Patent Description:
The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (<NUM>) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (<NUM>) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile wireless devices (WD), as well as communication between network nodes and between WDs <NUM>.

The 3GPP has specified standards for LTE D2D (device-to-device) technology, also known as ProSe (Proximity Services) in 3GPP Technical Release <NUM> and Technical Release <NUM> of LTE. Later in 3GPP Technical Releases <NUM> and <NUM>, LTE vehicle to anything (V2X) related enhancements targeting the specific characteristics of vehicular communications were specified. The 3GPP started a new work item (WI) in August <NUM> within the scope of 3GPP Technical Release <NUM> to develop a new radio (NR) version of V2X communications. The NR V2X standard mainly targets advanced V2X services, which can be categorized into four use case groups: vehicles platooning, extended sensors, advanced driving and remote driving. The advanced V2X services may require an enhanced NR system and a new NR sidelink framework to meet stringent latency and reliability requirements. The NR V2X system also expects to have higher system capacity and better coverage and to allow for an easy extension to support the future development of further advanced V2X services and other services.

Given the targeted services by NR V2X, it is commonly recognized that groupcast/ multicast and unicast transmissions are desired, in which the intended receiver of a message consists of only a subset of the vehicles in proximity to the transmitter (groupcast) or of a single vehicle (unicast). For example, in the platooning service there are certain messages that are only of interest to the members of the platoon, making the members of the platoon a natural groupcast. In another example, the see-through use case most likely involves only a pair of vehicles, for which unicast transmissions naturally fit. Therefore, NR sidelink can support broadcast (as in LTE), groupcast and unicast transmissions. Furthermore, NR sidelink is designed in such a way that its operation is possible with and without network coverage and with varying degrees of interaction between the WDs <NUM> (user equipment) and the NW (network), including support for standalone, network-less operation.

In 3GPP Technical Release <NUM>, place and national security and public safety (NSPS) are considered to be one important use case that can benefit from the already developed NR sidelink features in 3GPP Technical Release <NUM>. Therefore, it is most likely that the 3GPP will specify enhancements related to the NSPS use case taking NR 3GPP Technical Release <NUM> sidelink as a baseline. Besides, in some scenarios, NSPS services need to operate with partial network coverage or without network coverage, such as indoor firefighting, forest firefighting, earthquake rescue, sea rescue, etc., where the infrastructure is partially destroyed or not available. Therefore, coverage extension is an enabler for NSPS, for both NSPS services communicated between WD and cellular network (NW) and communicated between WDs <NUM> over sidelink. In 3GPP Technical Release <NUM>, a new system identification (SID) on NR sidelink relay is used to further explore coverage extension for sidelink-based communication, including both WD to NW relay for cellular coverage extension, and WD to WD relay for sidelink coverage extension.

The Open System Interconnection Model Layer <NUM> (L2) WD to network (NW) relay WD provides the functionality to support connectivity to the <NUM> for remote WDs <NUM>. The protocol stack for L2 WD to NW relay WD is shown in <FIG> for user plane and control plane, respectively. Note that the two endpoints of the packet data convergence protocol (PDCP) link are the remote WD and the network node, e.g., base station (gNB). This means the remote WD has its own context in radio access networks (RAN) and core NW. In other words, the remote WD has its own radio bearer, radio resource control (RRC) connection and packet data unit (PDU) session. The relay function is performed below PDCP, e.g., at the adaptation layer. The remote WD's traffic (both control plane and user plane) is transparently transferred between the remote WD and network node over the L2 WD to NW relay WD without any modifications.

The adaptation layer between the L2 WD to NW relay WD and the network node is able to differentiate between Uu bearers of a particular remote WD. Different remote WDs and different Uu bearers of the remote WD are indicated by additional information (e.g., WD IDs and bearer IDs) included in an adaptation layer header that is added to PDCP PDU. The adaptation layer can be considered as part of PDCP sublayer or a separate new layer between PDCP sublayer and radio link control (RLC) sublayer.

When both the remote WD and the L2 WD to NW relay WD are in RRC idle/inactive mode and there is incoming downlink (DL) traffic for the remote WD, the network node, will first page the remote WD. The L2 WD to NW relay WD monitors the paging and informs the remote WD that there is DL traffic for the remote WD. Then both the remote WD and the L2 WD to NW relay WD establish or resume the RRC connection to the network node and the remote WD's traffic is transparently transferred between the remote WD and network node over the L2 WD to NW relay WD.

The OSI Layer <NUM> (L3) WD to NW relay WD relays unicast traffic (uplink (UL) and downlink (DL)) between the remote WD and the network. The L3 WD to NW relay WD provides generic functions that can relay any Internet protocol (IP), Ethernet or Unstructured traffic. The protocol stack for L3 WD to NW relay WD is shown in <FIG> below where relaying is performed in the PDU layer. The remote WD is invisible to the core NW, i.e., the remote WD does not have its own context and PDU session in the core NW, and its traffic is forwarded in relay WD's PDU session. For Internet Protocol (IP) PDU Session Type and IP traffic over the PC5 reference point, the L3 WD to NW relay WD allocates IPv6 prefix or IPv4 address for the remote WD.

In cases where the L3 WD to NW relay WD is in RRC idle/inactive mode and there is incoming DL traffic for the remote WD, the network node will first page the L3 WD to NW relay WD, which trigger the L3 WD to NW relay WD to establish or resume the RRC connection, and then the NW sends the remote WD's traffic to the L3 WD to NW relay WD which further forwards it to the remote WD.

There are two different resource allocation (RA) procedures for V2X on sidelink, i.e., NW controlled random access (RA) (so called "mode <NUM>" in LTE and "mode <NUM>" in NR) and autonomous RA (so called "mode <NUM>" in LTE and "mode <NUM>" in NR). The transmission resources are selected within a resource pool which is predefined or configured by the network (NW).

