Related Applications

[0001] This application claims the benefit of provisional patent application serial number 63/336,662, filed April 29, 2022, the disclosure of which is hereby incorporated herein by reference in its entirety.

Technical Field

[0002] The present disclosure relates to a wireless network such as, e.g., a Radio Access Network (RAN) of a cellular communications system and, more particularly, to relaying in a wireless network.

Background

Sidelink Transmissions in NR

[0003] Sidelink transmissions over Third Generation Partnership Project (3GPP) New Radio (NR) are specified for Release 16. These are enhancements of the ProSe (PROximity-based SErvices) specified for Long Term Evolution (LTE). Four new enhancements are particularly introduced to NR sidelink transmissions as follows:

• Support for unicast and groupcast transmissions are added in NR sidelink. For unicast and groupcast, the Physical Sidelink Feedback Channel (PSFCH) is introduced for a receiver User Equipment (UE) to feed back the decoding status to a transmitter UE.

• Grant-free transmissions, which are adopted in NR uplink transmissions, are also provided in NR sidelink transmissions to improve the latency performance.

• To alleviate resource collisions among different sidelink transmissions launched by different UEs, the channel sensing and resource selection procedures are enhanced, which also leads to a new design of the Physical Sidelink Control Channel (PSCCH).

• To achieve a high connection density, congestion control and thus the Quality of Service (QoS) management is supported in NR sidelink transmissions.

[0004] To enable the above enhancements, new physical channels and reference signals are introduced in NR (available in LTE before.):

• Physical Sidelink Shared Channel (PSSCH) - a sidelink (SL) version of PDSCH: The PSSCH is transmitted by a sidelink transmitter UE, which conveys sidelink transmission data, System Information Blocks (SIBs) for Radio Resource Control (RRC) configuration, and a part of the Sidelink Control Information (SCI). • PSFCH - a SL version of the Physical Uplink Control Channel (PUCCH): The PSFCH is transmitted by a sidelink receiver UE for unicast and groupcast, which conveys 1 bit information over 1 Resource Block (RB) for the Hybrid Automatic Repeat Request (HARQ) acknowledgement (ACK) and the negative ACK (NACK). In addition, Channel State Information (CSI) is carried in the Medium Access Control (MAC) Control Element (CE) over the PSSCH instead of the PSFCH.

• Physical Sidelink Common Control Channel (PSCCH) - a SL version of the Physical Downlink Control Channel (PDCCH): When the traffic to be sent to a receiver UE arrives at a transmitter UE, a transmitter UE should first send the PSCCH, which conveys a part of SCI (SL version of Downlink Control Information (DO)) to be decoded by any UE for the channel sensing purpose, including the reserved time-frequency resources for transmissions, Demodulation Reference Signal (DMRS) pattern and antenna port, etc.

• Sidelink Primary/Secondary Synchronization Signal (S-PSS/S-SSS): Similar to downlink transmissions in NR, in sidelink transmissions, primary and secondary synchronization signals (called S-PSS and S-SSS, respectively) are supported. Through detecting the S- PSS and S-SSS, a UE is able to identify the Sidelink Synchronization Identity (SSID) from the UE sending the S-PSS/S-SSS. Through detecting the S-PSS/S-SSS, a UE is therefore able to know the characteristics of the UE transmitting the S-PSS/S-SSS. A series of processes of acquiring timing and frequency synchronization together with SSIDs of UEs is called initial cell search. Note that the UE sending the S-PSS/S-SSS may not be necessarily involved in sidelink transmissions, and a node (UE/ evolved or enhanced NodeB (eNB) / NR base station (gNB)) sending the S-PSS/S-SSS is called a synchronization source. There are two S-PSS sequences and three hundred and thirty-six (336) S-SSS sequences forming a total of six hundred and seventy-two (672) SSIDs in a cell.

• Physical Sidelink Broadcast Channel (PSBCH): The PSBCH is transmitted along with the S-PSS/S-SSS as a Synchronization Signal/PSBCH block (SSB). The SSB has the same numerology as PSCCH/PSSCH on that carrier, and an SSB should be transmitted within the bandwidth of the configured Bandwidth Part (BWP). The PSBCH conveys information related to synchronization, such as the Direct Frame Number (DFN), indication of the slot and symbol level time resources for sidelink transmissions, incoverage indicator, etc. The SSB is transmitted periodically at every 160 milliseconds (ms). • DMRS, Phase Tracking Reference Signal (PT-RS), Channel State Information Reference Signal (CSI-RS): These physical reference signals supported by NR downlink/uplink transmissions are also adopted by sidelink transmissions. Similarly, the PT-RS is only applicable for Frequency Range 2 (FR2) transmission.

[0005] Another new feature is the two-stage SCI. This a version of the DO for SL. Unlike the DO, only part (first stage) of the SCI is sent on the PSCCH. This part is used for channel sensing purposes (including the reserved time-frequency resources for transmissions, DMRS pattern and antenna port, etc.) and can be read by all UEs while the remaining (second stage) SCI includes scheduling and control information such as a 8-bits source identity (ID) and a 16-bits destination ID, New Data Indicator (NDI), Redundancy Version (RV), and Hybrid Automatic Repeat Request (HARQ) process Identity (ID) and is sent on the PSSCH to be decoded by the receiver UE.

[0006] Similar as for ProSe in LTE, NR sidelink transmissions have the following two modes of resource allocations:

• Mode 1: Sidelink resources are scheduled by a gNB.

• Mode 2: The UE autonomously selects sidelink resources from a (pre-)configured sidelink resource pool(s) based on the channel sensing mechanism.

For the in-coverage UE, a gNB can be configured to adopt Mode 1 or Mode 2. For the out-of- coverage UE, only Mode 2 can be adopted.

[0007] As in LTE, scheduling over the sidelink in NR is done in different ways for Mode 1 and Mode 2. Mode 1 supports the following two kinds of grants:

• Dynamic Grant: When the traffic to be sent over sidelink arrives at a transmitter UE, this UE should launch the four-message exchange procedure to request sidelink resources from a gNB (i.e., Scheduling Request (SR) on the uplink (UL), grant, Buffer Status Report (BSR) on UL, and grant for data on SL sent to UE). During the resource request procedure, a gNB may allocate a Sidelink Radio Network Temporary Identifier (SL- RNTI) to the transmitter UE. If this sidelink resource request is granted by a gNB, then a gNB indicates the resource allocation for the PSCCH and the PSSCH in the DO conveyed by PDCCH with Cyclic Redundancy Check (CRC) scrambled with the Sidelink Radio Network Temporary Identifier (SL-RNTI). When a transmitter UE receives such a DO, a transmitter UE can obtain the grant only if the scrambled CRC of DO can be successfully solved by the assigned SL-RNTI. A transmitter UE then indicates the timefrequency resources and the transmission scheme of the allocated PSSCH in the PSCCH and launches the PSCCH and the PSSCH on the allocated resources for sidelink transmissions. When a grant is obtained from a gNB, a transmitter UE can only transmit a single Transport Block (TB). As a result, this kind of grant is suitable for traffic with a loose latency requirement.

• Configured Grant: For the traffic with a strict latency requirement, performing the four- message exchange procedure to request sidelink resources may induce unacceptable latency. In this case, prior to the traffic arrival, a transmitter UE may perform the four- message exchange procedure and request a set of resources. If a grant can be obtained from a gNB, then the requested resources are reserved in a periodic manner. Upon traffic arriving at a transmitter UE, this UE can launch the PSCCH and the PSSCH on the upcoming resource occasion. In fact, this kind of grant is also known as grant-free transmissions.

In both dynamic grant and configured grant, a sidelink receiver UE cannot receive the DCI (since it is addressed to the transmitter UE), and therefore a receiver UE should perform blind decoding to identify the presence of PSCCH and find the resources for the PSSCH through the SCI.

[0008] When a transmitter UE launches the PSCCH, CRC is also inserted in the SCI without any scrambling.

[0009] In the Mode 2 resource allocation, when traffic arrives at a transmitter UE, this transmitter UE should autonomously select resources for the PSCCH and the PSSCH. To further minimize the latency of the feedback HARQ Acknowledgement (ACK)/Negative Acknowledgement (NACK) transmissions and subsequently retransmissions, a transmitter UE may also reserve resources for PSCCH/PSSCH for retransmissions. To further enhance the probability of successful TB decoding at one shot and thus suppress the probability of performing retransmissions, a transmitter UE may repeat the TB transmission along with the initial TB transmission. This mechanism is also known as blind retransmission. As a result, when traffic arrives at a transmitter UE, then this transmitter UE should select resources for the following transmissions:

1) The PSSCH associated with the PSCCH for initial transmission and blind retransmissions.

2) The PSSCH associated with the PSCCH for retransmissions.

[0010] Since each transmitter UE in sidelink transmissions should autonomously select resources for above transmissions, how to prevent different transmitter UEs from selecting the same resources turns out to be a critical issue in Mode 2. A particular resource selection procedure is therefore imposed to Mode 2 based on channel sensing. The channel sensing procedure involves measuring Reference Signal Received Power (RSRP) on different subchannels and requires knowledge of the different UEs power levels of DMRS on the PSSCH or the DMRS on the PSCCH depending on the configuration. This information is known only after receiver SCI is launched by (all) other UEs. The sensing and selection algorithm is rather complex.

Layer 2 (L2) UE-to-Network Relay

[0011] In 3GPP Technical Report (TR) 23.752 V17.0.0, clause 6.7, layer-2 based UE-to-

Network relay is described as shown in the following excerpt:

***** START EXCERPT FROM 3GPP TR 23.752 V17.0.0 *****

6.7.2.1 General

In this clause, the protocol architecture supporting a L2 UE-to-Network Relay UE is provided.

The L2 UE-to-Network Relay UE provides forwarding functionality that can relay any type of traffic over the PC5 link.

The L2 UE-to-Network Relay UE provides the functionality to support connectivity to the 5GS for Remote UEs. A UE is considered to be a Remote UE if it has successfully established a PC5 link to the L2 UE-to- Network Relay UE. A Remote UE can be located within NG-RAN coverage or outside of NG-RAN coverage.

