CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of US provisional application No. 63/257757 entitled “SL DATA TRANSMISSION CONSIDERING SL DRX ACTIVE TIME” filed 20 October 2021, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The example and non-limiting embodiments relate generally to sidelink communication and, more particularly, to sidelink transmission resource allocation.

BACKGROUND

[0003] It is known, in sidelink communication, to determine the active time for multiple UEs.

SUMMARY

[0004] The following summary is merely intended to be illustrative. The summary is not intended to limit the scope of the claims.

[0005] In accordance with one aspect, an apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: determine prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and select at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0006] In accordance with one aspect, a method comprising: determining, with a transmitting user equipment, prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and selecting at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0007] In accordance with one aspect, an apparatus comprising means for performing: determining prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and selecting at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0008] In accordance with one aspect, a non-transitory computer-readable medium comprising program instructions stored thereon which, when executed with at least one processor, cause the at least one processor to: determine prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and select at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The foregoing aspects and other features are explained in the following description, taken in connection with the accompanying drawings, wherein:

[0010] FIG. 1 is a block diagram of one possible and non-limiting example system in which the example embodiments may be practiced;

[0011] FIG. 2 is a diagram illustrating features as described herein;

[0012] FIG. 3 is a diagram illustrating features as described herein; and

[0013] FIG. 4 is a flowchart illustrating steps as described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0014] The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows: 3 GPP third generation partnership project

5G fifth generation

5GC 5G core network

AMF access and mobility management function

CU central unit

D2D device-to-device

DRX discontinuous reception

DU distributed unit eNB (or eNodeB) evolved Node B (e.g., an LTE base station)

EN-DC E-UTRA-NR dual connectivity en-gNB or En-gNB node providing NR user plane and control plane protocol terminations towards the UE, and acting as secondary node in EN- DC

E-UTRA evolved universal terrestrial radio access, i.e., the LTE radio access technology gNB (or gNodeB) base station for 5G/NR, i.e., a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC

HARQ hybrid automatic repeat request

I/F interface

KPI key performance indicator

LI layer 1

LCH logical channel

LCP logical channel prioritization

LTE long term evolution

MAC medium access control

ML maximum likelihood

MME mobility management entity

NACK negative acknowledgement ng or NG new generation ng-eNB or NG-eNB new generation eNB NR new radio

N/W or NW network

PDB packet delay budget

PDCP packet data convergence protocol

PHY physical layer

ProSe proximity service

QoS quality of service

RAN radio access network

RF radio frequency

RLC radio link control

RRC radio resource control

RRH remote radio head

RS reference signal

RSRP reference signal received power

RU radio unit

Rx receiver

SCI sidelink control information

SDAP service data adaptation protocol

SDU service data unit

SGW serving gateway

SIB system information block

SL sidelink

SL-DRX sidelink discontinuous reception

SMF session management function sPBR sidelink prioritized bit rate

Tx transmitter

UE user equipment (e.g., a wireless, typically mobile device)

UPF user plane function

V2X vehicle-to-everything [0015] Turning to FIG. 1, this figure shows a block diagram of one possible and nonlimiting example in which the examples may be practiced. A user equipment (UE) 110, radio access network (RAN) node 170, and network element(s) 190 are illustrated. In the example of FIG. 1, the user equipment (UE) 110 is in wireless communication with a wireless network 100. A UE is a wireless device that can access the wireless network 100. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a module 140, comprising one of or both parts 140-1 and/or 140-2, which may be implemented in a number of ways. The module 140 may be implemented in hardware as module 140-1, such as being implemented as part of the one or more processors 120. The module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user equipment 110 to perform one or more of the operations as described herein. The UE 110 communicates with RAN node 170 via a wireless link 111.

[0016] Although not illustrated in FIG. 1, the UE 110 may also communicate with other UEs via short range communication technologies, such as, IEEE 802. l ip, Bluetooth® etc. If wireless communication with a network is unavailable or not possible, or in addition to network communication, the UE 110 may be capable of sidelink communication with other UEs.