With NW controlled random access (RA), the sidelink radio resource for data transmission is scheduled/allocated by the NW. The WD sends a sidelink buffer status report (BSR) to the NW to inform sidelink data available for transmission in the sidelink buffers associated with the MAC entity, and the NW signals the resource allocation to the WD using DCI. With autonomous RA, each device independently decides which radio resources to use for each transmission based at least in part on e.g., sensing.

When performing sensing, the WD decodes the sidelink control information (SCI) transmitted on the physical sidelink control channel (PSCCH) from the surrounding WDs. The WD can know the resources on which the physical sidelink shared channel (PSSCH) is transmitted by these surrounding WDs, and can also know the highest priority of the sidelink LCH(s) in the media access control (MAC) PDU transmitted over PSSCH, which is indicated in the priority field in SCI from the surrounding WDs. The WD also measures a PSSCH reference signal received power (RSRP) and compares it to a threshold. The resource is regarded as unoccupied and available for transmission if the measured PSSCH RSRP of the resource is lower than the threshold. The threshold is set taking the priority of both the sensing WD and the sensed WD(s) into account, in a way that the threshold is set higher if the sensing WD has a higher priority than the sensed WD(s). The resource is more likely regarded unoccupied and available for the sensing WD's transmission.

Sidelink control information (SCI) is carried in the physical sidelink control channel (PSCCH) and is used to enable decoding of the associated data transmission carried in physical sidelink shared channel (PSSCH). The content of the SCI includes the allocated resources, the modulation and coding scheme (MCS), hybrid automatic repeat request (HARQ) related information (e.g., HARQ process ID, new data indicator (NDI), redundancy version (RV), etc.), the intention to reserve the same resources for a future data transmission. Moreover, for sidelink unicast and groupcast, SCI can further include layer-<NUM> destination ID and potentially source ID as well.

A logical channel prioritization (LCP) procedure is applied when a new sidelink transmission is performed. Each sidelink logical channel (LCH) has an associated priority which is prose per packer priority (PPPP) in LTE and, optionally, an associated prose per packet reliability (PPPR). In NR, the associated priority and reliability may be derived from the quality of service (QoS) profile of the sidelink radio bearer.

When the MAC entity allocates resources to sidelink logical channels (LCHs) having data available for transmission, it should first select the Layer2 destination to which the transmission should be performed, based at least in part on the highest priority of all the sidelink LCHs belonging to each L2 destination. Only LCHs with available data are considered, and the L2 destination having the highest priority is selected. After this, sidelink LCHs belonging to the selected L2 destination are served in decreasing order of priority until either the data for the sidelink logical channel(s) or the sidelink grant is exhausted, whichever comes first.

If there are simultaneous UL and sidelink transmissions, prioritization between the UL and sidelink transmission is needed. In LTE, if the UL transmission is not for Msg3 or not prioritized by an upper layer, the sidelink transmission is prioritized if the value of the highest priority of the sidelink LCH(s) in the MAC PDU is lower than thresSL-TxPrioritization (a lower priority value corresponding to a higher priority), where thresSL-TxPrioritization is configured by the NW. In 3GPP NR Technical Release <NUM>, it was considered that the prioritization will consider both UL and sidelink QoS requirements. A separate LCH priority threshold is configured for both UL and SL transmission. The sidelink (SL) transmission is prioritized if the highest priority value of UL LCH(s) with available data is larger than the UL priority threshold and the highest priority value of SL LCH(s) with available data is lower than the SL priority threshold (here a smaller priority value corresponds to a higher priority). Otherwise the UL transmission is prioritized.

If there are simultaneous sidelink transmissions on different frequencies and/or radio access technologies (RATs), and the total sidelink (transmit) Tx power exceeds the maximum allowed Tx power, the WD should decrease the Tx power of the sidelink transmission with the lowest priority, or even drop the transmission. If needed, the procedure is repeated over the non-dropped transmissions, until the maximum allowed Tx power is no longer exceeded.

The logical channel prioritization (LCP) procedure is applied when a new UL transmission is performed, and a starvation avoidance mechanism is introduced to avoid all resources being given to the high priority channel(s)/service(s) so that low priority channel(s)/service(s) have no chance to be served. To implement the starvation avoidance mechanism, a variable Bj is maintained for each LCH j and initially set to zero. Bj is incremented by the product prioritisedBitRate (PBR) × T before every instance of the LCP procedure, where T is the time elapsed since Bj was last incremented If Bj is greater than the bucket size (i.e., PBR × bucketSizeDuration (BSD)), then Bj is set to the bucket size. The exact moment(s) when the WD updates Bj between LCP procedures is up to WD implementation, as long as Bj is up to date at the time when a grant is processed by LCP.

When a new transmission is performed, only LCHs with Bj > <NUM> are allocated resources in a decreasing priority order, and decrement Bj by the total size of MAC SDUs served to LCH j (Bj can be negative after this step). If any resource remains, all the LCHs are served in a strict decreasing priority order (regardless of the value of Bj) until either the data for that logical channel or the UL grant is exhausted, whichever comes first.

With WD to NW relay, the traffic transmitted over PC5 from the remote WD and/or the relay WD may be either traffic terminated at a WD or a relay traffic of the remote WD. The current sidelink (SL) LCP only considers the case that traffic transmitted over PC5 is traffic terminated at a WD, which may not work properly when relay traffic is relayed over PC5.

The scope of the present invention is defined in the appended independent claims. Specific embodiments of the present invention are defined in the dependent claims. Some embodiments advantageously provide methods and WDs for logical channel prioritization with wireless device (WD) to network relay.

According to some aspects, the type of traffic transmitted over the sidelink shared channel (SL-SCH) in sidelink related procedures involving LCP, such as Layer2 (L2) destination selection, intra-WD prioritization between sidelink LCH(s), prioritization between uplink and sidelink transmission, and sensing are provided. Some embodiments may perform at least one of the following:.