***** _END EXCERPT FROM 3GPP TR 23.752 V17.0.0 *****

[0012] The user plane protocol stack and the control plane protocol stacks for Layer 2 UE-to-

Network relay are described in 3GPP TR 23.752 V17.0.0 as shown in the following excerpt:

***** START EXCERPT FROM 3GPP TR 23.752 V17.0.0 *****

A.2 Control and User Plane Protocols for Layer 2 UE-to- Network Relay

A.2.1 User Plane Protocol Stack

Figure A.2.1 -1 , illustrates the protocol stack for the user plane transport, related to a PDU Session, including a Layer 2 UE-to-Network Relay UE. The PDU layer corresponds to the PDU carried between the Remote UE and the Data Network (DN) over the PDU session. The PDU layer corresponds to the PDU carried between the Remote UE and the Data Network (DN) over the PDU session. The SDAP and PDCP protocols are as specified in TS 38.300 [11]. It is important to note that the two endpoints of the PDCP link are the Remote UE and the gNB. The relay function is performed below PDCP. This means that data security is ensured between the Remote UE and the gNB without exposing raw data at the UE-to-Network Relay UE.

[REPRODUCED HEREIN AS FIGURE 1] Figure A.2.1-1 : User Plane Stack for L2 UE-to-Network Relay UE

The adaptation layer within the UE-to-Network Relay UE and gNB can differentiate signalling radio bearers (SRBs) and data radio bearers (DRBs) for a particular Remote UE. The adaption layer is also responsible for mapping PC5 traffic to one or more DRBs of the Uu. The definition of the adaptation layer is under the responsibility of RAN WG2.

Editor's note: The details of the services provided by the adaption layer is left to RAN WG2.

A.2.2 Control Plane Protocol Stack

Figure A.2.2-1 , illustrates the protocol stack of the NAS connection for the Remote UE to the NAS-MM and NAS-SM components. The NAS messages are transparently transferred between the Remote UE and gNB over the Layer 2 UE-to-Network Relay UE using:

- PDCP end-to-end connection where the role of the UE-to-Network Relay UE is to relay the PDUs over the signalling radio bear without any modifications.

- N2 connection between the gNB and AMF over N2.

- N11 connection AMF and SMF over N1 1 .

The role of the UE-to-Network Relay UE is to relay the PDUs from the signalling radio bearer without any modifications.

[REPRODUCED HEREIN AS FIGURE 2] Figure A.2.2-1 : Control Plane for L2 UE-to-Network Relay UE

Editor's note: The Remote UE behaviour at the RRC layer is FFS in RAN WG2.

***** _END EXCERPT FROM 3GPP TR 23.752 V17.0.0 *****

Relay Establishment Procedure

[0013] The relay establishment procedure is described in 3GPP TR 38.836 V17.0.0 as shown in the following excerpt:

***** START EXCERPT FROM 3GPP TR 38.836 V17.0.0 *****

4.5.5.1 Connection Management

Remote UE needs to establish its own PDU sessions/DRBs with the network before user plane data transmission.

PC5-RRC aspects of Rel-16 NR V2X PC5 unicast link establishment procedures can be reused to setup a secure unicast link between Remote UE and Relay UE for L2 UE-to-Network relaying before Remote UE establishes a Uu RRC connection with the network via Relay UE.

For both in-coverage and out-of-coverage cases, when the Remote UE initiates the first RRC message for its connection establishment with gNB, the PC5 L2 configuration for the transmission between the Remote UE and the UE-to-Network Relay UE can be based on the RLC/MAC configuration defined in specifications.

The establishment of Uu SRB1/SRB2 and DRB of the Remote UE is subject to legacy Uu configuration procedures for L2 UE-to-Network Relay. The following high level connection establishment procedure applies to L2 UE-to-Network Relay:

[REPRODUCED HEREIN AS FIGURE 3]

Figure 4.5.5.1-1 : Procedure for Remote UE connection establishment

Step 1. The Remote and Relay UE perform discovery procedure, and establish PC5-RRC connection using the legacy Rel-16 procedure as a baseline.

Step 2. The Remote UE sends the first RRC message (i.e., RRCSetupRequest) for its connection establishment with gNB via the Relay UE, using a default L2 configuration on PC5. The gNB responds with an RRCSetup message to Remote UE. The RRCSetup delivery to the Remote UE uses the default configuration on PC5. If the Relay UE had not started in RRC_CONNECTED, it would need to do its own connection establishment upon reception of a message on the default L2 configuration on PC5. The details for Relay UE to forward the RRCSetupRequesf/ RRCSetup message for Remote UE at this step can be discussed in Wl phase.

Step 3. The gNB and Relay UE perform relaying channel setup procedure over Uu. According to the configuration from gNB, the Relay/Remote UE establishes an RLC channel for relaying of SRB1 towards the Remote UE over PC5. This step prepares the relaying channel for SRB1 .

Step 4. Remote UE SRB1 message (e.g. an RRCSetupComplete message) is sent to the gNB via the Relay UE using SRB1 relaying channel over PC5. Then the Remote UE is RRC connected over Uu.

Step 5. The Remote UE and gNB establish security following legacy procedure and the security messages are forwarded through the Relay UE.

Step 6. The gNB sets up additional RLC channels between the gNB and Relay UE for traffic relaying. According to the configuration from gNB, the Relay/Remote UE sets up additional RLC channels between the Remote UE and Relay UE for traffic relaying. The gNB sends an RRCReconfiguration to the Remote UE via the Relay UE, to set up the relaying SRB2/DRBs. The Remote UE sends an RRCReconfigurationComplete to the gNB via the Relay UE as a response.

Besides the connection establishment procedure, for L2 UE-to-Network relay:

- The RRC reconfiguration and RRC connection release procedures can reuse the legacy RRC procedure, with the message content/configuration design left to Wl phase.

- The RRC connection re-establishment and RRC connection resume procedures can reuse the legacy RRC procedure as baseline, by considering the above connection establishment procedure of L2 UE-to-Network Relay to handle the relay specific part, with the message content/configuration design left to Wl phase.

***** _END EXCERPT FROM 3GPP TR 38.836 V17.0.0 *****

Summary

[0014] Systems and methods are disclosed that relate to signaling and mechanisms for relay User Equipment (UE) discovery message transmission for multi-hop scenarios. In one embodiment, a method performed by a controlling entity for multi-hop sidelink communication comprises configuring a plurality of UEs to report information about associated wireless links. The associated wireless links comprise associated sidelinks and, if any, direct wireless links to a network node. The plurality of UEs comprise one or more relay UE and a candidate relay UE for candidate end-to-end link from the controlling entity to a remote UE, the candidate end-to-end link comprising a candidate multi-hop sidelink to a remote UE via the one or more relay UEs and the candidate relay UE. The method further comprises receiving the information about the associated wireless links from the plurality of UEs, determining whether the candidate relay UE should transmit a discovery announcement message based on the information about the associated wireless links of the one or more relay UEs and the candidate relay UE for the candidate end-to-end link to the remote UE, and transmitting, directly or indirectly to the candidate relay UE, an indication of a result of the determining. In this manner, good end-to-end wireless multi-hop sidelink link performance or quality can be ensured before a relay UE makes itself available to remote UEs by transmitting a discovery message.

[0015] In one embodiment, determining whether the candidate relay UE should transmit a discovery announcement message comprises computing an end-to-end link metric for the candidate end-to-end link to the remote UE based on the information about the associated wireless links of the one or more relay UEs and the candidate relay UE for the candidate end-to- end link to the remote UE and determining whether the candidate relay UE should transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to- end link. In one embodiment, the end-to-end link metric is a quality or performance related metric for the candidate end-to-end link to the remote UE.

[0016] In one embodiment, configuring the plurality of UEs comprises configuring one or more metric types to be reported for the associated wireless links. In one embodiment, the one or more metric types to be reported for the associated wireless links comprise any one or more of: Reference Signal Received Power (RSRP) for the associated wireless links, Reference Signal Received Quality ( RSRQ) for the associated wireless links, Signal to Noise Ratio (SNR) values for the associated wireless links, Signal to Interference plus Noise Ratio (SINR) for the associated wireless links, Received Strength of Signal Indicator (RSSI) for the associated wireless links, latency for the associated wireless links, capacity for the associated wireless links, congestion for the associated wireless links, and energy status for the associated wireless links. In one embodiment, the information about the associated wireless links received from the plurality of UEs comprises metric values for the one or more metric types.

[0017] In one embodiment, configuring the plurality of UEs comprises configuring how one or more metrics to be reported for the associated wireless links are to be calculated.

[0018] In one embodiment, the controlling entity is a network node, and the candidate end- to-end link from the controlling entity to the remote UE is a candidate multi-hop UE-to-Network (U2N) link. [0019] In one embodiment, the controlling entity is a source or destination remote UE, and the candidate end-to-end link from the controlling entity to the remote UE is a candidate multihop UE-to-UE (U2U) link.

[0020] Corresponding embodiments of a controlling entity for multi-hop sidelink communication are also disclosed. In one embodiment, a controlling entity for multi-hop sidelink communication comprises processing circuitry configured to cause the controlling entity to configure a plurality of UEs to report information about associated wireless links. The associated wireless links comprises associated sidelinks and, if any, direct wireless links to a network node. The plurality of UEs comprise one or more relay UEs and a candidate relay UE for candidate end-to-end link from the controlling entity to a remote UE, the candidate end-to- end link comprising a candidate multi-hop sidelink to a remote UE via the one or more relay UEs and the candidate relay UE. The processing circuitry is further configured to cause the controlling entity to receive the information about the associated wireless links from the plurality of UEs, determine whether the candidate relay UE should transmit a discovery announcement message based on the information about the associated wireless links of the one or more relay UEs and the candidate relay UE (604) for the candidate end-to-end link to the remote UE, and transmit, directly or indirectly to the candidate relay UE, an indication of a result of the determining.

[0021] Embodiments of a method performed by a candidate relay UE are also disclosed. In one embodiment, a method performed by a candidate relay UE comprises receiving, directly or indirectly from a controlling entity, information that configures the candidate relay UE to report information about one or more associated wireless links, wherein the one or more associated wireless links comprises at least one associated sidelinks and, if any, a direct wireless link to a network node. The method further comprises transmitting, directly or indirectly to the controlling entity, the information about the one or more associated wireless links. The method further comprises receiving, directly or indirectly from the controlling entity, an indication of whether the candidate relay UE should or is permitted to transit a discovery announcement and operating in accordance with the received indication.

[0022] In one embodiment, the indication is an indication for the candidate relay UE to transmit a discovery announcement message, and operating in accordance with the received indication comprises transmitting a discovery announcement message responsive to receiving the indication.