[0017] The RAN node 170 in this example is a base station that provides access by wireless devices such as the UE 110 to the wireless network 100. The RAN node 170 may be, for example, a base station for 5G, also called New Radio (NR). In 5G, the RAN node 170 may be a NG-RAN node, which is defined as either a gNB or a ng-eNB. A gNB is a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to a 5GC (such as, for example, the network element(s) 190). The ng-eNB is a node providing E-UTRA user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC. The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and distributed unit(s) (DUs) (gNB-DUs), of which DU 195 is shown. Note that the DU may include or be coupled to and control a radio unit (RU). The gNB-CU is a logical node hosting RRC, SDAP and PDCP protocols of the gNB or RRC and PDCP protocols of the en-gNB that controls the operation of one or more gNB-DUs. The gNB-CU terminates the Fl interface connected with the gNB-DU. The Fl interface is illustrated as reference 198, although reference 198 also illustrates a link between remote elements of the RAN node 170 and centralized elements of the RAN node 170, such as between the gNB-CU 196 and the gNB-DU 195. The gNB-DU is a logical node hosting RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is partly controlled by gNB-CU. One gNB-CU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface 198 connected with the gNB-CU. Note that the DU 195 is considered to include the transceiver 160, e.g., as part of a RU, but some examples of this may have the transceiver 160 as part of a separate RU, e.g., under control of and connected to the DU 195. The RAN node 170 may also be an eNB (evolved NodeB) base station, for LTE (long term evolution), or any other suitable base station or node.

[0018] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/W I/F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include the processor(s) 152, memories 155, and network interfaces 161. Note that the DU 195 may also contain its own memory/memories and processor(s), and/or other hardware, but these are not shown. [0019] The RAN node 170 includes a module 150, comprising one of or both parts 150-1 and/or 150-2, which may be implemented in a number of ways. The module 150 may be implemented in hardware as module 150-1, such as being implemented as part of the one or more processors 152. The module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 150 may be implemented as module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, cause the RAN node 170 to perform one or more of the operations as described herein. Note that the functionality of the module 150 may be distributed, such as being distributed between the DU 195 and the CU 196, or be implemented solely in the DU 195.

[0020] The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. Two or more gNBs 170 may communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards.

[0021] The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for gNB implementation for 5G, with the other elements of the RAN node 170 possibly being physically in a different location from the RRH/DU, and the one or more buses 157 could be implemented in part as, for example, fiber optic cable or other suitable network connection to connect the other elements (e.g., a central unit (CU), gNB-CU) of the RAN node 170 to the RRH/DU 195. Reference 198 also indicates those suitable network link(s).

[0022] It is noted that description herein indicates that “cells” perform functions, but it should be clear that equipment which forms the cell will perform the functions. The cell makes up part of a base station. That is, there can be multiple cells per base station. For example, there could be three cells for a single carrier frequency and associated bandwidth, each cell covering one-third of a 360 degree area so that the single base station’s coverage area covers an approximate oval or circle. Furthermore, each cell can correspond to a single carrier and a base station may use multiple carriers. So if there are three 120 degree cells per carrier and two carriers, then the base station has a total of 6 cells.

[0023] The wireless network 100 may include a network element or elements 190 that may include core network functionality, and which provides connectivity via a link or links 181 with a further network, such as a telephone network and/or a data communications network (e.g., the Internet). Such core network functionality for 5G may include access and mobility management function(s) (AMF(s)) and/or user plane functions (UPF(s)) and/or session management function(s) (SMF(s)). Such core network functionality for LTE may include MME (Mobility Management Entity )/SGW (Serving Gateway) functionality. These are merely illustrative functions that may be supported by the network element(s) 190, and note that both 5G and LTE functions might be supported. The RAN node 170 is coupled via a link 131 to a network element 190. The link 131 may be implemented as, e.g., an NG interface for 5G, or an SI interface for LTE, or other suitable interface for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N/W I/F(s)) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause the network element 190 to perform one or more operations.

