maximum allowed UE-to-UE link transmission power and the UE-to-UE link transmission power currently used by the remote UE (such as UE 110) on the direct UE-to-UE link towards the candidate relay UE:

[0030] Reported RSRP = Measured RSRP + (Maximum TX power - Actual TX power).

[0031] This adjustment relies on the fact that the power control mechanism on the unicast link works in both directions, so the transmit power headroom available in the remote UE (such as Figure 2 UE 110 in ) contains information about the path loss on the direct UE-to-UE link.

[0032] If the maximum transmission power of the direct UE-to-UE link for the candidate relay UE is similar to the maximum transmission power of the remote UE, the value produced by this adjustment will be similar to when the candidate relay UE transmits at maximum power. This will make the RSRP directly comparable to the RSRP of the broadcast signal.

[0033] In addition, the base station 140 can know the maximum transmission power of the candidate relay UE in the set 201, which enables the base station to further adjust the reported RSRP value to account for, for example, the different maximum direct UE-to-UE transmit powers in UEs 210 and 110. For example, if the maximum transmit power of the candidate UE is higher than the maximum transmit power of the remote UE, the base station can increment the reported RSRP value by the difference in the maximum transmit powers between the UEs, and vice versa.

[0034] A second example of the adjustment of the unicast signal RSRP is based on using the measured path loss on the unicast direct UE-to-UE link between the candidate relay UE and the remote UE. In the second example, the measured RSRP value is compensated using the path loss measured at the remote UE (such as Figure 2 UE 110 in ):

[0035] Reported RSRP = Measured RSRP + Path loss.

[0036] Here, the path loss is taken as negative, or alternatively, the path loss can be replaced by the maximum direct UE-to-UE transmit power of the reporting remote UE minus the path loss to obtain a positive value. For example, the path loss parameter can be obtained from the power control mechanism used on the unicast direct UE-to-UE link. For example, these alternatives of the second example can be applied when all candidate relay UEs in the set transmit to the remote UE using unicast. In another alternative of the second example, the path loss can be replaced by (maximum path loss - measured path loss), where the maximum path loss corresponds to the use of the maximum transmit power from the remote UE to the corresponding candidate relay UE. This additional alternative can be applied when the candidate relay UEs in the set can transmit to the remote UE using unicast or broadcast.

[0037] As in the case of the first example, the base station can adjust for different maximum transmit powers between the (multiple) candidate relay UEs and the remote UE that sends the report.

[0038] A third example of the adjustment of the unicast signal RSRP is based on using a hysteresis parameter that is used to evaluate the radio quality on the direct UE-to-UE radio link between the reporting remote UE and the candidate relay UE. In the context of a 3GPP network, this parameter can be referred to as the sl-HystMin parameter. This option makes the unicast RSRP from different relay UE candidates and the broadcast RSRP from other relay UE candidates more comparable.

[0039] In practice, the measured unicast RSRP value is compensated using the hysteresis used to evaluate the radio quality

[0040] Reported RSRP = Measured SL-RSRP + hysteresis_parameter.

[0041] For example, the hysteresis parameter (such as sl-HystMin) can be advertised in the serving cell of the remote UE. When deciding whether to camp on a cell or initiate a direct UE-to-UE connection, the hysteresis parameter defines the margin to be applied to the minimum signal level limit. The hysteresis parameter avoids the situation where a newly initiated connection will need to be reconfigured soon after initiation.

[0042] The advantage of each of the three examples presented above is that they do not require input from the transmitting candidate relay UE. In some embodiments, the candidate relay UE may be configured to indicate to the remote UE at least one power control related parameter, such as the transmit power used by the candidate relay UE to transmit a signal to the remote UE, its maximum transmit power, and / or the path loss to the remote UE when broadcasting or unicasting a signal to the (multiple) remote UEs and signal strength measurements of the signal are expected. This allows the remote UE to more accurately compensate for at least the unicast signal from the (multiple) candidate relay UEs.