[0023] Corresponding embodiments of a candidate relay UE are also disclosed. In one embodiment, a candidate relay UE comprises a communication interface and processing circuity associated with the communication interface. The processing circuitry is configured to cause the candidate relay UE to receive, directly or indirectly from a controlling entity, information that configures the candidate relay UE to report information about one or more associated wireless links, wherein the one or more associated wireless links comprises at least one associated sidelinks and, if any, a direct wireless link to a network node. The processing circuitry is further configured to cause the candidate relay UE to transmit, directly or indirectly to the controlling entity, the information about the one or more associated wireless links. The processing circuitry is further configured to cause the candidate relay UE to receive, directly or indirectly from the controlling entity, an indication of whether the candidate relay UE should or is permitted to transit a discovery announcement and operate in accordance with the received indication.

[0024] In one embodiment, a method performed by a candidate relay UE for a candidate end- to-end link to a remote UE that comprises a candidate multi-hop sidelink comprises receiving information about wireless links associated to one or more relay UEs and/or one or more other candidate relay UEs in the candidate end-to-end link to the remote UE. The method further comprises determining whether to transmit a discovery announcement message based on the received information about the wireless links associated to the one or more relay UEs and/or the one or more other candidate relay UEs in the candidate end-to-end link to the remote UE and operating in accordance with a result of the determining.

[0025] In one embodiment, determining whether to transmit a discovery announcement message comprises computing an end-to-end link metric for the candidate end-to-end link to the remote UE based on the received information about the wireless links associated to the one or more relay UEs and/or the one or more other candidate relay UEs in the candidate end-to-end link to the remote UE and information about one or more associated sidelinks of the candidate relay UE. Determining whether to transmit a discovery announcement message further comprises determining whether to transmit a discovery announcement message based on the end- to-end link metric for the candidate end-to-end link.

[0026] In one embodiment, the method further comprises receiving, directly or indirectly from a controlling entity, information that configures the candidate relay UE with one or more thresholds and/or criteria for determining whether to transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to-end link. Determining whether to transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to-end link comprises determining whether to transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to-end link and the one or more thresholds and/or criteria. In one embodiment, the method further comprises receiving, directly or indirectly from the controlling entity, information that configures the candidate relay UE on the type of end-to-end link metric to be computed, how to compute the end-to-end link metric, or both.

[0027] In one embodiment, the candidate end-to-end link is a candidate end-to-end link from a controlling entity to the remote UE, the controlling entity is a network node, and the candidate end-to-end link from the controlling entity to the remote UE is a candidate multi-hop U2N link. [0028] In one embodiment, the candidate end-to-end link is a candidate end-to-end link from a controlling entity to the remote UE, the controlling entity is a source or destination UE, and the candidate end-to-end link from the controlling entity to the remote UE is a candidate multi-hop U2U link.

[0029] Corresponding embodiments of a candidate relay UE are also disclosed. In one embodiment, a candidate relay UE for a candidate end-to-end link to a remote UE that comprises a candidate multi-hop sidelink comprises a communication interface and processing circuity associated with the communication interface. The processing circuitry is configured to cause the candidate relay UE to receive information about wireless links associated to one or more relay UEs and/or one or more other candidate relay UEs in the candidate end-to-end link to the remote UE, determine whether to transmit a discovery announcement message based on the received information about the wireless links associated to the one or more relay UEs and/or the one or more other candidate relay UEs in the candidate end-to-end link to the remote UE, and operate in accordance with a result of the determining.

[0030] In one embodiment, a method performed by a controlling entity for a candidate end- to-end link to a remote UE that comprises a candidate multi-hop sidelink comprises transmitting, directly or indirectly to candidate relay UE for the candidate multi-hop link, information about wireless links associated to one or more relay UEs and/or one or more other candidate relay UEs in the candidate end-to-end link.

[0031] In one embodiment, the method further comprises transmitting, directly or indirectly to the candidate relay UE, information that configures the candidate relay UE with one or more thresholds and/or criteria for determining whether to transmit a discovery announcement message based on the information about the wireless links associated to the one or more relay UEs and/or the one or more other candidate relay UEs in the candidate end-to-end link.

[0032] In one embodiment, the method further comprises transmitting, directly or indirectly to the candidate relay UE, information that configures the candidate relay UE on a type of end- to-end link metric to be computed for the candidate end-to-end link, how to compute the end-to- end link metric, or both. [0033] Corresponding embodiments of a controlling entity are also disclosed. In one embodiment, a controlling entity for a candidate end-to-end link to a remote UE that comprises a candidate multi-hop sidelink comprises processing circuitry configured to cause the controlling entity to transmit, directly or indirectly to candidate relay UE for the candidate multi-hop link, information about wireless links associated to one or more relay UEs and/or one or more other candidate relay UEs in the candidate end-to-end link.

Brief Description of the Drawings

[0034] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0035] Figure 1 is a reproduction of Figure A.2.1-1 of Third Generation Partnership Project (3GPP) Technical Report (TR) 23.752 V17.0.0;

[0036] Figure 2 is a reproduction of Figure A.2.2-1 of 3GPP TR 23.752;

[0037] Figure 3 is a reproduction of Figure 4.5.5.1-1 of 3GPP TR 38.836 V17.0.0;

[0038] Figure 4 depicts an example embodiment of a wireless system including an Access

Node (AN) and a number of User Equipments (UEs) including a remote UE and a number of Sidelink (SE) UE-to-Network (U2N) UEs;

[0039] Figure 5 depicts an example embodiment of a wireless system including a number of UEs including a source or destination UE, a remote UE, and a number of SL UE-to-UE (U2U) UEs;

[0040] Figure 6 illustrates the operation of a controlling entity (e.g., a network node in the case of a U2N relay scenario or a remote UE in the case of a U2U relay scenario) of a wireless system, a relay UE having a link (e.g., a Uu link or PC5 link) to the controlling entity, a candidate relay UE, and a remote UE, in accordance with embodiments of the present disclosure; [0041] Figure 7 illustrates the operation of a controlling entity (e.g., a network node in the case of a U2N relay scenario or a remote UE in the case of a U2U relay scenario) of a wireless system, a relay UE having a link (e.g., a Uu link or PC5 link) to the controlling entity, a candidate relay UE, and a remote UE, in accordance with other embodiments of the present disclosure;

[0042] Figure 8 shows an example of a communication system in accordance with some embodiments;

[0043] Figure 9 shows a UE in accordance with some embodiments;

[0044] Figure 10 shows a network node in accordance with some embodiments; [0045] Figure 11 is a block diagram of a host, which may be an embodiment of the host of Figure 8, in accordance with various aspects described herein;

[0046] Figure 12 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized; and

[0047] Figure 13 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments.

Detailed Description

[0048] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments.

Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0049] There currently exist certain challenge(s). In the current New Radio (NR) standard, a remote User Equipment (UE) performs sidelink discovery and relay establishment procedures when a defined condition is met:

• based on the quality of the existing PC5 links in terms of metrics (e.g., Sidelink (SL) Reference Signal Received Power (RSRP) (i.e., SL-RSRP) or SL discovery RSRP (SD- RSRP)) for the remote UE which is out of coverage from any NR base station (gNB). Any PC5 link in the measurement contains only one hop.

• based on the quality of the Uu link between the remote UE and a gNB in terms of metrics e.g., RSRP, Reference Signal Received Quality (RSRQ), Received Strength of Signal Indicator (RSSI), Signal to Interference plus Noise Ratio (SINR), Signal to Interference Ratio (SIR), etc. for the remote UE which has network coverage to a gNB.

[0050] In a multi-hop sidelink relaying assisted network, there may be cases where the direct link between a remote UE and a relay UE is good, but the rest of the wireless links between the relay UE and its destination node (another relay UE or a gNB) is bad. In these cases, the existing sidelink discovery and relay establishment procedure can result in a bad end-to-end wireless path selection for the remote UE since the procedure only considers per hop metrics, and thereby reduce the success rate and increase the latency of sidelink relay establishment for the remote UE. This is because the network may only be aware of what is happening in the direct Uu link towards the remote UE but may not be aware of what is the quality of the link(s) between the remote UE and one (or more) relay UE(s). The current framework, standardized during Release 17, implies that measurements are performed by the UE per-hop and thus there is no estimate of the overall quality of relay UE that includes the PC5 and Uu hops.

[0051] Embodiments of the present disclosure attempt to avoid remote UEs from transmitting discovery messages without first ensuring that the quality of end-to-end sidelink link is sufficient. By doing so, bad Quality of Service (QoS), bad Quality of Experience (QoE), and/or service disruptions can be avoided.

[0052] Note that signaling and mechanisms for end-to-end path selection and reselection in network-node-based relaying networks have been considered. Furthermore, new signaling and mechanisms for both network-triggered and UE-triggered mobility in multi-hop U2N sidelink scenarios have been considered.

[0053] However, the current design and behaviors of the discovery message transmitted by the relay UE during discovery procedure does not capture the end-to-end quality of the multi-hop sidelink relay link. That is, it is possible that the end-to-end quality of such link is inadequate, yet the remote UE may announce itself to the remote UE based only on the quality of its Uu link. Hence, new behaviors and signaling and mechanisms are needed to address this problem in sidelink relaying scenarios.

[0054] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. From a network standpoint, embodiments of systems and methods are disclosed that provide new behaviors and signaling such that a relay UE is provided with minimum and maximum thresholds or criteria that capture the complete multi-hop sidelink link quality or performance in the link between the network node and the candidate relay UE via other relay UEs in the multi-hop sidelink scenario.

[0055] From a relay UE standpoint, embodiments of systems and methods are disclosed that provide new behaviors and signaling such that the remote UE can obtain sidelink link related information of the end-to-end wireless path performance, based on which a discovery and/or a relay establishment decision will be made.

[0056] The decision related to whether a relay UE is able to transmit a discovery message can be made either directly by the network node based on the information received from relay nodes or by the relay UE itself according to information received from the network node via relay UEs, if any.

[0057] Embodiments of systems and methods that provide new behaviors and signaling between a network and a relay UE to enable the relay UE to determine whether it is allowed to transmit a discovery message. The provided new/signaling captures information about the end- to-end wireless link quality or performance that the relay UE is associated to via other relay UEs, if any.

[0058] Remote UEs are not involved in embodiments of the proposed solution. Yet, the proposed solution has the goal of guaranteeing remote UEs performance if a multi-hop UE-to- Network (U2N) sidelink link is to be established.

[0059] Certain embodiments may provide one or more of the following technical advantage(s). Embodiments of the proposed solution may ensure good end-to-end wireless multi-hop sidelink link performance or quality before a relay UE makes itself available to remote UEs by transmitting a discovery message.