[0024] The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented, at some level, using hardware such as processors 152 or 175 and memories 155 and 171, and also such virtualized entities create technical effects. [0025] The computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer readable memories 125, 155, and 171 may be means for performing storage functions. The processors 120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples. The processors 120, 152, and 175 may be means for performing functions, such as controlling the UE 110, RAN node 170, and other functions as described herein.

[0026] In general, the various embodiments of the user equipment 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, tablets with wireless communication capabilities, as well as portable units or terminals that incorporate combinations of such functions. In addition, various embodiments of the user equipment 110 can include, but are not limited to, devices integrated into vehicles, infrastructure associated with vehicular travel, wearable devices used by pedestrians or other non-vehicular users of roads, user equipment unrelated to traffic users, and user equipment configured to participate in sidelink scenarios, such as public safety user equipment and/or other commercial user equipment.

[0027] Features as described herein generally relate to, while not being limited to, new radio (NR) sidelink (SL). For example, NR SL methods may be implemented to provide communication between a vehicle and a network, infrastructure(s), other vehicle(s), or other road user(s) in the surrounding/immediate area. Such communication may enable proximity service (ProSe), or transmission of information about the surrounding environment, between devices in close proximity, for example device-to-device (D2D) communication technology. Such direct communication may be available even when network coverage is unavailable. Additionally or alternatively, NR SL methods may be implemented in scenarios unrelated to traffic users, such as public safety scenarios and/or commercial scenarios. Enhancements to sidelink procedures may be applicable in these vehicle-to-everything (V2X) and other use cases. It should be noted that enhancements to sidelink procedures may not be limited to unicast procedures; a person of ordinary skill in the art would understand that the present disclosure may relate to sidelink groupcast, multicast, and/or broadcast procedures as well.

[0028] Features as described herein generally relate to sidelink discontinuous transmission and reception. In sidelink enhancement work item 3GPP RAN2#115, it was agreed that: “When data is available for transmission to one or more RX UE in DRX, TX UE selects the resources taking into account the active time (current or future) of the RX UE(s) determined by the timers maintained at the TX UE.” In previous meetings, it has been agreed that the Tx UE maintains timers for the connected Rx UEs; Tx UE knowledge about active time has been implemented. However, there has not yet been any agreements or discussion on the topic of how Tx UE resource selection based on Rx UE active time(s) should be done. Example embodiments of the present disclosure may take into account the active time for multiple Rx UEs connected to the same Tx UE in sidelink operation.

[0029] Tdoc R2-2107654, from Fujitsu, notes the following:

“...Option 1 : The destination is selected only among the destinations having the corresponding SL DRX active time including the time duration of the SL grants during the sidelink LCP procedure. As a result, the TX UE would select a destination having the corresponding SL DRX active time including the time duration of the SL grants.

Option 2: Configure higher priority to the logical channels with the destination’s corresponding SL DRX active time including the time duration of the SL grants. In this option, when selecting a destination having the logical channel with the highest priority, the TX UE has higher probability to select the destination having the corresponding SL DRX active time including the time duration of the SL grant...”

[0030] MAC already specifies that the logical channels selected for the SL grant are sorted based on the priority in section 5.22.1.4.1.3 of TS38.321. The above proposals both suggest ensuring selection of the data for which the SL grant fits with the SL active time. However, to optimize the resource selection by the Tx UE in SL, it may be beneficial to, in addition, not immediately select any data if it has the potential to still fulfil the latency bound, even if sent in a later grant. Example embodiments of the present disclosure may relate to consideration of the latency bound (or other QoS related metrics/KPIs) during resource selection.