Some embodiments disclosed herein are applicable to both L2 WD to NW relay and L3 WD to NW relay arrangements.

According to one aspect, a WD is configured for sidelink communications with another WD. The WD includes processing circuitry configured to: associate a layer <NUM> destination with two priority indices that are initially set to a lowest priority value, a first priority index of the two priority indices indicating a highest priority of a first group of sidelink logical channels carrying sidelink traffic terminated at the WD, a second priority index of the two priority indices indicating a second group of sidelink logical channels which carry relay traffic, the first and second groups of sidelink logical channels including only sidelink logical channels that carry data and that belong to the layer <NUM> destination.

According to this aspect, in some embodiments, upon reception of a grant, a media access control (MAC) entity of the network node selects the layer <NUM> destination based at least in part on the two priority indices. In some embodiments, when the second priority index is lower than a relay priority threshold, the layer <NUM> destination is selected which has a highest priority level of a plurality of layer <NUM> destinations. In some embodiments, when the second priority index is not lower than a relay priority threshold, the layer <NUM> destination is selected which has a first priority index having a highest priority. In some embodiments, upon reception of a grant, after the layer <NUM> destination is selected, a sidelink logical channel is selected belonging to the selected layer <NUM> destination. In some embodiments, the sidelink logical channel is selected by following a decreasing order of logical channel priority. In some embodiments, the sidelink logical channel is selected by following a decreasing order of logical channel priority. In some embodiments, when there are simultaneous uplink and sidelink transmissions, uplink transmissions and sidelink transmissions are prioritized. In some embodiments, the prioritization of the uplink transmissions and the sidelink transmissions is based at least in part on a comparison of the second priority index to a relay priority threshold. In some embodiments, when the WD is configured with sidelink resource allocation mode <NUM>, the WD is configured to perform sensing of uplink traffic and sidelink traffic differently.

According to another aspect, a method in a wireless device (WD) configured for sidelink communications with another WD, includes: associating a layer <NUM> destination with two priority indices that are initially set to a lowest priority value, a first priority index of the two priority indices indicating a highest priority of a first group of sidelink logical channels carrying sidelink traffic terminated at the WD, a second priority index of the two priority indices indicating a second group of sidelink logical channels which carry relay traffic, the first and second groups of sidelink logical channels including only sidelink logical channels that carry data and that belong to the layer <NUM> destination.

According to another aspect, a first wireless device (WD) <NUM> is configured to communicate with at least a second WD <NUM> on sidelink, and to communicate with a network node on an uplink, the first WD <NUM> configured to carry sidelink traffic that terminates at the first WD <NUM> and the second WD <NUM>, and to carry relay traffic between the first WD <NUM> and a network node via the second WD <NUM>. The first WD <NUM> includes processing circuitry configured to: associate each of a plurality of layer <NUM> destinations with a first priority index indicating a first priority level of a first group of sidelink logical channels that carry the sidelink traffic, and a second priority index indicating a second priority level of a second group of sidelink logical channels which carry the relay traffic; and prioritize at least one layer <NUM> destination of the plurality of layer <NUM> destinations based at least in part on at least one of the two priority indices.

According to this aspect, in some embodiments, the first and second groups of sidelink logical channels include only sidelink logical channels that carry data and that belong to a layer <NUM> destination. In some embodiments, the first priority index indicates a sidelink logical channel having a highest priority of all sidelink logical channels which carry the sidelink traffic. In some embodiments, prioritizing the at least one layer <NUM> destination is performed by a media access control, MAC, entity of the first WD <NUM>. In some embodiments, prioritizing the at least one layer <NUM> destination is performed upon reception of a grant from the network node. In some embodiments, a layer <NUM> destination is selected that has a highest second priority level among the layer <NUM> destinations. In some embodiments, when there is no layer <NUM> destination having a second priority level that exceeds a relay priority threshold, then a layer <NUM> destination is selected which has a highest first priority level among the plurality of layer <NUM> destinations. In some embodiments, when there are sidelink logical channels carrying relay traffic and that have a second priority level that exceeds a relay priority threshold, then at least one sidelink logical channel is selected by following a decreasing order of the priority of the logical channel. In some embodiments, when there are sidelink logical channels carrying sidelink traffic and that have a second priority level that exceeds a relay priority threshold, then at least one sidelink logical channel is selected by following a decreasing order of the priority of the logical channel. In some embodiments, when there are sidelink logical channels that have a logical channel priority that does not exceed a sidelink priority threshold and does not exceed a relay priority threshold, then selecting logical channels follows an order of decreasing logical channel priority. In some embodiments, the processing circuitry is further configured to: when uplink transmissions and sidelink transmissions overlap in time, prioritize between uplink transmissions and sidelink transmissions based at least in part on whether the sidelink transmissions carry relay traffic. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, the processing circuitry is further configured to: when there are sidelink logical channels carrying relay traffic and having logical channel priority level that exceeds a relay priority threshold, and when there are also uplink logical channels having logical channel priority level that exceeds an uplink priority threshold and when a highest priority level of the uplink logical channels is higher than a highest priority of all the sidelink logical channels carrying relay traffic: then prioritize the uplink transmissions over the sidelink transmissions; and otherwise, prioritize the sidelink transmissions over the uplink transmissions. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, the processing circuitry is further configured to: when there are sidelink logical channels carrying relay traffic and having logical channel priority level that exceeds a relay priority threshold, and when there are no uplink logical channels having a priority level that exceeds an uplink priority threshold, then: prioritize the sidelink transmissions over the uplink transmissions. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, the processing circuitry is further configured to: when there are no sidelink logical channels carrying relay traffic that also have logical channel priority level that exceeds the relay priority threshold, and when there are uplink logical channels having a priority level that exceeds an uplink priority threshold, then: prioritize the uplink transmissions over the sidelink transmissions. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, the processing circuitry is further configured to: when there are no sidelink logical channels carrying relay traffic that also have logical channel priority level that exceeds a relay priority threshold, and when there are no uplink logical channels having a priority level that exceeds an uplink priority threshold, then: when a highest priority level of all the sidelink logical channels carrying sidelink traffic is higher than a sidelink priority threshold and a highest priority level of the uplink logical channels exceeds a highest priority level of sidelink logical channels carrying relay traffic: then, prioritize the uplink transmissions over the sidelink transmissions; and otherwise, prioritize the sidelink transmissions over the uplink transmissions. In some embodiments, the second priority index further indicates a sidelink logical channel having a highest priority of all sidelink logical channels that carry the relay traffic.