[0060] Compared to the existing procedures, embodiments of the proposed solution can help avoid a relay UE transmitting a discovery message if the performance of the sidelink link between the relay UE and the network node via other relay nodes, if any, fulfils end-to-end criteria. In this way, it may reduce the latency and unnecessary signaling overhead in case a remote UE anyway needs to be redirected/handover to another access node and/or relay UE due to intermediate link quality issues.

[0061] Embodiments of the systems and methods disclosed herein refer to the NR Radio Access Technology (RAT) but can be applied also to Long Term Evolution (LTE) RAT or any other RAT enabling direct communication between two (or more) nearby devices without any loss of meaning.

[0062] Further, to the term “RM UE” is sometimes used herein to refer to the remote UE that is able to transmit and/or receive packets from/to the network node (e.g., base station such as, e.g., gNB for NR) via an intermediate mobile terminal (UE-to-Network (U2N) relay UE) that we refer to as “relay UE” or “RL UE”.

[0063] The link or radio link over which the signals are transmitted between at least two UEs for Device-to-Device (D2D) operation is referred to herein as the sidelink (SL). The signals transmitted between the UEs for D2D operation are referred to herein as SL signals. The term “SL” may also interchangeably be called a D2D link, Vehicle to Anything (V2X) link, pro-se link, peer-to-peer link, PC5 link, etc. The SL signals may also interchangeably be called V2X signals, D2D signals, pro-se signals, PC5 signals, peer-to-peer signals, etc.

[0064] Further, even if the embodiments target the sidelink relay scenarios, each method and solution described below can also be applied without any loss of meaning to normal sidelink operation where two UEs are involved in sidelink operation with or without the involvement of the network. [0065] Also, embodiments related to the entity in the system that configures and sends signaling to the relay UE can be applied without any loss of meaning to the network node, the source remote UE, or the destination remote UE.

[0066] As used herein, a “candidate sidelink” is a sidelink between two UEs (e.g., a relay UE and another relay UE or between a relay UE and a remote UE) that is being considered for use as part of an end-to-end link to a remote UE.

[0067] Also note that, as used herein, the term “end-to-end link” is a multi-hop wireless link from a source or destination node (e.g., a network node of a wireless network such as, e.g., a base station in the case of U2N relay or source or destination remote UE) to a remote UE.

[0068] As used herein, a “candidate end-to-end link” is an end-to-end link that includes at least one candidate sidelink.

[0069] As used herein, a “multi-hop sidelink” is a wireless link to a remote UE that passes through two or more relay UEs.

[0070] As used herein, a “candidate multi-hop sidelink” is a multi-hop sidelink to a remote UE that includes at least one candidate sidelink.

[0071] Figure 4 depicts an example embodiment of a wireless system including an Access Node (AN) (e.g., a gNB or gNB Distributed Unit (gNB-DU)) and a number of UEs including a remote UE and a number of SL U2N UEs UE1, UE2, and UE3. In this illustrated example, UE1 is a relay UE and thus sometimes referred to herein as relay UE1, and UE2 and UE3 are candidate relay UEs and thus sometimes referred to herein as candidate relay UE2 and candidate relay UE3. In the following, the description focuses on exemplifying how relay UE1 becomes a relay UE for UE2, how relay UE2 becomes a candidate relay UE for the remote UE, and how relay UE3 becomes a candidate relay for the remote UE. In the case of relay UE1 and relay UE3, as specified in the current standard, relay UE1 and relay UE3 must check if the signal strength of their respective Uu links to the AN satisfy the minimum and maximum thresholds/criteria(s), if provided by the AN, before relay UE1 and/or relay UE3 can transmit a discovery message. In the depicted example, both relay UE1 and relay UE3 satisfy the criteria and become a candidate relay UE. Furthermore, let’s assume that relay UE1 and relay UE2 establish a SL U2N relay link following the steps as provided in the current NR standard. After this SL U2N relay link between relay UE1 and relay UE2 is established, in the case of relay UE2, relay UE2 needs to verify that the multi-hop sidelink signal strength is within the minimum and maximum multi-hop sidelink thresholds/criteria, if provided by the AN, before relay UE2 can transmit a discovery message and hence become a candidate relay UE to the remote UE. That is, relay UE2 combines the current or predicted per-link quality/performance of all the wireless links between relay UE2 and the AN, i.e., the Uu link between relay UE1 and the AN and the SL U2N relay link (i.e., the sidelink or PC5 link) between relay UE1 and relay UE2. For this, relay UE2 follows the procedures, instructions, or behaviors, as described in the embodiments of the present disclosure, i.e., which metric, indicator, and scale to use whether specified by the network node or not. [0072] Figure 5 depicts another example of a wireless system that includes multiple UEs (remote UE and SL UE-to-UE (U2U) relays UEO, UE1, UE2, and UE3). In a manner similar to the U2N case in Figure 1 , relay UE2 and relay UE3 must ensure that the end-to-end link quality is sufficient before transmitting a discovery message and hence announcing themselves to the remote UE.

[0073] Now, a description of embodiments of a method for relay UE discovery message transmission in a multi-hop U2N (or UE-to-UE (U2U)) sidelink scenario will be provided. The embodiments described in the following describe new methods by both an entity of the wireless system and a relay UE for the relay UE to determine whether it can transmit a discovery message or not based on new end-to-end wireless sidelink link quality/performance criteria.

[0074] The entity in the wireless system may be, e.g., a network node (e.g., the AN of the example of Figure 4 or source remote UE in the example of Figure 5). From the perspective of the entity in the wireless system that configures measurement or configuration at the relay UE, new behaviors and signaling need to be considered such that a relay UE is provided with minimum and maximum thresholds/criteria that capture the complete multi-hop sidelink link quality/performance in the link between the entity of the wireless system to the candidate relay UE via other relay UEs in the multi-hop sidelink scenario.

[0075] In an embodiment, an entity of the wireless system may provide the relay UE with minimum and maximum multi-hop sidelink thresholds and/or criteria(s) (denoted herein as “thresholds/criteria(s)”) that must be fulfilled before the relay UE transmits a discovery message, e.g., when in idle (e.g., RRC_IDLE) or inactive (RRC_INACTIVE) state. The multi-hop sidelink minimum and maximum thresholds are based on the current or predicted end-to-end link quality and/or performance, e.g., by combining current or predicted quality and/or performance information of all links in the multi-hop sidelink path, where this multi-hop sidelink includes at least a link (Uu link or PC5 link) between a first endpoint node (e.g., an or a remote UE) and a first relay UE, a PC5 link between the first relay UE and a second relay UE, and a PC5 link between the second relay UE and remote UE (i.e., the second endpoint). The multi-hop sidelink may optionally include one or more additional relay UEs and their associated PC5 links between the first relay UE and the second relay UE. Thus, the multi-hop sidelink minimum and maximum thresholds are based on the current or predicted end-to-end link quality and/or performance, e.g., by combining current or predicted quality or performance information of: (1) the Uu link between the AN (e.g., gNB) and the first relay UE in the case of U2N relay, (2) the PC5 link between a first remote UE and the first relay UE in the case of U2U relay, (3) the (second) remote UE and a last relay UE (i.e., the relay UE having a PC5 link with the destination remote UE, and (4) all the PC5 links between relay UEs in the multi-hop sidelink path, if any. [0076] In an embodiment, the entity of the wireless system can be a network node (i.e., in case of U2N scenario), a destination remote UE (i.e., in case of U2U scenario), or a source remote UE (i.e., in case of U2U scenario).

[0077] In an embodiment, in order to combine current or predicted quality and/or performance information of the Uu and (multiple) PC5 links, or only between multiple PC5 links, there is information exchange between the entity of the wireless system and relay UE, which may potentially be via relay UEs, if any.

[0078] In an embodiment, new behaviors and signaling from an entity of the wireless system for configuring the relay UE(s) to measure and report sidelink-related measurement results back to the entity of the wireless system either directly or via other relay UE(s). The signaling (i.e., the reported measurement results) includes information related to the end-to-end performance/quality of a multi-hop sidelink relay link.

[0079] In an embodiment, the entity of the wireless system evaluates whether the relay UE is permitted to transmit a discovery message based on the information reported by the relay UE(s) and, after, transmit the decision to the relay node. Alternatively, the entity of the wireless system shares the reported information with the relay UE, and the relay UE evaluates whether it fulfills the criteria.

[0080] In a sub-embodiment, the multi-hop sidelink minimum and maximum thresholds to be used by a relay UE are broadcasted in system information (e.g., in System Information Block (SIB) 1 (i.e., SIB1) or the Master Information Block (MIB) by the entity of the wireless system.

[0081] In another sub-embodiment, the multi-hop sidelink minimum and maximum thresholds are transmitted by the entity of the wireless system using dedicated direct signaling (e.g., Radio Resource Control (RRC) signaling, MAC CE signaling, or a combination thereof). [0082] If the entity of the wireless system performs the evaluation, then the entity of the wireless system derives a multi-hop (e.g., from AN to relay UE or from source/destination remote UE, via intermediate relay UEs if any) sidelink quality/performance metric using per-link quality/performance indicators (e.g., received from the entity of the wireless system). If the relay UE performs the evaluation, then in one embodiment, the relay UE derives the multi-hop (e.g., from AN to relay UE or from source/destination remote UE, via intermediate relay UEs if any) sidelink quality/performance metric using per-link quality/performance indicators (e.g., received from the entity of the wireless system). Note that the quality/performance indicators may be expressed in linear or logarithmic (decibels) scale.

[0083] The multi-hop sidelink quality/performance metric derived by controlling entity or the relay UE for evaluating if the relay UE can transmit a discovery message can be, e.g., a minimum value, a maximum value, a mean value, a weighted average value, a harmonic mean value.

[0084] In another embodiment, the entity of the wireless system may specifically instruct the relay UE which multi-hop sidelink quality/performance metric to derive by explicitly including this instruction.

[0085] In an embodiment, the decision related to which specific multi-hop sidelink quality/performance metric must be derived by controlling entity or the relay UE may be made by the entity of the wireless system and, if needed, transmitted to the relay UE. This means that the relay UEs transmit all the measurements on each link/hop and then the entity of the wireless system combines them. In a sub-embodiment, the decision above may be made by the entity of the wireless system based on, e.g., the service type, the UE type, or the like. In another subembodiment, if the evaluation of whether the relay UE is to transmit a discovery message is made at the relay UE, the instruction about which specific multi-hop sidelink quality/performance metric is to be used may be transmitted to the relay UE together with the multi-hop sidelink minimum and maximum thresholds/criteria described above. In a subembodiment, the information related to which specific multi-hop sidelink quality/performance metric must be derived by the relay UE may be transmitted by the entity of the wireless system using, e.g., an integer value according to tabulated values known to both entity of the wireless system and relay UE.