[0031] In an example embodiment, which may cover an implementation of the agreement above, high priority SL data may be allowed to be delayed, if the latency bound (e.g. total or remaining PDB) allows for the data to be transmitted in a later grant. This may allow SL data of lower priority, but with more strict latency bounds (i.e. because such data has previously been deprioritized due to the relatively low priority and hence delayed), to be transmitted within the bounds. In other words, the sorting/selection of previously not sent, or low priority SL data, may be selected for later transmission due to the SL-DRX constraints.

[0032] In an example embodiment, for sidelink data to be transmitted, a MAC entity may allocate resources to the destination with the highest priority logical channel for SL, in decreasing priority, according to 5.22.1.4.1.3 and/or based on one or more conditions. For example, resources may be allocated to a logical channel if sidelink active time is available for that logical channel. For example, resources may be allocated to a logical channel if the sidelink grant is included in the sidelink active time for the logical channel. For example, resources may be allocated to a logical channel if the latency bound for the data in the logical channel fits within (i.e. would not exceed) the latency bound for the data indicated by the sidelink active time, or if the sidelink active time of the receiving UE is not available in/to the transmitting UE. For example, resources may be allocated to a logical channel if the latency bound for the data of the logical channel does not fit within an expected upcoming sidelink grant. One or more of these conditions may be combined during resource allocation to the logical channels for SL.

[0033] It may be noted that a destination may have multiple logical channels associated with. A destination may comprise a single UE (i.e. unicast) or multiple UEs (i.e. groupcast or broadcast). A destination may be selected based on the highest associated priority channel. For example, if there are two logical channels, each with a different destination and a different active time, it may be that the selected logical channel will have a different destination than what would be selected than if, simply, the highest priority logical channel was selected.

[0034] When a Tx UE has multiple connected Rx UEs, they may have different starting and ending time of their (respective) active time due to different configurations. Referring now to FIG. 2, illustrated is a non-limiting example of inconsistencies with SL DRX configurations. When a Tx UE (UE-A 200) has multiple connected Rx UEs (UE-B 210 and UE-C 220), it may be that either of these has different starting and ending time of their active time due to different configuration. In other words, the active time of a Tx UE may be at least partially misaligned or not aligned with the active time of an Rx UE. In the illustrated example, UE-A (200) may be configured with active time between time T2 (240) and time T3 (250). However, UE-B (210) may actually be active between times T2 (240) and T4 (250), while UE-C (220) may actually be active between times T1 (230) and T3 (250). It may be noted that, due to different SL-DRX configurations, the Tx UE may have more flexibility than its own provided SL-DRX configuration intended, thus allowing transmission in a larger time window.

[0035] As the configuration of the DRX parameters is Tx-centric, even though the UE- A (200) may have attempted to configure a similar active time for UE-B (210) and UE-C (220), it may be that a second, or third Tx UE (not illustrated) has configured different DRX parameters for either or both of these Rx UEs (UE-B 210, UE-C 220). This may result in a scenario such as illustrated in FIG. 2, where either UE-B (210) or UE-C (220) stops, or even starts the active time before the other, and partly irrespectively of the Tx UE’s configuration (200), although the (amount of) active time may still be compliant with the UE-A’s provided SL DRX configuration (200).

[0036] In an example embodiment, a Tx UE (e.g. 200) may take into account that the UE-C’s active time (220) starts already at T1 (230) in FIG. 2, which may provide a more flexible boundary for the latency bound to be met. This may mean that the Tx UE (200) may not only account for its own configuration of the SL active time, but also for the Rx UE(s)’s reported SL active time.

[0037] In another example embodiment, the UE-A (200) may take into account the reliability requirement of the SL data to one of the UEs; in other words, the UE-A (200) may select resources in such a way as to ensure sufficient time for potential re-transmissions. This may imply that the resource selection process follows the following conditions:

> If the requirement (i.e. QoS) for a given lower priority logical channel(s) indicates that the data may have numerous retransmissions, and

> the size of the data of the logical channel(s) with higher priority data may still fit within the sidelink grant,

> allocate the lower priority logical channel(s) to the sidelink grant

[0038] Such definition may allow for even further flexibility, as it may ensure that logical channels with high reliability requirement are transmitted early enough in the active time period of the Rx UE, as to allow for more potential retransmissions (either blind or requested by HARQ) to be processed within the active time.