According to yet another aspect, a method is provided in a first wireless device (WD) <NUM> configured to communicate with at least one other WD <NUM> on sidelink, and to communicate with a network node on an uplink, the WD <NUM> configured to carry sidelink traffic that terminates at the first WD <NUM>, and to relay traffic between the first WD <NUM> and a network node. The method includes associating each of a plurality of layer <NUM> destinations with a first priority index indicating a first priority level of a first group of sidelink logical channels that carry the sidelink traffic, and a second priority index indicating a second priority level of a second group of sidelink logical channels which carry the relay traffic; and prioritizing at least one layer <NUM> destination of the plurality of layer <NUM> destinations based at least in part on at least one of the two priority indices.

According to this aspect, in some embodiments, the first and second groups of sidelink logical channels include only sidelink logical channels that carry data and that belong to a layer <NUM> destination. In some embodiments, the first priority index indicates a sidelink logical channel having a highest priority of all sidelink logical channels which carry the sidelink traffic. In some embodiments, prioritizing the at least one layer <NUM> destination is performed by a media access control, MAC, entity of the method. In some embodiments, prioritizing the at least one layer <NUM> destination is performed upon reception of a grant from the network node. In some embodiments, a layer <NUM> destination is selected that has a highest second priority level among the layer <NUM> destinations. In some embodiments, when there is no layer <NUM> destination having a second priority level that exceeds a relay priority threshold, then a layer <NUM> destination is selected which has a highest first priority level among the plurality of layer <NUM> destinations. In some embodiments, when there are sidelink logical channels carrying relay traffic and that have a second priority level that exceeds a relay priority threshold, then at least one sidelink logical channel is selected by following a decreasing order of the priority of the logical channel. In some embodiments, when there are sidelink logical channels carrying sidelink traffic and that have a second priority level that exceeds a relay priority threshold, then at least one sidelink logical channel is selected by following a decreasing order of the priority of the logical channel. In some embodiments, when there are sidelink logical channels that have a logical channel priority that does not exceed a sidelink priority threshold and does not exceed a relay priority threshold, then selecting logical channels follows an order of decreasing logical channel priority. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, prioritizing between uplink transmissions and sidelink transmissions based at least in part on whether the sidelink transmissions carry relay traffic. In some embodiments, the method also includes, when uplink transmissions and sidelink transmissions overlap in time: when there are sidelink logical channels carrying relay traffic and having logical channel priority level that exceeds a relay priority threshold, and when there are also uplink logical channels having logical channel priority level that exceeds an uplink priority threshold and when a highest priority level of the uplink logical channels is higher than a highest priority of all the sidelink logical channels carrying relay traffic: then prioritizing the uplink transmissions over the sidelink transmissions; and otherwise, prioritizing the sidelink transmissions over the uplink transmissions. In some embodiments, the method also includes, when uplink transmissions and sidelink transmissions overlap in time: when there are sidelink logical channels carrying relay traffic and having logical channel priority level that exceeds a relay priority threshold, and when there are no uplink logical channels having a priority level that exceeds an uplink priority threshold, then: prioritizing the sidelink transmissions over the uplink transmissions. In some embodiments, the method also includes, when uplink transmissions and sidelink transmissions overlap in time: when there are no sidelink logical channels carrying relay traffic that also have logical channel priority level that exceeds the relay priority threshold, and when there are uplink logical channels having a priority level that exceeds an uplink priority threshold, then: prioritizing the uplink transmissions over the sidelink transmissions. In some embodiments, the method also includes, when uplink transmissions and sidelink transmissions overlap in time: when there are no sidelink logical channels carrying relay traffic that also have logical channel priority level that exceeds a relay priority threshold, and when there are no uplink logical channels having a priority level that exceeds an uplink priority threshold, then: when a highest priority level of all the sidelink logical channels carrying sidelink traffic is higher than a sidelink priority threshold and a highest priority level of the uplink logical channels exceeds a highest priority level of sidelink logical channels carrying relay traffic: then, prioritizing the uplink transmissions over the sidelink transmissions; and otherwise, prioritizing the sidelink transmissions over the uplink transmissions. In some embodiments, the second priority index further indicates a sidelink logical channel having a highest priority of all sidelink logical channels that carry the relay traffic.

Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to logical channel prioritization with wireless device (WD) to network relay. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

The term "network node" used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term "radio node" used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node.

The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device, etc..

Some embodiments provide logical channel prioritization with wireless device (WD) to network relay. With the methods disclosed herein, the relay traffic relayed over PC5 could be prioritized properly, e.g. avoid that a high priority relay traffic relayed over PC5 is deprioritized if they are regarded as SL traffic terminated at a WD.

Returning now to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in <FIG> a schematic diagram of an example communication system <NUM>, according to an embodiment, such as a 3GPP-type cellular network that may support standards such as LTE and/or NR (<NUM>), which comprises an access network <NUM>, such as a radio access network, and a core network <NUM>. The access network <NUM> comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes <NUM>), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas <NUM>). Each network node 16a, 16b, 16c is connectable to the core network <NUM> over a wired or wireless connection <NUM>. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices <NUM>) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node <NUM>. Note that although only two WDs <NUM> and three network nodes <NUM> are shown for convenience, the communication system may include many more WDs <NUM> and network nodes <NUM>.