[0086] The per-link quality/performance indicators to be used in deriving the multi-hop sidelink quality/performance metric can be, e.g., an RSRP value, an RSRQ value, an SNR value, an SINR, an RSSI, a latency value, a capacity value (capturing both SNR and bandwidth), a congestion value, an energy status value.

[0087] In another embodiment, if the evaluation of whether the relay UE is to transmit a discovery message is made at the relay UE, the entity of the wireless system may specifically instruct the relay UE which performance indicator above shall be used by the relay UE to calculate the end-to-end metric by explicitly including this information together with the multihop sidelink minimum and maximum thresholds/criteria.

[0088] In an embodiment, if the evaluation of whether the relay UE is to transmit a discovery message is made at the relay UE, the decision related to which specific multi-hop sidelink quality/performance metric must be derived by the relay UE may be made by the entity of the wireless system and transmitted to the relay UE. This means that, in one embodiment, the relay UE(s) transmits all the indicators in the measurements on each link/hop and then is the network that combine them. Note that only one of the two relay UEs involved with a particular sidelink needs to transmit measurement(s) to the entity in the wireless system. In a subembodiment, the decision may be made by the entity of the wireless system based on, e.g., the service type, the UE type.

[0089] In another sub-embodiment, the instruction about which performance indicator shall be used by the relay UE to calculate the end-to-end metric may be transmitted to the relay UE together with the multi-hop sidelink minimum and maximum thresholds/criteria described above. [0090] In a sub-embodiment, the information related to which specific quality/performance indicator must be used by the relay UE may be transmitted by the entity of the wireless system using an integer value according to tabulated values known to both entity of the wireless system and relay UE.

[0091] The multi-hop sidelink minimum and maximum thresholds can be transmitted by the entity of the wireless system to the relay UE using linear or decibel values where applicable, i.e., decibel values are applicable to RSRP, RSRQ, SNR, and SINR values and not applicable to latency, capacity, congestion value, or energy status values.

[0092] In another embodiment, the entity of the wireless system may specifically instruct the relay UE which scale, linear or decibel, is to be used to express the performance indicators when the relay UE is to calculate the multi-hop sidelink metric, e.g., by explicitly including this information together with the minimum and maximum thresholds/criteria.

[0093] In an embodiment, the decision related to which specific scale must be used by the relay UE may be made by the entity of the wireless system. In a sub-embodiment, the decision may be made by the entity of the wireless system based on, e.g., the service type, the UE type.

In another sub-embodiment, the instruction about which scale is to be used may be transmitted to the relay UE together with the multi-hop sidelink minimum and maximum thresholds/criteria described above.

[0094] In a sub-embodiment, the information related to which specific scale must be used by the relay UE may be transmitted by the entity of the wireless system using an integer value according to tabulated values known to both entity of the wireless system and relay UE.

[0095] From a relay UE standpoint, new behaviors and signaling are disclosed such that the remote UE can obtain sidelink link related information of the end-to-end wireless path performance and take this information into account to decide whether a discovery and/or a relay establishment decision will be made (e.g., to decide whether to transmit a discovery message). [0096] In an embodiment, a relay UE may read/decode, if provided by the network node, information/instruction(s) related to the minimum and maximum multi-hop sidelink thresholds/criteria(s) transmitted by the network node that must be fulfilled by the relay UE before it transmits a discovery message when in idle (e.g., RRC_IDLE) state, inactive (e.g., RRC_INACTIVE) state, or connected (e.g., RRC_CONNECTED) state.

[0097] In a sub-embodiment, the relay UE may read/decode the multi-hop sidelink minimum and maximum thresholds/criteria transmitted by the network node in a dedicated message (e.g., RRCReconfiguration, RRCResume, RRCSetup, or RRCReestablishment, or MAC CE, or PHY signaling).

[0098] In an embodiment, new behaviors and signaling from a relay UE to decode instructions from the network node and proceed as instructed, e.g., measuring sidelink link quality/performance and reporting back to the network node, transmitting sidelink link decision information to remote UE(s) either directly or via other relay UE(s) that are part of the sidelink link, if any.

[0099] In an embodiment, the relay node either decodes decision information sent by the network node about whether the relay UE may transmit a discovery message, or it may decode the end-to-end multi-hop sidelink link quality/performance information and perform the decision itself.

[0100] In an embodiment, the multi-hop sidelink quality/performance metric to be derived by the relay UE for evaluating if it can transmit a discovery message can be, e.g., a minimum value, a maximum value, a mean value, a weighted average value, a harmonic mean value.

[0101] In another embodiment, the relay UE may read/decode the information related to which specific quality/performance metric must be used if explicitly specified by the network node. In a sub-embodiment, an instruction about which specific quality/performance metric must be used may be read/decoded by the relay UE, e.g., in the message that includes the multihop sidelink minimum and maximum thresholds/criteria described above. In an embodiment, the relay UE may read/decode an integer value (according to tabulated values known to both network node and relay UE) which encapsulates the information related to which specific quality/performance indicator must be used by the relay UE. In an embodiment, if the information about which specific quality/performance metric must be used is not explicitly specified by the network node, the relay UE may follow a default behavior. In an embodiment, if the information about which specific quality/performance metric must be used is not explicitly specified by the network node, the relay UE may take the decision. In a sub-embodiment, this may be made by the relay UE based on, e.g., the service type, the UE type.

[0102] In an embodiment, the per-link quality/performance indicators to be used by the relay UE in deriving multi-hop sidelink quality/performance metric can be, e.g., an RSRP value, an RSRQ value, an SNR value, an SINR, a latency value, a capacity value (capturing both SNR and bandwidth such as, e.g., volume of free or available resources, achievable bit rate, achievable data throughput, or the like), a congestion value (e.g., channel/link busy ratio (CBR) or channel usage ratio, measured interference level, or the like), an energy status value (e.g., DRX active or inactive state, available or free transmitter power for the UE, or the like).

[0103] In another embodiment, the relay UE may read/decode the information related to which specific quality/performance indicator must be used if explicitly specified by the network node. In another sub-embodiment, the instruction about which specific quality/performance indicator must be used may be read/decoded by the relay UE, e.g., in the message that includes the multi-hop sidelink minimum and maximum thresholds/criteria described above. In an embodiment, the relay UE may read/decode an integer value (according to tabulated values known to both network node and relay UE) which encapsulates the information related to which specific quality/performance indicator must be used by the relay UE. In an embodiment, if the information related to which specific quality/performance indicator must be used by the relay UE is not explicitly specified by the network node, the relay UE may follow a default behavior. In an embodiment, if the information related to which specific quality/performance indicator must be used by the relay UE is not explicitly specified by the network node, the relay UE may make the decision. In a sub-embodiment, this decision may be made by the relay UE based on, e.g., the service type, the UE type.

[0104] In an embodiment, the multi-hop sidelink minimum and maximum thresholds can be transmitted by the network node to the relay UE using linear or decibel values where applicable, i.e., decibel values are applicable to RSRP, RSRQ, SNR, and SINR values and not applicable to latency, capacity, congestion value, or energy status values. In another embodiment, the relay UE may read/decode the information related to which specific scale must be used if explicitly specified by the network node. In another sub-embodiment, the instruction about which scale to use may be read/decoded by the relay UE, e.g., in the message that includes the multi-hop sidelink minimum and maximum thresholds/criteria described above. In an embodiment, the relay UE may read/decode an integer value (according to tabulated values known to both network node and relay UE) which encapsulates the information related to which specific scale must be used by the relay UE. In an embodiment, if the information related to which specific scale to use is not explicitly specified by the network node, the relay UE may follow a default behavior. In an embodiment, if the information related to which specific scale to use is not explicitly specified by the network node, the relay UE may make the decision. In a sub-embodiment, this decision may be made by the relay UE based on, e.g., the service type, the UE type.

[0105] In an embodiment, following a decision made by the network node, the relay UE may send a discovery message or start to monitor and receive a discovery message.

[0106] In an embodiment, following a decision made by the relay UE, the relay UE may send a discovery message or start to monitor and receive a discovery message.

[0107] In an embodiment, the relay UE may announce a discovery message e.g., based a Model A discovery procedure.

[0108] In an embodiment, the relay UE may send a discovery response message after reception of a discovery request/solicitation message sent by a remote UE, e.g., based Mode B discovery procedure.

[0109] In an embodiment, the relay UE is configured by the network with one or multiple measurement configurations wherein: a) At least one measurement configuration provides the relay UE with configuration regarding how to measure paths in terms of at least one multi-hop/E2E metric; b) At least one measurement configuration provides the relay UE with configuration regarding how to measure paths in terms of one or multiple per-hop metrics and derive multi-hop/E2E measurements based on per-hop measurements.

[0110] In an embodiment, upon reception of one or multiple measurement configurations, the relay UE performs measurements to paths including serving paths and non-serving paths in terms of at least one of the following metrics: a) One or multiple multi-hop/E2E metrics including e.g., QoS metrics in terms of packet latency, packet loss, packet error rate, ratio of packet retransmission, capacity metrics, congestion metrics, or energy status metrics, etc. b) one or multiple per-hop metrics and derive multi-hop/E2E measurements based on per- hop measurements. Per-hop metrics may comprise radio signa quality in terms of RSRP, RSRQ, SNR, and SINR values, QoS metrics in terms of packet latency, packet loss, packet error rate, ratio of packet retransmission, capacity metrics, congestion metrics, or energy status metrics etc.

[0111] In an embodiment, the relay UE performs measurements in one of the following fashions a) Periodically b) Event triggered. c) Upon reception of a request message from the gNB or another UE

[0112] Figure 6 illustrates the operation of a controlling entity 600 (e.g., a network node such as, e.g., a gNB in the case of a U2N relay scenario or a remote UE in the case of U2U relay scenario) of a wireless system, a relay UE 602 having a link (e.g., a Uu link or PC5 link) to the controlling entity 600, a candidate relay UE 604, and a remote UE 606, in accordance with at least some of the embodiments described above. In this example, there is a candidate end-to-end link that includes a candidate multi-hop sidelink to the remote UE 606 via the relay UE 602 and the candidate relay UE 604, and the controlling entity 600 makes a decision about whether the candidate relay UE 604 is to transmit a discovery message so as to be discoverable by the remote UE 606, where this decision is based on an end-to-end link metric for the candidate end-to-end link between the controlling entity 600 and the remote UE 606, which includes a candidate multihop sidelink. The end-to-end link metric for the candidate end-to-end link is a metric that is based on quality or performance metrics for the individual links within the candidate end-to-end link which in the example of Figure 6 include the link (Uu or PC5) between the relay UE 602 and the controlling entity 600, the sidelink between the relay UE 602 and the candidate relay UE 604, and the (candidate) sidelink between the candidate relay UE 604 and the remote UE 606.