[0039] In an example embodiment, a reprioritization mechanism (in the MAC) for the mapping of logical channels associated with a given LCP (priority) to available SL grants may be introduced. The reprioritization mechanism may take into account the receiver UE’s different SL-DRX configurations i.e. active time.

[0040] In an example embodiment, a destination may be selected with consideration of 1) not only criterion such as: the destination may be selected from only among the destinations having the corresponding SL DRX active time, including the time duration of the SL grants during the sidelink logical channel prioritization (LCP) procedure; 2) but also whether the latency bound for the logical channels fits within a coming start of the sidelink active time and the expected number of retransmissions. In an example embodiment, data which can be sent in the next DRX cycle may be deprioritized, and lower priority data may be transmitted with a larger expected number of retransmissions before that deprioritized data is transmitted.

[0041] In an example embodiment, mapping logical channels to available SL grants may comprise reordering the LCP (e.g. prioritization value) by taking SL-DRX (e.g. active time) into account.

[0042] In an example embodiment, Tx UE destination selection may be based on whether, i.e. the latency bound for the logical channels is not exceeded, even when transmitting data for the higher priority logical channel in a known/expected coming SL grant, with transmission time within the sidelink active time for the destination/logical channel, which may allow deprioritizing data which may be sent in the next DRX cycle.

[0043] In an example embodiment, the reliability requirement (i.e. allowed/expected number of retransmissions for the given dataset) may be included/utilized in the reprioritization mechanism. As an example, if the data is expected to have many retransmissions (i.e. due to bad channel conditions, a threshold distance between Tx/Rx pair, etc.), the logical channel may be used for destination selection, even though it has a lower priority than other data.

[0044] In an example embodiment, sorting of logical channels to be used for the selection of a destination may be based on end-points of the sidelink active time (e.g. in FIG. 2, for UE-B 210, T2 (240) and T4 (260)). This may result in prioritizing transmitting the ones with the shortest time till the Rx UE goes inactive.

[0045] In an example embodiment, new SL grants in the upcoming active time (i.e. next transmission opportunity) may be considered by the reprioritization mechanism based on the TX UE’s knowledge of the applied SL-DRX pattern of the RX UE, when the packet delay budget (PDB) allows for that. [0046] In an example embodiment, when sidelink relay adapts the SL DRX procedure, it may also be relevant to consider the remaining PDB of a given transmission towards one or more UEs.

[0047] Referring now to FIG. 3, illustrated are examples of resource selection scenarios considering logical channel (LCH) priority as well as QoS requirements and/or link quality. In an example embodiment, the UE-A (300, 320) may be allowed to calculate/use the probability of a HARQ NACK based on defined criteria such as, for example, distance, RSRP, history/ML metrics, or others, to determine the assumed/expected required number of retransmissions, and hence the urgency of placing the logical channel with high reliability requirement early in the Rx UE’s active time. In a first example, the UE-A (300) may transmit LCH 1 (340) and LCH 2 (350) in a first grant, LCH 2 (350) and LCH 3 (360) in a second grant, and LCH 3 (360) in a third grant to UE-B (Rx UE 310). The sorted priority of the logical channels (LCH) may be LCH 1 > LCH 2 > LCH 3 (340, 350, 360, respectively), but the (assumed) amount of retransmissions of LCH 3 (360) may be 3 higher than LCH 2 (350), which may be higher than that of LCH 1 (340). Assuming there are multiple sidelink grants available to UE-A (300) in UE-B’s active time (310), a mechanism for resource selection may quickly converge towards the first example, where LCH 1 (340) is selected first, along with LCH 2 (350), but as LCH 2 (350) has a required retransmission, and will be scheduled in the second grant, along with LCH 3 (360), which is yet again retransmitted in the third grant within the active time. However, assuming for example that LCH 3 (360) has poor radio conditions/high QoS requirements, it may be more beneficial to perform resource selection according to the second example (UE-A 320, UE-B 330).