A wireless device <NUM> is configured to include an association unit <NUM> which is configured to associate a layer <NUM> destination with two priority indices that are initially set to a lowest priority value.

The host application <NUM> may be operable to provide a service to a remote user, such as a WD <NUM> connecting via an OTT connection <NUM> terminating at the WD <NUM> and the host computer <NUM>. The "user data" may be data and information described herein as implementing the described functionality. In one embodiment, the host computer <NUM> may be configured for providing control and functionality to a service provider and may be operated by the service provider or on behalf of the service provider. The processing circuitry <NUM> of the host computer <NUM> may enable the host computer <NUM> to observe, monitor, control, transmit to and/or receive from the network node <NUM> and or the wireless device <NUM>.

Thus, the network node <NUM> further has software <NUM> stored internally in, for example, memory <NUM>, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node <NUM> via an external connection. The processing circuitry <NUM> may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by network node <NUM>. Processor <NUM> corresponds to one or more processors <NUM> for performing network node <NUM> functions described herein. The memory <NUM> is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software <NUM> may include instructions that, when executed by the processor <NUM> and/or processing circuitry <NUM>, causes the processor <NUM> and/or processing circuitry <NUM> to perform the processes described herein with respect to network node <NUM>.

The processing circuitry <NUM> may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD <NUM>. The processor <NUM> corresponds to one or more processors <NUM> for performing WD <NUM> functions described herein. The WD <NUM> includes memory <NUM> that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software <NUM> and/or the client application <NUM> may include instructions that, when executed by the processor <NUM> and/or processing circuitry <NUM>, causes the processor <NUM> and/or processing circuitry <NUM> to perform the processes described herein with respect to WD <NUM>. For example, the processing circuitry <NUM> of the wireless device <NUM> may include an association unit <NUM> which is configured to associate a layer <NUM> destination with two priority indices that are initially set to a lowest priority value.

In some embodiments, the measurements may be implemented in that the software <NUM>, <NUM> causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection <NUM> while it monitors propagation times, errors, etc..

Although <FIG> and <FIG> show various "units" such as association unit <NUM> as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

<FIG> is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of <FIG> and <FIG>, in accordance with one embodiment. The communication system may include a host computer <NUM>, a network node <NUM> and a WD <NUM>, which may be those described with reference to <FIG>. In a first step of the method, the host computer <NUM> provides user data (Block S100). In an optional substep of the first step, the host computer <NUM> provides the user data by executing a host application, such as, for example, the host application <NUM> (Block S102). In a second step, the host computer <NUM> initiates a transmission carrying the user data to the WD <NUM> (Block S104). In an optional third step, the network node <NUM> transmits to the WD <NUM> the user data which was carried in the transmission that the host computer <NUM> initiated, in accordance with the teachings of the embodiments described throughout this disclosure (Block S106). In an optional fourth step, the WD <NUM> executes a client application, such as, for example, the client application <NUM>, associated with the host application <NUM> executed by the host computer <NUM> (Block S108).

<FIG> is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of <FIG>, in accordance with one embodiment. The communication system may include a host computer <NUM>, a network node <NUM> and a WD <NUM>, which may be those described with reference to <FIG> and <FIG>. In a first step of the method, the host computer <NUM> provides user data (Block S110). In an optional substep (not shown) the host computer <NUM> provides the user data by executing a host application, such as, for example, the host application <NUM>. In a second step, the host computer <NUM> initiates a transmission carrying the user data to the WD <NUM> (Block S112). In an optional third step, the WD <NUM> receives the user data carried in the transmission (Block S114).

<FIG> is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of <FIG>, in accordance with one embodiment. The communication system may include a host computer <NUM>, a network node <NUM> and a WD <NUM>, which may be those described with reference to <FIG> and <FIG>. In an optional first step of the method, the WD <NUM> receives input data provided by the host computer <NUM> (Block S116). In an optional substep of the first step, the WD <NUM> executes the client application <NUM>, which provides the user data in reaction to the received input data provided by the host computer <NUM> (Block S118). Additionally or alternatively, in an optional second step, the WD <NUM> provides user data (Block S120). In an optional substep of the second step, the WD provides the user data by executing a client application, such as, for example, client application <NUM> (Block S122). In providing the user data, the executed client application <NUM> may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the WD <NUM> may initiate, in an optional third substep, transmission of the user data to the host computer <NUM> (Block S124). In a fourth step of the method, the host computer <NUM> receives the user data transmitted from the WD <NUM>, in accordance with the teachings of the embodiments described throughout this disclosure (Block S126).

<FIG> is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of <FIG>, in accordance with one embodiment. The communication system may include a host computer <NUM>, a network node <NUM> and a WD <NUM>, which may be those described with reference to <FIG> and <FIG>. In an optional first step of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the network node <NUM> receives user data from the WD <NUM> (Block S128). In an optional second step, the network node <NUM> initiates transmission of the received user data to the host computer <NUM> (Block S130). In a third step, the host computer <NUM> receives the user data carried in the transmission initiated by the network node <NUM> (Block S132).

<FIG> is a flowchart of an example process in a wireless device <NUM> according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of wireless device <NUM> such as by one or more of processing circuitry <NUM> (including the association unit <NUM>), processor <NUM>, radio interface <NUM> and/or communication interface <NUM>. Wireless device <NUM> such as via processing circuitry <NUM> and/or processor <NUM> and/or radio interface <NUM> is configured to associate a layer <NUM> destination with two priority indices that are initially set to a lowest priority value, a first priority index of the two priority indices indicating a highest priority of a first group of sidelink logical channels carrying sidelink traffic terminated at the WD, a second priority index of the two priority indices indicating a second group of sidelink logical channels which carry relay traffic, the first and second groups of sidelink logical channels including only sidelink logical channels that carry data and that belong to the layer <NUM> destination (Block S134).