[0113] More specifically, as illustrated in Figure 6, the controlling entity 600 configures the relay UE 602 and the candidate relay UE 604 to report information about the associated (side)links, as described above (step 608). This configuration may include a configuration of the types of measurements, or indicators, or be reported (e.g., RSRP, RSRQ, SNR, capacity, etc., as described above). This configuration may be made via system information or dedicated signaling. Based on the configuration, the relay UE 602 and the candidate relay UE 604 send, directly or indirectly to the controlling entity 600, information about the associated (side)links (step 610).

[0114] Based on the received information, the controlling entity 600 decides whether the candidate relay UE 604 should transmit a discovery announcement so as to be discovered by the remote UE 606 (step 612). More specifically, in one embodiment as described above, the controlling entity 600 computes an end-to-end link metric for the candidate end-to-end link (including the candidate multi-hop sidelink) from the controlling entity 600 to the remote UE 606 via the relay UE 602 and the candidate relay UE 604 based on the received information (step 612A). This end-to-end link metric may be a metric that is indicative of an actual or predicted performance or quality of the candidate end-to-end link. The details of various embodiments of this metric and how it is computed are described above and are equally applicable here. The controlling entity 600 then decides whether the candidate relay UE 604 should transmit a discovery announcement based on the computed end-to-end link metric (step 612B).

[0115] The controlling entity 600 transmits, indirectly or directly to the candidate relay UE 604, an indication that indicates a result of the decision of step 612 (i.e., an indication that indicates whether the candidate relay UE 604 should or is permitted to transmit a discovery announcement) (step 614). The candidate relay UE 604 then operates in accordance with the received indication (step 616). For example, the candidate relay UE 604 transmits a discovery announcement if the indication indicates that it should do so; otherwise, the candidate relay UE 604 refrains from transmitting a discovery announcement message.

[0116] Figure 7 illustrates the operation of a controlling entity 700 (e.g., a network node such as, e.g., a gNB in the case of a U2N relay scenario or a remote UE in the case of U2U relay scenario) of a wireless system, a relay UE 702 having a link (e.g., a Uu link or PC5 link) to the controlling entity 700, a candidate relay UE 704, and a remote UE 706, in accordance with at least some of the embodiments described above. In this example, there is a candidate end-to-end link that includes a candidate multi-hop sidelink to the remote UE 706 via the relay UE 702 and the candidate relay UE 704, and the candidate relay UE 704 makes a decision about whether the candidate relay UE 704 is to transmit a discovery message so as to be discoverable by the remote UE 706, where this decision is based on an end-to-end link metric for the candidate end-to-end link between the controlling entity 700 and the remote UE 706, which includes a candidate multihop sidelink. The end-to-end link metric for the candidate end-to-end link is a metric that is based on quality or performance metrics for the individual links within the candidate end-to-end link which in the example of Figure 7 include the link (Uu or PC5) between the relay UE 702 and the controlling entity 700, the sidelink between the relay UE 702 and the candidate relay UE 704, and the (candidate) sidelink between the candidate relay UE 704 and the remote UE 706.

[0117] More specifically, as illustrated in Figure 7, the controlling entity 700 configures the relay UE 702 and the candidate relay UE 704 to report information about the associated (side)links, as described above (step 708). This configuration may include a configuration of the types of measurements, or indicators, or be reported (e.g., RSRP, RSRQ, SNR, capacity, etc., as described above). This configuration may be made via system information or dedicated signaling. The controlling entity 700 also configures the candidate relay UE 704 with one or more thresholds (e.g., minimum and/or maximum threshold(s)) and/or criteria for determining whether the candidate relay UE 704 is to transmit a discovery announcement based on an end-to- end metric for the (candidate) multi-hope sidelink (step 710). As discussed above, the controlling entity 700 may also configure the candidate relay UE 704 with additional information, as described above (step 712). This additional information may include, for example, a type of end-to-end link metric to be computed for the candidate end-to-end link (e.g., RSRP, RSRQ, SNR, capacity, or the like), how the end-to-end link metric is to be computed (e.g., min, max, average, weighted average, or the like), a scale to be used for the end-to-end link metric (e.g., linear or decibel), or the like.

[0118] Based on the configuration of step 708, the relay UE 702 and the candidate relay UE 704 send, directly or indirectly to the controlling entity 700, information about the associated (side)links (step 714). Note that this information may also depend on the configuration of step 712 (e.g., reported measurements are those needed for computing the end-to-end metric).

[0119] In this embodiment, the controlling entity 700 sends at least some of the received information about the (side)links to the candidate relay UE 704 (step 716). Note that, in one alternative embodiment, the candidate relay UE 704 does not report information in step 714 but stores the obtained information about its associated sidelinks for later use when computing the end-to-end link metric. Using the information about all of the (side)links in the candidate end-to- end link, the candidate relay UE 704 decides whether to transmit an announcement message (step 718). More specifically, in one embodiment, the candidate relay UE 704 computes the end-to- end link metric for the candidate end-to-end link based on the information about all of the (side)links in the candidate end-to-end link as described above (step 718 A) and decides whether to transmit an announcement message based on the computed end-to-end link metric and the threshold(s) or criteria configured in step 710 (step 718B). The candidate relay UE 604 then operates in accordance with the decision (step 720). For example, the candidate relay UE 604 transmits a discovery announcement if it has decided that it should do so; otherwise, the candidate relay UE 604 refrains from transmitting a discovery announcement message.

[0120] Figure 8 shows an example of a communication system 800 in accordance with some embodiments.

[0121] In the example, the communication system 800 includes a telecommunication network 802 that includes an access network 804, such as a Radio Access Network (RAN), and a core network 806, which includes one or more core network nodes 808. The access network 804 includes one or more access network nodes, such as network nodes 810A and 810B (one or more of which may be generally referred to as network nodes 810), or any other similar Third Generation Partnership Project (3GPP) access node or non-3GPP Access Point (AP). The network nodes 810 facilitate direct or indirect connection of User Equipment (UE), such as by connecting UEs 812A, 812B, 812C, and 812D (one or more of which may be generally referred to as UEs 812) to the core network 806 over one or more wireless connections. [0122] Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 800 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. The communication system 800 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.

[0123] The UEs 812 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes 810 and other communication devices. Similarly, the network nodes 810 are arranged, capable, configured, and/or operable to communicate directly or indirectly with the UEs 812 and/or with other network nodes or equipment in the telecommunication network 802 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in the telecommunication network 802.

[0124] In the depicted example, the core network 806 connects the network nodes 810 to one or more hosts, such as host 816. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 806 includes one more core network nodes (e.g., core network node 808) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 808. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-Concealing Function (SIDE), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF).

[0125] The host 816 may be under the ownership or control of a service provider other than an operator or provider of the access network 804 and/or the telecommunication network 802, and may be operated by the service provider or on behalf of the service provider. The host 816 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio/video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0126] As a whole, the communication system 800 of Figure 8 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system 800 may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and/or other suitable Second, Third, Fourth, or Fifth Generation (2G, 3G, 4G, or 5G) standards, or any applicable future generation standard (e.g., Sixth Generation (6G)); Wireless Local Area Network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any Low Power Wide Area Network (LPWAN) standards such as LoRa and Sigfox.

[0127] In some examples, the telecommunication network 802 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunication network 802 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 802. For example, the telecommunication network 802 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing enhanced Mobile Broadband (eMBB) services to other UEs, and/or massive Machine Type Communication (mMTC)/massive Internet of Things (loT) services to yet further UEs.

[0128] In some examples, the UEs 812 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 804 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 804. Additionally, a UE may be configured for operating in single- or multi-Radio Access Technology (RAT) or multi-standard mode. For example, a UE may operate with any one or combination of WiFi, New Radio (NR), and LTE, i.e. be configured for Multi-Radio Dual Connectivity (MR-DC), such as Evolved UMTS Terrestrial RAN (E-UTRAN) NR - Dual Connectivity (EN-DC).

[0129] In the example, a hub 814 communicates with the access network 804 to facilitate indirect communication between one or more UEs (e.g., UE 812C and/or 812D) and network nodes (e.g., network node 810B). In some examples, the hub 814 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 814 may be a broadband router enabling access to the core network 806 for the UEs. As another example, the hub 814 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 810, or by executable code, script, process, or other instructions in the hub 814. As another example, the hub 814 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 814 may be a content source. For example, for a UE that is a Virtual Reality (VR) headset, display, loudspeaker or other media delivery device, the hub 814 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 814 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, the hub 814 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0130] The hub 814 may have a constant/persistent or intermittent connection to the network node 81 OB. The hub 814 may also allow for a different communication scheme and/or schedule between the hub 814 and UEs (e.g., UE 812C and/or 812D), and between the hub 814 and the core network 806. In other examples, the hub 814 is connected to the core network 806 and/or one or more UEs via a wired connection. Moreover, the hub 814 may be configured to connect to a Machine-to-Machine (M2M) service provider over the access network 804 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 810 while still connected via the hub 814 via a wired or wireless connection. In some embodiments, the hub 814 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to the network node 810B. In other embodiments, the hub 814 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and the network node 810B, but which is additionally capable of operating as a communication start and/or end point for certain data channels.

[0131] Figure 9 shows a UE 900 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged, and/or operable to communicate wirelessly with network nodes and/or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, Voice over Internet Protocol (VoIP) phone, wireless local loop phone, desktop computer, Personal Digital Assistant (PDA), wireless camera, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, Laptop Embedded Equipment (LEE), Laptop Mounted Equipment (LME), smart device, wireless Customer Premise Equipment (CPE), vehicle-mounted or vehicle embedded/integrated wireless device, etc. Other examples include any UE identified by the 3GPP, including a Narrowband Internet of Things (NB-IoT) UE, a Machine Type Communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.

[0132] A UE may support Device-to-Device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), Vehicle-to- Vehicle (V2V), Vehicle-to-Infrastructure (V2I), or Vehicle- to-Everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller).

Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0133] The UE 900 includes processing circuitry 902 that is operatively coupled via a bus 904 to an input/output interface 906, a power source 908, memory 910, a communication interface 912, and/or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 9. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0134] The processing circuitry 902 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 910. The processing circuitry 902 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 902 may include multiple Central Processing Units (CPUs).

[0135] In the example, the input/output interface 906 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and/or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 900. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device. [0136] In some embodiments, the power source 908 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 908 may further include power circuitry for delivering power from the power source 908 itself, and/or an external power source, to the various parts of the UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging the power source 908. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 908 to make the power suitable for the respective components of the UE 900 to which power is supplied.

[0137] The memory 910 may be or be configured to include memory such as Random Access Memory (RAM), Read Only Memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Electrically EPROM (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 910 includes one or more application programs 914, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 916. The memory 910 may store, for use by the UE 900, any of a variety of various operating systems or combinations of operating systems.

[0138] The memory 910 may be configured to include a number of physical drive units, such as Redundant Array of Independent Disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, High Density Digital Versatile Disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, Holographic Digital Data Storage (HDDS) optical disc drive, external mini Dual In-line Memory Module (DIMM), Synchronous Dynamic RAM (SDRAM), external micro-DIMM SDRAM, smartcard memory such as a tamper resistant module in the form of a Universal Integrated Circuit Card (UICC) including one or more Subscriber Identity Modules (SIMs), such as a Universal SIM (USIM) and/or Internet Protocol Multimedia Services Identity Module (ISIM), other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as a ‘SIM card.’ The memory 910 may allow the UE 900 to access instructions, application programs, and the like stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system, may be tangibly embodied as or in the memory 910, which may be or comprise a device-readable storage medium.

[0139] The processing circuitry 902 may be configured to communicate with an access network or other network using the communication interface 912. The communication interface 912 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 922. The communication interface 912 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 918 and/or a receiver 920 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 918 and receiver 920 may be coupled to one or more antennas (e.g., the antenna 922) and may share circuit components, software, or firmware, or alternatively be implemented separately.

[0140] In the illustrated embodiment, communication functions of the communication interface 912 may include cellular communication, WiFi communication, LPWAN communication, data communication, voice communication, multimedia communication, short- range communications such as Bluetooth, NFC, location-based communication such as the use of the Global Positioning System (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented according to one or more communication protocols and/or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband CDMA (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, Transmission Control Protocol/Internet Protocol (TCP/IP), Synchronous Optical Networking (SONET), Asynchronous Transfer Mode (ATM), Quick User Datagram Protocol Internet Connection (QUIC), Hypertext Transfer Protocol (HTTP), and so forth.

[0141] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 912, or via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0142] As another example, a UE comprises an actuator, a motor, or a switch related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0143] A UE, when in the form of an loT device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application, and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a television, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door/window sensor, a flood/moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or VR, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or itemtracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and/or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 900 shown in Figure 9.

[0144] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and/or measurements and transmits the results of such monitoring and/or measurements to another UE and/or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship, an airplane, or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.

[0145] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and/or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator and handle communication of data for both the speed sensor and the actuators.

[0146] Figure 10 shows a network node 1000 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged, and/or operable to communicate directly or indirectly with a UE and/or with other network nodes or equipment in a telecommunication network. Examples of network nodes include, but are not limited to, APs (e.g., radio APs), Base Stations (BSs) (e.g., radio BSs, Node Bs, evolved Node Bs (eNBs), and NR Node Bs (gNBs)).

[0147] BSs may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto BSs, pico BSs, micro BSs, or macro BSs. A BS may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio BS such as centralized digital units and/or Remote Radio Units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such RRUs may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio BS may also be referred to as nodes in a Distributed Antenna System (DAS).

[0148] Other examples of network nodes include multiple Transmission Point (multi-TRP) 5G access nodes, Multi-Standard Radio (MSR) equipment such as MSR BSs, network controllers such as Radio Network Controllers (RNCs) or BS Controllers (BSCs), Base Transceiver Stations (BTSs), transmission points, transmission nodes, Multi-Cell/Multicast Coordination Entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and/or Minimization of Drive Tests (MDTs).

[0149] The network node 1000 includes processing circuitry 1002, memory 1004, a communication interface 1006, and a power source 1008. The network node 1000 may be composed of multiple physically separate components (e.g., a Node B component and an RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 1000 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple Node Bs. In such a scenario, each unique Node B and RNC pair may in some instances be considered a single separate network node. In some embodiments, the network node 1000 may be configured to support multiple RATs. In such embodiments, some components may be duplicated (e.g., separate memory 1004 for different RATs) and some components may be reused (e.g., an antenna 1010 may be shared by different RATs). The network node 1000 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1000, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z- wave, Long Range Wide Area Network (LoRaWAN), Radio Frequency Identification (RFID), or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within the network node 1000.

[0150] The processing circuitry 1002 may comprise a combination of one or more of a microprocessor, controller, microcontroller, CPU, DSP, ASIC, FPGA, or any other suitable computing device, resource, or combination of hardware, software, and/or encoded logic operable to provide, either alone or in conjunction with other network node 1000 components, such as the memory 1004, to provide network node 1000 functionality.

[0151] In some embodiments, the processing circuitry 1002 includes a System on a Chip (SOC). In some embodiments, the processing circuitry 1002 includes one or more of Radio Frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014. In some embodiments, the RF transceiver circuitry 1012 and the baseband processing circuitry 1014 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of the RF transceiver circuitry 1012 and the baseband processing circuitry 1014 may be on the same chip or set of chips, boards, or units.

[0152] The memory 1004 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid state memory, remotely mounted memory, magnetic media, optical media, RAM, ROM, mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD), or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device-readable, and/or computer-executable memory devices that store information, data, and/or instructions that may be used by the processing circuitry 1002. The memory 1004 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and/or other instructions capable of being executed by the processing circuitry 1002 and utilized by the network node 1000. The memory 1004 may be used to store any calculations made by the processing circuitry 1002 and/or any data received via the communication interface 1006. In some embodiments, the processing circuitry 1002 and the memory 1004 are integrated.

[0153] The communication interface 1006 is used in wired or wireless communication of signaling and/or data between a network node, access network, and/or UE. As illustrated, the communication interface 1006 comprises port(s)/terminal(s) 1016 to send and receive data, for example to and from a network over a wired connection. The communication interface 1006 also includes radio front-end circuitry 1018 that may be coupled to, or in certain embodiments a part of, the antenna 1010. The radio front-end circuitry 1018 comprises filters 1020 and amplifiers 1022. The radio front-end circuitry 1018 may be connected to the antenna 1010 and the processing circuitry 1002. The radio front-end circuitry 1018 may be configured to condition signals communicated between the antenna 1010 and the processing circuitry 1002. The radio front-end circuitry 1018 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1018 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of the filters 1020 and/or the amplifiers 1022. The radio signal may then be transmitted via the antenna 1010. Similarly, when receiving data, the antenna 1010 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1018. The digital data may be passed to the processing circuitry 1002. In other embodiments, the communication interface 1006 may comprise different components and/or different combinations of components.

[0154] In certain alternative embodiments, the network node 1000 does not include separate radio front-end circuitry 1018; instead, the processing circuitry 1002 includes radio front-end circuitry and is connected to the antenna 1010. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1012 is part of the communication interface 1006. In still other embodiments, the communication interface 1006 includes the one or more ports or terminals 1016, the radio front-end circuitry 1018, and the RF transceiver circuitry 1012 as part of a radio unit (not shown), and the communication interface 1006 communicates with the baseband processing circuitry 1014, which is part of a digital unit (not shown).

[0155] The antenna 1010 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. The antenna 1010 may be coupled to the radio front-end circuitry 1018 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In certain embodiments, the antenna 1010 is separate from the network node 1000 and connectable to the network node 1000 through an interface or port.

[0156] The antenna 1010, the communication interface 1006, and/or the processing circuitry 1002 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by the network node 1000. Any information, data, and/or signals may be received from a UE, another network node, and/or any other network equipment. Similarly, the antenna 1010, the communication interface 1006, and/or the processing circuitry 1002 may be configured to perform any transmitting operations described herein as being performed by the network node 1000. Any information, data, and/or signals may be transmitted to a UE, another network node, and/or any other network equipment.

[0157] The power source 1008 provides power to the various components of the network node 1000 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1008 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1000 with power for performing the functionality described herein. For example, the network node 1000 may be connectable to an external power source (e.g., the power grid or an electricity outlet) via input circuitry or an interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1008. As a further example, the power source 1008 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0158] Embodiments of the network node 1000 may include additional components beyond those shown in Figure 10 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, the network node 1000 may include user interface equipment to allow input of information into the network node 1000 and to allow output of information from the network node 1000. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1000.

[0159] Figure 11 is a block diagram of a host 1100, which may be an embodiment of the host 816 of Figure 8, in accordance with various aspects described herein. As used herein, the host 1100 may be or comprise various combinations of hardware and/or software including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1100 may provide one or more services to one or more UEs. [0160] The host 1100 includes processing circuitry 1102 that is operatively coupled via a bus 1104 to an input/output interface 1106, a network interface 1108, a power source 1110, and memory 1112. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 9 and 10, such that the descriptions thereof are generally applicable to the corresponding components of the host 1100.

[0161] The memory 1112 may include one or more computer programs including one or more host application programs 1114 and data 1116, which may include user data, e.g. data generated by a UE for the host 1100 or data generated by the host 1100 for a UE. Embodiments of the host 1100 may utilize only a subset or all of the components shown. The host application programs 1114 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), Moving Picture Experts Group (MPEG), VP9) and audio codecs (e.g., Free Lossless Audio Codec (FLAC), Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, and heads-up display systems). The host application programs 1114 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1100 may select and/or indicate a different host for Over-The-Top (OTT) services for a UE. The host application programs 1114 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (DASH or MPEG-DASH), etc.

[0162] Figure 12 is a block diagram illustrating a virtualization environment 1200 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices, and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more Virtual Machines (VMs) implemented in one or more virtual environments 1200 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

[0163] Applications 1202 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein.

[0164] Hardware 1204 includes processing circuitry, memory that stores software and/or instructions executable by hardware processing circuitry, and/or other hardware devices as described herein, such as a network interface, input/output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1206 (also referred to as hypervisors or VM Monitors (VMMs)), provide VMs 1208A and 1208B (one or more of which may be generally referred to as VMs 1208), and/or perform any of the functions, features, and/or benefits described in relation with some embodiments described herein. The virtualization layer 1206 may present a virtual operating platform that appears like networking hardware to the VMs 1208.