[0048] In a second example, based on this priority information, LCH 3 (360) may be transmitted by UE-A (Tx UE 320) in the first grant with LCH 2 (350), as LCH 1 (340) may be assumed to have good radio conditions/low quality of service (QoS) requirement. This may allow for LCH 3 (360) to be (re)transmitted 3 times, whereas LCH 2 (350) and LCH 1 (340) may still be able to be transmitted successfully. In the illustrated example, LCH 2 (350) and LCH 3 (360) may be transmitted in a second grant, and LCH 2 (350) and LCH 1 (340) may be transmitted in a third grant to UE-B (Rx UE 330). [0049] In an example embodiment, resource selection by a Tx UE may be performed based on a threshold for the LCH 1 to be de-prioritized, according to the following: for all logical channels of which the priority is above a (pre)configured threshold; assign the logical channels to the sidelink grant according to legacy (including previous suggested methods) for all remaining logical channels;

Calculate assumed number of (re)transmissions based on one or more (example) metrics; radio link quality; or previous history for HARQ feedback for the logical channel; or

QoS requirements; sort the logical channels based on the above assign the logical channels to the sidelink grant

[0050] In an example embodiment, if a given set of data on a logical channel has been unsuccessfully transmitted for a number of consecutive times, the likelihood that the logical channel is selected before other higher priority channels may be increased. Additionally or alternatively, if multiple previous sets of data has needed multiple transmissions per set, the likelihood that the logical channel is selected before other higher priority channels may be increased.

[0051] A technical effect of example embodiments of the present disclosure may be to allow lower priority logical channels to be used for destination selection, as they may fit better within DRX (i.e. active time and latency bounds) than higher priority logical channels.

[0052] In an example embodiment, the Tx UE may consider the DRX of a potential remote/relay UE, as to reduce latency of the entire data transfer. For example, for a multi- hop relay case, the UE may prioritize data with many hops, as to reduce the overall latency. If the connected remote/second-relay UE has shorter/longer inactive time, the UE may be (de)prioritized, as it may be more difficult to reach said UE.

[0053] In an example embodiment, the network may further configure a Tx UE, through dedicated RRC signaling, system information block (SIB), or pre-configuration, as to how to prioritize sidelink transmissions over Uu data transfer. In legacy (Rel-16) procedures, the Uu and SL transmission is prioritized based on two thresholds. However, when including SL DRX in the prioritization equation, this type of prioritization may not be optimal, as it may result in decreased power saving efficiency. For example, the receiving UE may need to stay active for a longer period of time in order to receive the data and/or potential missed receive opportunities over sidelink due to being unable to send retransmissions during inactive time.

[0054] FIG. 4 illustrates the potential steps of an example method 400. The example method 400 may include: determining prioritization for respective ones of one or more resources for transmission to a receiving user equipment, 410; and selecting at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization, 420. The example method 400 may be performed, for example, with a transmitting user equipment.

[0055] In accordance with one example embodiment, an apparatus may comprise: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: determine prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and select at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0056] The at least one selected resource may be allocated to one or more sidelink logical channels. [0057] The example apparatus may be further configured to: determine an active time of the receiving user equipment, wherein determining the prioritization may comprise determining the prioritization based, at least partially, on the determined active time.

[0058] The at least one selected resource may be further configured for transmission of sidelink control information.