[0043] Figure 3 illustrates an example apparatus capable of supporting at least some embodiments. Illustrated is device 300, which may include, for example, a UE such as Figure 1 or Figure 2 UE 110, or include a base station in an applicable portion. Device 300 includes a processor 310, which may include, for example, a single-core or multi-core processor, where a single-core processor includes one processing core and a multi-core processor includes more than one processing core. Processor 310 may generally include a control device. Processor 310 may include more than one processor. When processor 310 includes more than one processor, device 300 may be a distributed device, where the processing of tasks occurs in more than one physical unit. Processor 310 may be a control device. For example, the processing core may include, for example, a Cortex-A8 processing core manufactured by ARM Holdings or a Zen processing core designed by Advanced MicroDevices Corporation. Processor 310 may include at least one Qualcomm Snapdragon and / or Intel Atom processor. Processor 310 may include at least one application specific integrated circuit ASIC. Processor 310 may include at least one field programmable gate array FPGA. Processor 310 may be a component for performing method steps in device 300, such as measuring, obtaining, including, adjusting, and transmitting. Processor 310 may be at least partially configured by computer instructions to perform actions.

[0044] The processor may include circuitry or may be configured as one or more circuitry configured to perform stages of a method according to embodiments described herein. As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) an implementation with only hardware circuitry, such as an implementation with only analog and / or digital circuitry, and (b) a combination of hardware circuitry and software, such as, as applicable: (i) a combination of (one or more) analog and / or digital hardware circuitry and software / firmware, and (ii) any portion of (one or more) hardware processors with software (including (one or more) digital signal processors, software, and (one or more) memories that work together to cause a device such as a user equipment or a base station to perform various functions), and (c) (one or more) hardware circuitry and / or (one or more) processors, such as (one or more) microprocessors or a portion of (one or more) microprocessors, that require software (e.g., firmware) to operate, but where the software may be absent when it is not needed for operation.

[0045] This definition of circuitry applies to all uses of the term in this application (including in any claims). As a further example, as used in this application, the term circuitry also encompasses an implementation with only hardware circuitry or a processor (or processors) or a portion of a hardware circuitry or processor and its accompanying software and / or firmware. For example, if applicable to a particular claim element, the term circuitry also encompasses a baseband integrated circuit or a processor integrated circuit for a mobile device, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

[0046] Device 300 may include a memory 320. The memory 320 may include a random access memory and / or a permanent memory. The memory 320 may include at least one RAM chip. For example, the memory 320 may include, for example, solid state, magnetic, optical, and / or holographic memories. The memory 320 may be at least partially accessible by a processor 310. The memory 320 may be at least partially included in the processor 310. The memory 320 may be a component for storing information. The memory 320 may include computer instructions that the processor 310 is configured to execute. When computer instructions configured to cause the processor 310 to perform certain actions are stored in the memory 320 and the device 300 as a whole is configured to operate using the computer instructions from the memory 320 under the guidance of the processor 310, the processor 310 and / or at least one of its processing cores may be regarded as being configured to perform the above certain actions. The memory 320 may be at least partially included in the processor 310. The memory 320 may be at least partially located outside the device 300 but accessible by the device 300. The memory 320 may be non-transitory. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, rather than a signal), rather than a limitation on the persistence of data storage (e.g., RAM vs. ROM).

[0047] Device 300 may include a transmitter 330. Device 300 may include a receiver 340. The transmitter 330 and the receiver 340 may be configured to transmit and receive information respectively according to at least one cellular or non-cellular standard. The transmitter 330 may include more than one transmitter. The receiver 340 may include more than one receiver. The transmitter 330 and / or the receiver 340 may be configured to operate according to standards such as Global System for Mobile Communications (GSM), Wideband Code Division Multiple Access (WCDMA), 5G, Long Term Evolution (LTE), IS-95, Wireless Local Area Network (WLAN), Ethernet, and / or Worldwide Interoperability for Microwave Access (WiMAX).

[0048] Device 300 may include a Near Field Communication (NFC) transceiver 350. The NFC transceiver 350 may support at least one NFC technology, such as NFC, Bluetooth, Wibree, or similar technologies.

[0049] Device 300 may include a user interface UI 360. UI 360 may include at least one of the following: a display, a keyboard, a touch screen, a vibrator arranged to signal the user by causing device 300 to vibrate, a speaker, and a microphone. A user may be able to operate device 300 via UI 360, such as to receive an incoming call, initiate a phone call or a video call, browse the Internet, manage digital files stored in memory 320 or on a cloud accessible via transmitter 330 and receiver 340 or via NFC transceiver 350, and / or play games.