<FIG> is a flowchart of another example process in a WD <NUM> according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of wireless device <NUM> such as by one or more of processing circuitry <NUM> (including the association unit <NUM>), processor <NUM>, radio interface <NUM> and/or communication interface <NUM>. Wireless device <NUM> such as via processing circuitry <NUM> and/or processor <NUM> and/or radio interface <NUM> is configured to associate each of a plurality of layer <NUM> destinations with a first priority index indicating a first priority level of a first group of sidelink logical channels that carry the sidelink traffic, and a second priority index indicating a second priority level of a second group of sidelink logical channels which carry the relay traffic (Block S136). The process also includes prioritizing at least one layer <NUM> destination of the plurality of layer <NUM> destinations based at least in part on at least one of the two priority indices (Block S138).

Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for logical channel prioritization with wireless device (WD) to network (NW) relay.

Some embodiments are described in the context of NR sidelink communications. However, it is understood that embodiments are in general applicable to any kind of direct communications between WDs <NUM> involving device-to-device (D2D) communications. In the description below, a relay WD <NUM> may refer to a WD to NW relay WD <NUM>. Further, although embodiments may refer to using a relay WD <NUM>, the disclosure and implementations are not limited to such. Rather, it is understood that a general concept of the disclosure considers a first interface, e.g., sidelink interface, which may carry traffic to/from a second interface, e.g., Uu, and may do so without specifically employing a WD to NW relay WD <NUM>.

In some embodiments, the SL from a remote WD <NUM> to a relay WD <NUM> and, from a relay WD <NUM> to a remote WD <NUM> are considered. In some embodiments, each LCH or destination is associated with at least a priority index. A low priority value means high priority level, while a high priority value means low priority level. The term "relay traffic" is used to denote traffic transmitted between a remote WD <NUM> and a network node <NUM> in a relay scenario. In addition, the term "SL local traffic" is used to stand for traffic transmitted between a remote WD <NUM> and a relay WD <NUM> in a relay scenario. In the embodiments discussed below, a WD <NUM> may be a remote WD <NUM> or a relay WD <NUM> unless specified.

In a first embodiment, a L2 destination is associated with two priority indices which are initially set to the lowest priority value. The first priority index is determined as the highest priority of all the sidelink LCHs which carry SL traffic terminated at a WD <NUM>, and the second priority index is determined as the highest priority of all the sidelink LCHs which carry relay traffic (i.e., the traffic is transmitted between a remote WD <NUM> and a network node <NUM>), where only LCHs with available data and belonging to the L2 destination are considered.

In some embodiments, upon reception of a grant (i.e., with SL resource allocation Mode <NUM> or Mode <NUM>), the MAC entity selects the L2 destination to which the transmission should be performed considering both the first priority index and the second priority index. More specifically:.

In some embodiments, upon reception of a grant (i.e., with SL resource allocation Mode <NUM> or Mode <NUM>), after a L2 destination has been selected, the WD <NUM> further selects sidelink LCHs (with data available) belonging to the selected L2 destination in the following way.

The procedure may stop until either the data for the sidelink LCH(s) or the sidelink grant is exhausted, whichever comes first.

In some embodiments, for a WD <NUM>, if there are simultaneous UL and sidelink transmission overlapping in time, prioritization between UL and sidelink transmission is performed by the WD <NUM> taking into account whether or not the sidelink carries relay traffic. More specifically and for example:.

If there are no sidelink LCH(s) carrying relay traffic, then UL/SL prioritization may be performed.

In some embodiments, for a WD <NUM> with SL resource allocation Mode <NUM>, the WD <NUM> performs sensing for relay traffic and SL traffic differently according to their respective priority index. In an example, in case the WD <NUM> has both SL LCHs carrying relay traffic and SL LCHs carrying SL traffic, the priority value indicated in SCI could be set to the smaller value between the priority value of highest priority of all the sidelink LCH(s) carrying relay traffic and the priority value of highest priority of all the sidelink LCH(s) carrying SL traffic. Optionally, a delta value may be added to the priority value carried in the SCI. The delta value could be predefined or configured by the NW using dedicated or common signaling. It should be set to a negative value, which means the priority used in sensing may be increased when there is relay traffic carried, so that the resource is more likely regarded as unoccupied and available for the WD's transmission.

According to one aspect, a WD <NUM> is configured for sidelink communications with another WD <NUM>. The WD <NUM> includes processing circuitry <NUM> configured to: associate a layer <NUM> destination with two priority indices that are initially set to a lowest priority value, a first priority index of the two priority indices indicating a highest priority of a first group of sidelink logical channels carrying sidelink traffic terminated at the WD <NUM>, a second priority index of the two priority indices indicating a second group of sidelink logical channels which carry relay traffic, the first and second groups of sidelink logical channels including only sidelink logical channels that carry data and that belong to the layer <NUM> destination.

According to this aspect, in some embodiments, upon reception of a grant, a media access control (MAC) entity of the WD <NUM> selects the layer <NUM> destination based at least in part on the two priority indices. In some embodiments, when the second priority index is lower than a relay priority threshold, the layer <NUM> destination is selected which has a highest priority level of a plurality of layer <NUM> destinations. In some embodiments, when the second priority index is not lower than a relay priority threshold, the layer <NUM> destination is selected which has a first priority index having a highest priority. In some embodiments, upon reception of a grant, after the layer <NUM> destination is selected, a sidelink logical channel is selected belonging to the selected layer <NUM> destination. In some embodiments, the sidelink logical channel is selected by following a decreasing order of logical channel priority. In some embodiments, the sidelink logical channel is selected by following a decreasing order of logical channel priority. In some embodiments, when there are simultaneous uplink and sidelink transmissions, uplink transmissions and sidelink transmissions are prioritized. In some embodiments, the prioritization of the uplink transmissions and the sidelink transmissions is based at least in part on a comparison of the second priority index to a relay priority threshold. In some embodiments, when the WD <NUM> is configured with sidelink resource allocation mode <NUM>, the WD <NUM> is configured to perform sensing of uplink traffic and sidelink traffic differently.