[0165] The VMs 1208 comprise virtual processing, virtual memory, virtual networking, or interface and virtual storage, and may be run by a corresponding virtualization layer 1206. Different embodiments of the instance of a virtual appliance 1202 may be implemented on one or more of the VMs 1208, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as Network Function Virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers and customer premise equipment.

[0166] In the context of NFV, a VM 1208 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non- virtualized machine. Each of the VMs 1208, and that part of the hardware 1204 that executes that VM, be it hardware dedicated to that VM and/or hardware shared by that VM with others of the VMs 1208, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1208 on top of the hardware 1204 and corresponds to the application 1202.

[0167] The hardware 1204 may be implemented in a standalone network node with generic or specific components. The hardware 1204 may implement some functions via virtualization. Alternatively, the hardware 1204 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1210, which, among others, oversees lifecycle management of the applications 1202. In some embodiments, the hardware 1204 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a RAN or a BS. In some embodiments, some signaling can be provided with the use of a control system 1212 which may alternatively be used for communication between hardware nodes and radio units.

[0168] Figure 13 shows a communication diagram of a host 1302 communicating via a network node 1304 with a UE 1306 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as the UE 812A of Figure 8 and/or the UE 900 of Figure 9), the network node (such as the network node 810A of Figure 8 and/or the network node 1000 of Figure 10), and the host (such as the host 816 of Figure 8 and/or the host 1100 of Figure 11) discussed in the preceding paragraphs will now be described with reference to Figure 13.

[0169] Like the host 1100, embodiments of the host 1302 include hardware, such as a communication interface, processing circuitry, and memory. The host 1302 also includes software, which is stored in or is accessible by the host 1302 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 1306 connecting via an OTT connection 1350 extending between the UE 1306 and the host 1302. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 1350.

[0170] The network node 1304 includes hardware enabling it to communicate with the host 1302 and the UE 1306 via a connection 1360. The connection 1360 may be direct or pass through a core network (like the core network 806 of Figure 8) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

[0171] The UE 1306 includes hardware and software, which is stored in or accessible by the UE 1306 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via the UE 1306 with the support of the host 1302. In the host 1302, an executing host application may communicate with the executing client application via the OTT connection 1350 terminating at the UE 1306 and the host 1302. In providing the service to the user, the UE’s client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 1350 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 1350.

[0172] The OTT connection 1350 may extend via the connection 1360 between the host 1302 and the network node 1304 and via a wireless connection 1370 between the network node 1304 and the UE 1306 to provide the connection between the host 1302 and the UE 1306. The connection 1360 and the wireless connection 1370, over which the OTT connection 1350 may be provided, have been drawn abstractly to illustrate the communication between the host 1302 and the UE 1306 via the network node 1304, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0173] As an example of transmitting data via the OTT connection 1350, in step 1308, the host 1302 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1306. In other embodiments, the user data is associated with a UE 1306 that shares data with the host 1302 without explicit human interaction. In step 1310, the host 1302 initiates a transmission carrying the user data towards the UE 1306. The host 1302 may initiate the transmission responsive to a request transmitted by the UE 1306. The request may be caused by human interaction with the UE 1306 or by operation of the client application executing on the UE 1306. The transmission may pass via the network node 1304 in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 1312, the network node 1304 transmits to the UE 1306 the user data that was carried in the transmission that the host 1302 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1314, the UE 1306 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 1306 associated with the host application executed by the host 1302.

[0174] In some examples, the UE 1306 executes a client application which provides user data to the host 1302. The user data may be provided in reaction or response to the data received from the host 1302. Accordingly, in step 1316, the UE 1306 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input/output interface of the UE 1306. Regardless of the specific manner in which the user data was provided, the UE 1306 initiates, in step 1318, transmission of the user data towards the host 1302 via the network node 1304. In step 1320, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 1304 receives user data from the UE 1306 and initiates transmission of the received user data towards the host 1302. In step 1322, the host 1302 receives the user data carried in the transmission initiated by the UE 1306.

[0175] One or more of the various embodiments improve the performance of OTT services provided to the UE 1306 using the OTT connection 1350, in which the wireless connection 1370 forms the last segment.

[0176] In an example scenario, factory status information may be collected and analyzed by the host 1302. As another example, the host 1302 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 1302 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 1302 may store surveillance video uploaded by a UE. As another example, the host 1302 may store or control access to media content such as video, audio, VR, or AR which it can broadcast, multicast, or unicast to UEs. As other examples, the host 1302 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing, and/or transmitting data.

[0177] In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1350 between the host 1302 and the UE 1306 in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1350 may be implemented in software and hardware of the host 1302 and/or the UE 1306. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 1350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or by supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1350 may include message format, retransmission settings, preferred routing, etc.; the reconfiguring need not directly alter the operation of the network node 1304. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency, and the like by the host 1302. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1350 while monitoring propagation times, errors, etc.

[0178] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and/or software needed to perform the tasks, features, functions, and methods disclosed herein. Determining, calculating, obtaining, or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box or nested within multiple boxes, in practice computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and/or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0179] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hardwired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer- readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole and/or by end users and a wireless network generally.

[0180] Some example embodiments of the present disclosure are as follows: [0181] Embodiment 1 : A method performed by a controlling entity (600) for multi -hop sidelink communication, the method comprising:

• configuring (608) a plurality of User Equipments, UEs, to report information about associated wireless links, wherein: o the associated wireless links comprises associated sidelinks and, if any, direct wireless links to a network node; and o the plurality of UEs comprise one or more relay User Equipments, UEs, (602) and a candidate relay UE (604) for candidate end-to-end link from the controlling entity (600) to a remote UE (606), the candidate end-to-end link comprising a candidate multi-hop sidelink to a remote UE (606) via the one or more relay UEs (602) and the candidate relay UE (604);

• receiving (610) the information about the associated wireless links from the plurality of UEs; and

• determining (612) whether the candidate relay UE (604) should transmit a discovery announcement message based on the information about the associated wireless links of the one or more relay UEs (602) and the candidate relay UE (604) for the candidate end- to-end link to the remote UE (606); and

• transmitting (614), directly or indirectly to the candidate relay UE (604), an indication of a result of the determining.

[0182] Embodiment 2: The method of embodiment 1 wherein determining (612) whether the candidate relay UE (604) should transmit a discovery announcement message comprises: computing (612 A) an end-to-end link metric for the candidate end-to-end link to the remote UE (606) based on the information about the associated wireless links of the one or more relay UEs (602) and the candidate relay UE (604) for the candidate end-to-end link to the remote UE (606); and determining (612B) whether the candidate relay UE (604) should transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to-end link. [0183] Embodiment 3: A method performed by a candidate relay User Equipment, UE, (604), the method comprising:

• receiving (608), directly or indirectly from a controlling entity (600), information that configures the candidate relay UE (604) to report information about one or more associated wireless links, wherein the one or more associated wireless links comprises at least one associated sidelinks and, if any, a direct wireless link to a network node;

• transmitting (610), directly or indirectly to the controlling entity (600), the information about the one or more associated wireless links; • receiving (614), directly or indirectly from the controlling entity (600), an indication of whether the candidate relay UE (604) should or is permitted to transit a discovery announcement; and

• operating (616) in accordance with the received indication.

[0184] Embodiment 4: A method performed by a candidate relay User Equipment, UE, (704) for a candidate end-to-end link to a remote UE (706) that comprises a candidate multi-hop sidelink, the method comprising:

• receiving (716) information about wireless links associated to one or more relay UEs (702) and/or one or more other candidate relay UEs in the candidate end-to-end link to the remote UE (706);

• determining (718) whether to transmit a discovery announcement message based on the received information about the wireless links associated to the one or more relay UEs (702) and/or the one or more other candidate relay UEs in the candidate end-to-end link to the remote UE (706); and

• operating (720) in accordance with a result of the determining.

[0185] Embodiment 5: The method of embodiment 4 wherein determining (718) whether to transmit a discovery announcement message comprises:

• computing (718 A) an end-to-end link metric for the candidate end-to-end link to the remote UE (606) based on: o the received information about the wireless links associated to the one or more relay UEs (702) and/or the one or more other candidate relay UEs in the candidate end-to-end link to the remote UE (706); and o information about one or more associated sidelinks of the candidate relay UE (704); and

• determining (718B) whether to transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to-end link.

[0186] Embodiment 6: The method of embodiment 5 further comprising:

• receiving (710), directly or indirectly from a controlling entity (700), information that configures the candidate relay UE (704) with one or more thresholds and/or criteria for determining (718B) whether to transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to-end link;

• wherein determining (718B) whether to transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to-end link comprises determining (718B) whether to transmit a discovery announcement message based on the end-to-end link metric for the candidate end-to-end link and the one or more thresholds and/or criteria.

[0187] Embodiment 7 : The method of embodiment 5 or 6 further comprising receiving (712), directly or indirectly from the controlling entity (700), information that configures the candidate relay UE (704) on the type of end-to-end link metric to be computed, how to compute the end-to-end link metric, or both.

[0188] Embodiment 8: A method performed by a controlling entity (700) for a candidate end-to-end link to a remote UE (706) that comprises a candidate multi-hop sidelink, the method comprising: transmitting (716), directly or indirectly to candidate relay User Equipment, UE, for the candidate multi-hop link, information about wireless links associated to one or more relay UEs (702) and/or one or more other candidate relay UEs in the candidate end-to-end link.

[0189] Embodiment 9: The method of embodiment 8 further comprising transmitting (710), directly or indirectly to the candidate relay UE (704), information that configures the candidate relay UE (704) with one or more thresholds and/or criteria for determining whether to transmit a discovery announcement message based on the information about the wireless links associated to the one or more relay UEs (702) and/or the one or more other candidate relay UEs in the candidate end-to-end link.

[0190] Embodiment 10: The method of embodiment 8 or 9 further comprising transmitting (712), directly or indirectly to the candidate relay UE (704), information that configures the candidate relay UE (704) on a type of end-to-end link metric to be computed for the candidate end-to-end link, how to compute the end-to-end link metric, or both.

[0191] Embodiment 11: A User Equipment, UE, adapted to perform the method of any of embodiments 1 to 7.

[0192] Embodiment 12: A network node adapted to perform the method of any of embodiments 1, 2, or 8 to 10.

[0193] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.