[0050] Device 300 may include or be arranged to receive a user identification module 370. User identification module 370 may include, for example, a subscriber identification module SIM card installable in device 300. User identification module 370 may include information identifying a subscription of a user of device 300. User identification module 370 may include password information that may be used to authenticate the identity of a user of device 300 and / or facilitate encryption of communication information and billing for communications made by the user of device 300 via device 300.

[0051] Processor 310 may be equipped with a transmitter arranged to output information from processor 310 to other devices included in device 300 via electrical conductors internal to device 300. Such a transmitter may include a serial bus transmitter arranged to output information, for example, to memory 320 via at least one electrical conductor for storage therein. As an alternative to a serial bus, the transmitter may include a parallel bus transmitter. Similarly, processor 310 may include a receiver arranged to receive information in processor 310 from other devices included in device 300 via electrical conductors internal to device 300. Such a receiver may include a serial bus receiver arranged to receive information for processing in processor 310, for example, from receiver 340 via at least one electrical conductor. As an alternative to a serial bus, the receiver may include a parallel bus receiver.

[0052] Device 300 may include Figure 3 additional devices not shown. For example, in the case where device 300 includes a smart phone, it may include at least one digital camera. Some devices 300 may include a rear camera and a front camera, where the rear camera may be used for digital photography while the front camera is used for video calls. Device 300 may include a fingerprint sensor arranged to at least partially authenticate a user of device 300. In some embodiments, device 300 lacks at least one of the above devices. For example, some devices 300 may lack NFC transceiver 350 and / or user identification module 370.

[0053] The processor 310, the memory 320, the transmitter 330, the receiver 340, the NFC transceiver 350, the UI 360, and / or the user identification module 370 may be interconnected in a variety of different ways by electrical conductors inside the device 300. For example, each of the above devices may be individually connected to a main bus inside the device 300 to allow the devices to exchange information. However, those skilled in the art will understand that this is just an example, and according to embodiments, various ways of interconnecting at least two of the above devices may be selected without departing from the scope of the present invention.

[0054] Figure 4 Signaling according to at least some embodiments is illustrated. On the vertical axis, starting from the left, there are Figure 2 base station 140, remote UE 110, and candidate relay UEs 130 and 210. Time progresses from top to bottom.

[0055] In stage 410, the remote UE 110 has a direct UE-to-UE link with the relay UE, which is not illustrated in Figure 4 Via the direct UE-to-UE link to the relay UE, the remote UE 110 can access the Internet, for example, which represents UE-to-network relay, or access information in another UE that also has a direct UE-to-UE link with the relay UE, for example, which represents UE-to-UE relay.

[0056] To facilitate path switching and selection of a new relay UE, the UE 110 measures the RSRP of signals from candidate relay UEs 130, 210 in stages 420 and 430, respectively. The candidate relay UE 130 broadcasts its stage 420 signal with the maximum allowed direct UE-to-UE transmission power, while the candidate relay UE 210 unicasts its stage 430 signal using power control with the remote UE 110.

[0057] In stage 440, the remote UE 110 uses, for example, one of the three methods described above (based on power margin, path loss, or hysteresis parameter) to adjust the reference signal received power measurement of the stage 430 signal to perform this adjustment.

[0058] In stage 450, the remote UE 110 provides a report to the base station 140 or another UE, the report including the UE identifiers of the respective candidate relay UEs 130 and 210 in the set of candidate relay UEs, the broadcast received signal power value, and the adjusted unicast received signal power value. In some embodiments, the remote UE provides the measured unicast received signal power value and at least one adjustment parameter, such as a margin, path loss, or hysteresis parameter, instead of the adjusted unicast received signal power value. Examples of adjustment parameters include power margin values, path loss, hysteresis parameters, and the maximum transmit power provided by the candidate relay UE, and / or the actual transmit power provided by the candidate relay UE (if provided to the remote UE by the candidate relay UE).