According to another aspect, a method in a wireless device (WD) <NUM> configured for sidelink communications with another WD <NUM>, includes: associating a layer <NUM> destination with two priority indices that are initially set to a lowest priority value, a first priority index of the two priority indices indicating a highest priority of a first group of sidelink logical channels carrying sidelink traffic terminated at the WD <NUM>, a second priority index of the two priority indices indicating a second group of sidelink logical channels which carry relay traffic, the first and second groups of sidelink logical channels including only sidelink logical channels that carry data and that belong to the layer <NUM> destination.

According to this aspect, in some embodiments, upon reception of a grant, a media access control (MAC) entity of the WD selects the layer <NUM> destination based at least in part on the two priority indices. In some embodiments, when the second priority index is lower than a relay priority threshold, the layer <NUM> destination is selected which has a highest priority level of a plurality of layer <NUM> destinations. In some embodiments, when the second priority index is not lower than a relay priority threshold, the layer <NUM> destination is selected which has a first priority index having a highest priority. In some embodiments, upon reception of a grant, after the layer <NUM> destination is selected, a sidelink logical channel is selected belonging to the selected layer <NUM> destination. In some embodiments, the sidelink logical channel is selected by following a decreasing order of logical channel priority. In some embodiments, the sidelink logical channel is selected by following a decreasing order of logical channel priority. In some embodiments, when there are simultaneous uplink and sidelink transmissions, uplink transmissions and sidelink transmissions are prioritized. In some embodiments, the prioritization of the uplink transmissions and the sidelink transmissions is based at least in part on a comparison of the second priority index to a relay priority threshold. In some embodiments, when the WD <NUM> is configured with sidelink resource allocation mode <NUM>, the WD <NUM> is configured to perform sensing of uplink traffic and sidelink traffic differently.

According to another aspect, a first wireless device (WD) <NUM> is configured to communicate with at least a second WD <NUM> on sidelink, and to communicate with a network node <NUM> on an uplink, the first WD <NUM> configured to carry sidelink traffic that terminates at the first WD <NUM> and the second WD <NUM>, and to carry relay traffic between the first WD <NUM> and a network node <NUM> via the second WD <NUM>. The first WD <NUM> includes processing circuitry <NUM> configured to: associate each of a plurality of layer <NUM> destinations with a first priority index indicating a first priority level of a first group of sidelink logical channels that carry the sidelink traffic, and a second priority index indicating a second priority level of a second group of sidelink logical channels which carry the relay traffic; and prioritize at least one layer <NUM> destination of the plurality of layer <NUM> destinations based at least in part on at least one of the two priority indices.

According to this aspect, in some embodiments, the first and second groups of sidelink logical channels include only sidelink logical channels that carry data and that belong to a layer <NUM> destination. In some embodiments, the first priority index indicates a sidelink logical channel having a highest priority of all sidelink logical channels which carry the sidelink traffic. In some embodiments, prioritizing the at least one layer <NUM> destination is performed by a media access control, MAC, entity of the first WD <NUM>. In some embodiments, prioritizing the at least one layer <NUM> destination is performed upon reception of a grant from the network node <NUM>. In some embodiments, a layer <NUM> destination is selected that has a highest second priority level among the layer <NUM> destinations. In some embodiments, when there is no layer <NUM> destination having a second priority level that exceeds a relay priority threshold, then a layer <NUM> destination is selected which has a highest first priority level among the plurality of layer <NUM> destinations. In some embodiments, when there are sidelink logical channels carrying relay traffic and that have a second priority level that exceeds a relay priority threshold, then at least one sidelink logical channel is selected by following a decreasing order of the priority of the logical channel. In some embodiments, when there are sidelink logical channels carrying sidelink traffic and that have a second priority level that exceeds a relay priority threshold, then at least one sidelink logical channel is selected by following a decreasing order of the priority of the logical channel. In some embodiments, when there are sidelink logical channels that have a logical channel priority that does not exceed a sidelink priority threshold and does not exceed a relay priority threshold, then selecting logical channels follows an order of decreasing logical channel priority. In some embodiments, the processing circuitry <NUM> is further configured to: when uplink transmissions and sidelink transmissions overlap in time, prioritize between uplink transmissions and sidelink transmissions based at least in part on whether the sidelink transmissions carry relay traffic. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, the processing circuitry <NUM> is further configured to: when there are sidelink logical channels carrying relay traffic and having logical channel priority level that exceeds a relay priority threshold, and when there are also uplink logical channels having logical channel priority level that exceeds an uplink priority threshold and when a highest priority level of the uplink logical channels is higher than a highest priority of all the sidelink logical channels carrying relay traffic: then prioritize the uplink transmissions over the sidelink transmissions; and otherwise, prioritize the sidelink transmissions over the uplink transmissions. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, the processing circuitry <NUM> is further configured to: when there are sidelink logical channels carrying relay traffic and having logical channel priority level that exceeds a relay priority threshold, and when there are no uplink logical channels having a priority level that exceeds an uplink priority threshold, then: prioritize the sidelink transmissions over the uplink transmissions. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, the processing circuitry <NUM> is further configured to: when there are no sidelink logical channels carrying relay traffic that also have logical channel priority level that exceeds the relay priority threshold, and when there are uplink logical channels having a priority level that exceeds an uplink priority threshold, then: prioritize the uplink transmissions over the sidelink transmissions. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, the processing circuitry <NUM> is further configured to: when there are no sidelink logical channels carrying relay traffic that also have logical channel priority level that exceeds a relay priority threshold, and when there are no uplink logical channels having a priority level that exceeds an uplink priority threshold, then: when a highest priority level of all the sidelink logical channels carrying sidelink traffic is higher than a sidelink priority threshold and a highest priority level of the uplink logical channels exceeds a highest priority level of sidelink logical channels carrying relay traffic: then, prioritize the uplink transmissions over the sidelink transmissions; and otherwise, prioritize the sidelink transmissions over the uplink transmissions. In some embodiments, the second priority index further indicates a sidelink logical channel having a highest priority of all sidelink logical channels that carry the relay traffic.

According to yet another aspect, a method is provided in a first wireless device, WD, (<NUM>) configured to communicate with at least one other WD <NUM> on sidelink, and to communicate with a network node <NUM> on an uplink, the WD <NUM> configured to carry sidelink traffic that terminates at the first WD <NUM>, and to relay traffic between the first WD <NUM> and a network node <NUM>. The method includes associating each of a plurality of layer <NUM> destinations with a first priority index indicating a first priority level of a first group of sidelink logical channels that carry the sidelink traffic, and a second priority index indicating a second priority level of a second group of sidelink logical channels which carry the relay traffic; and prioritizing at least one layer <NUM> destination of the plurality of layer <NUM> destinations based at least in part on at least one of the two priority indices.

According to this aspect, in some embodiments, the first and second groups of sidelink logical channels include only sidelink logical channels that carry data and that belong to a layer <NUM> destination. In some embodiments, the first priority index indicates a sidelink logical channel having a highest priority of all sidelink logical channels which carry the sidelink traffic. In some embodiments, prioritizing the at least one layer <NUM> destination is performed by a media access control, MAC, entity of the method. In some embodiments, prioritizing the at least one layer <NUM> destination is performed upon reception of a grant from the network node <NUM>. In some embodiments, a layer <NUM> destination is selected that has a highest second priority level among the layer <NUM> destinations. In some embodiments, when there is no layer <NUM> destination having a second priority level that exceeds a relay priority threshold, then a layer <NUM> destination is selected which has a highest first priority level among the plurality of layer <NUM> destinations. In some embodiments, when there are sidelink logical channels carrying relay traffic and that have a second priority level that exceeds a relay priority threshold, then at least one sidelink logical channel is selected by following a decreasing order of the priority of the logical channel. In some embodiments, when there are sidelink logical channels carrying sidelink traffic and that have a second priority level that exceeds a relay priority threshold, then at least one sidelink logical channel is selected by following a decreasing order of the priority of the logical channel. In some embodiments, when there are sidelink logical channels that have a logical channel priority that does not exceed a sidelink priority threshold and does not exceed a relay priority threshold, then selecting logical channels follows an order of decreasing logical channel priority. In some embodiments, when uplink transmissions and sidelink transmissions overlap in time, prioritizing between uplink transmissions and sidelink transmissions based at least in part on whether the sidelink transmissions carry relay traffic. In some embodiments, the method also includes, when uplink transmissions and sidelink transmissions overlap in time: when there are sidelink logical channels carrying relay traffic and having logical channel priority level that exceeds a relay priority threshold, and when there are also uplink logical channels having logical channel priority level that exceeds an uplink priority threshold and when a highest priority level of the uplink logical channels is higher than a highest priority of all the sidelink logical channels carrying relay traffic: then prioritizing the uplink transmissions over the sidelink transmissions; and otherwise, prioritizing the sidelink transmissions over the uplink transmissions. In some embodiments, the method also includes, when uplink transmissions and sidelink transmissions overlap in time: when there are sidelink logical channels carrying relay traffic and having logical channel priority level that exceeds a relay priority threshold, and when there are no uplink logical channels having a priority level that exceeds an uplink priority threshold, then: prioritizing the sidelink transmissions over the uplink transmissions. In some embodiments, the method also includes, when uplink transmissions and sidelink transmissions overlap in time: when there are no sidelink logical channels carrying relay traffic that also have logical channel priority level that exceeds the relay priority threshold, and when there are uplink logical channels having a priority level that exceeds an uplink priority threshold, then: prioritizing the uplink transmissions over the sidelink transmissions. In some embodiments, the method also includes, when uplink transmissions and sidelink transmissions overlap in time: when there are no sidelink logical channels carrying relay traffic that also have logical channel priority level that exceeds a relay priority threshold, and when there are no uplink logical channels having a priority level that exceeds an uplink priority threshold, then: when a highest priority level of all the sidelink logical channels carrying sidelink traffic is higher than a sidelink priority threshold and a highest priority level of the uplink logical channels exceeds a highest priority level of sidelink logical channels carrying relay traffic: then, prioritizing the uplink transmissions over the sidelink transmissions; and otherwise, prioritizing the sidelink transmissions over the uplink transmissions. In some embodiments, the second priority index further indicates a sidelink logical channel having a highest priority of all sidelink logical channels that carry the relay traffic.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++.

Accordingly, all embodiments can be combined in any way and/or combination, all falling within the scope of the appended claims.

Claim 1:
A method in a first wireless device, WD, (<NUM>) configured to communicate with at least one other WD (<NUM>) on sidelink, and to communicate with a network node on an uplink, the WD (<NUM>) configured to carry sidelink traffic that terminates at the first WD (<NUM>), and to relay traffic between the first WD (<NUM>) and a network node (<NUM>), the method comprising:
associating (S136) each of a plurality of layer <NUM> destinations with a first priority index indicating a first priority level of a first group of sidelink logical channels that carry the sidelink traffic, and a second priority index indicating a second priority level of a second group of sidelink logical channels which carry the relay traffic;
prioritizing (S138) at least one layer <NUM> destination of the plurality of layer <NUM> destinations based at least in part on at least one of the two priority indices; and
when uplink transmissions and sidelink transmissions overlap in time, prioritizing between uplink transmissions and sidelink transmissions based at least in part on whether the sidelink transmissions carry relay traffic.