[0059] In stage 460, the base station 140 or another UE selects a new relay UE from the set of candidate relay UEs, in this case UE 130 or UE 210. The selection is at least partially based on the received signal power values of the report in stage 450. The selection can also be based on factors other than the reported signal power values. As described above, in some embodiments, the base station is also configured to adjust the adjusted received power value based on the maximum transmit power of the UE known to the base station. In some embodiments, the base station is configured to perform the adjustment of the received power value based on at least one adjustment parameter provided by the remote UE to the base station.

[0060] In stage 470, the base station 140 or another UE notifies the remote UE 110 of the decision as to which UE in the candidate relay UEs has been selected as the new relay UE.

[0061] Figure 5 is a flowchart of a method according to at least some embodiments. For example, the stages of the illustrated method can be performed in the remote UE 110 or in a control device configured to control the functions of the remote UE when installed in the remote UE.

[0062] Stage 510 includes measuring the received signal strength of a unicast transmission in a user equipment, the unicast transmission being received in the user equipment from a candidate user equipment UE via a direct UE-to-UE radio link. Stage 520 includes obtaining at least one power adjustment parameter regarding the candidate UE. Finally, stage 530 includes including in a report to a base station node or another user equipment UE: the measured received signal strength modified with at least one power adjustment parameter, or both the measured received signal strength and at least one power adjustment parameter.

[0063] It should be understood that the embodiments of the present invention disclosed herein are not limited to the specific structures, process steps or materials disclosed herein, but can be extended to equivalents that those skilled in the relevant art will recognize. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and are not intended to be limiting.

[0064] References to one embodiment or embodiments throughout this specification mean that the particular features, structures, or characteristics described in connection with that embodiment are included in at least one embodiment of the present invention. Thus, the phrases "in one embodiment" or "in an embodiment" appearing in various places throughout this specification are not necessarily all referring to the same embodiment. When terms such as about or substantially are used to refer to a numerical value, the exact numerical value is also disclosed.

[0065] As used herein, for convenience, multiple items, structural elements, constituent elements, and / or materials may be presented in a common list. However, such lists should be construed as each member of the list being independently identified as a separate and unique member. Thus, any individual member of such a list should not be construed as a de facto equivalent of any other member of the same list solely based on its presentation in the common group (without contrary indication). In addition, various embodiments and examples of the present invention may be referred to herein, as well as alternatives for its various components. It should be understood that these embodiments, examples, and alternatives should not be construed as de facto equivalents of each other, but rather as separate and autonomous representations of the present invention.

[0066] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the foregoing description, numerous specific details, such as examples of length, width, shape, etc., are provided to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the relevant art will recognize that the present invention may be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the present invention.

[0067] While the above examples illustrate the principles of the present invention in one or more specific applications, those of ordinary skill in the art will understand that many modifications can be made to the forms of implementation, usage, and details without the exercise of creative faculty and without departing from the principles and concepts of the present invention. Thus, the present invention is not limited except as defined by the claims presented herein.

[0068] In this specification, the verbs "comprise" and "include" are used as open limitations, neither excluding nor requiring the presence of features not recited. Features recited in dependent claims may be combined freely with each other unless otherwise explicitly stated. Further, it should be understood that the use of "a" or "an" (i.e., the singular form) in this specification does not exclude a plurality.

[0069] Industrial applicability

[0070] At least some embodiments of the present invention find industrial applications in operating a wireless communication network.

Claims

1. A user equipment, comprising at least one processing core and at least one memory storing instructions which, when executed by the at least one processing core, cause the user equipment to at least: - Measure the received signal strength of a unicast transmission, which is received in the user equipment from another user equipment UE via a direct UE-to-UE radio link; - Obtain at least one power adjustment parameter regarding the other UE, and - In a report to a base station node or another user equipment UE Include: ■ The measured received signal strength modified by using the at least one power adjustment parameter, or ■ Both the measured received signal strength and the at least one power adjustment parameter.

2. The user equipment according to claim 1, wherein the at least one power adjustment parameter regarding the other UE comprises one or more of the following: a power headroom value indicating how much the other UE can increase its transmission power without exceeding the maximum transmission power; a path loss value indicating how much the direct UE-to-UE radio link attenuates them due to signals passing through the direct UE-to-UE radio link; and a hysteresis value used to evaluate the radio link quality of the direct UE-to-UE radio link.

3. The user equipment according to claim 1 or 2, further configured to: include in the report a second measured signal strength of a broadcast transmission, which is received in the device from a second other UE via a second direct UE-to-UE radio link, and the user equipment is not configured to adjust the second measured signal strength to account for power control before including the second measured signal strength in the report.

4. The user equipment according to any one of claims 1 to 3, further configured to: include in the report a third measured signal strength of a unicast transmission, which is received in the device from a third other UE via a third direct UE-to-UE radio link, the third measured signal strength being modified by using at least one power adjustment parameter regarding the third other UE, or include in the report the third measured signal strength and the power adjustment parameter regarding the third other UE.

5. The user equipment according to any one of claims 1 to 4, wherein the report is a sidelink measurement report in a fifth-generation cellular communication system.

6. The user equipment according to any one of claims 1 to 5, wherein the report is a measurement report, and the user equipment is configured to: send the measurement report to the base station node or to the other UE as part of a process of switching an indirect path between the user equipment and the base station node or the other UE, wherein the other UE is a relay candidate in the report.

7. The user equipment according to claim 6, wherein the user equipment is configured to send the report directly to the base station or to send the report to the base station via a current relay UE such that at the moment when the user equipment sends the report, the user equipment does not have a radio connection to the base station.

8. The user equipment according to claim 6, wherein the user equipment is configured to send the report directly to the other UE or to send the report to the other UE via a current relay UE such that at the moment when the device sends the report, the device does not have a radio connection to the other UE.

9. A method comprising: - measuring, in a user equipment, a received signal strength of a unicast transmission that is received in the user equipment from another user equipment UE via a direct UE-to-UE radio link; - obtaining at least one power adjustment parameter regarding the other UE, and - including in a report to a base station node or another UE: ■ the measured received signal strength modified using the at least one power adjustment parameter, or ■ both the at least one measured received signal strength and the power adjustment parameter.

10. The method according to claim 9, wherein the at least one power adjustment parameter regarding the other UE comprises one or more of the following: a power headroom value indicating how much the other UE can increase its transmission power without exceeding a maximum transmission power; a path loss value indicating how much the direct UE-to-UE radio link attenuates due to signals passing through the direct UE-to-UE radio link; and a hysteresis value used to evaluate a radio link quality of the direct UE-to-UE radio link.

11. The method according to claim 9 or 10, further comprising: including in the report a second measured signal strength of a broadcast transmission that is received in the device from a second other UE via a second direct UE-to-UE radio link, the method including adjusting the second measured signal strength to account for power control before including the second measured signal strength in the report.

12. The method according to any one of claims 9 to 11, further comprising: including in the report a third measured signal strength of a unicast transmission that is received in the device from a third other UE via a third direct UE-to-UE radio link, the third measured signal strength being modified using at least one power adjustment parameter regarding the third other UE, or including in the report the third measured signal strength and the power adjustment parameter regarding the third other UE.

13. The method according to any one of claims 9 to 12, wherein the report is a sidelink measurement report in a fifth generation cellular communication system.

14. The method according to any one of claims 9 to 13, wherein the method comprising: As part of the path switching procedure, the report is sent via the current relay UE to the base station node or to the other UE, where the UE is a relay candidate in the report.

15. A user equipment, comprising: - means for measuring, in the user equipment, the received signal strength of a unicast transmission received in the user equipment from another user equipment UE over a direct UE-to-UE radio link; - means for obtaining at least one power adjustment parameter regarding the other UE, and - means for including in a report to a base station node or another UE: ■ the measured received signal strength modified using the at least one power adjustment parameter, or ■ both the measured received signal strength and the at least one power adjustment parameter.

16. A non-transitory computer-readable medium having a set of computer-readable instructions stored thereon, the set of computer-readable instructions, when executed by at least one processor, causing the user equipment to at least: - measure the received signal strength of a unicast transmission received in the user equipment from another user equipment UE over a direct UE-to-UE radio link; - obtain at least one power adjustment parameter regarding the other UE, and - in a report to a base station node or another UE include: ■ the measured received signal strength modified using the at least one power adjustment parameter, or ■ both the measured received signal strength and the at least one power adjustment parameter.

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