[0059] Selecting the at least one resource of the one or more resources may comprise the example apparatus being further configured to: determine that one or more first resources of the one or more resources have a priority below a threshold; determine a number of at least one of: expected transmissions, or expected retransmissions for respective ones of the one or more first resources based, at least partially, on at least one of: radio link quality, a hybrid automatic repeat request feedback history for data transmission on the respective ones of the one or more first resources, a reliability requirement for data transmission on the respective ones of the one or more first resources; or one or more quality of service requirements for data transmission on the respective ones of the one or more first resources; re-sort the one or more first resources based, at least partially, on the determined number; and select the at least one resource based, at least partially, on the one or more re-sorted first resources.

[0060] The example apparatus may be further configured to: prioritize sidelink transmissions over Uu data transfer based, at least partially, on the one or more re-sorted first resources in response to at least one of: a configuration received through dedicated radio resource control signaling, a system information block, or a pre-configuration.

[0061] Selecting the at least one resource may comprise selecting the at least one resource further based on a latency bound associated with the at least one resource.

[0062] Selecting the at least one resource may comprise selecting the at least one resource further based on at least one of: a determination that the latency bound associated with the at least one resource fits within a latency bound associated with an active time of the receiving user equipment, a determination that the latency bound associated with the at least one resource fits within a latency bound associated with a sleep time of the receiving user equipment, a determination that the active time of the receiving user equipment is not available, or a determination that the latency bound associated with the at least one resource does not fit within a latency bound associated with an upcoming sidelink grant.

[0063] Selecting the at least one resource may comprise selecting the at least one resource further based on a latency bound associated with one or more other, high priority resources of the one or more resources.

[0064] An active time of the apparatus may be at least partially misaligned with an active time of the receiving user equipment.

[0065] Selecting the at least one resource may comprise selecting the at least one resource further based on a comparison of a size of the data with a size of the sidelink grant.

[0066] The example apparatus may be further configured to: deprioritize at least a first resource of the one or more resources based on a determination that the first resource is capable of being transmitted to the receiving user equipment in a next discontinuous reception cycle.

[0067] Determining the prioritization may comprise determining the prioritization based, at least partially, on a number of relay hops associated with the respective ones of the one or more resources, or an inactive time associated with a destination of the respective ones of the one or more resources.

[0068] In accordance with one aspect, an example method may be provided comprising: determining, with a transmitting user equipment, prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and selecting at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0069] The at least one selected resource may be allocated to one or more sidelink logical channels. [0070] The example method may further comprise: determining an active time of the receiving user equipment, wherein determining the prioritization may comprise determining the prioritization based, at least partially, on the determined active time.

[0071] The at least one selected resource may be further configured for transmission of sidelink control information.

[0072] The selecting of the at least one resource of the one or more resources may comprise: determining that one or more first resources of the one or more resources have a priority below a threshold; determining a number of at least one of: expected transmissions, or expected retransmissions for respective ones of the one or more first resources based, at least partially, on at least one of: radio link quality, a hybrid automatic repeat request feedback history for data transmission on the respective ones of the one or more first resources, a reliability requirement for data transmission on the respective ones of the one or more first resources; or one or more quality of service requirements for data transmission on the respective ones of the one or more first resources; re-sorting the one or more first resources based, at least partially, on the determined number; and selecting the at least one resource based, at least partially, on the one or more re-sorted first resources.

[0073] The example method may further comprise: prioritizing sidelink transmissions over Uu data transfer based, at least partially, on the one or more re-sorted first resources in response to at least one of: a configuration received through dedicated radio resource control signaling, a system information block, or a pre-configuration.

[0074] The selecting of the at least one resource may comprise selecting the at least one resource further based on a latency bound associated with the at least one resource.

[0075] The selecting of the at least one resource may comprise selecting the at least one resource further based on at least one of: a determination that the latency bound associated with the at least one resource fits within a latency bound associated with an active time of the receiving user equipment, a determination that the latency bound associated with the at least one resource fits within a latency bound associated with a sleep time of the receiving user equipment, a determination that the active time of the receiving user equipment is not available, or a determination that the latency bound associated with the at least one resource does not fit within a latency bound associated with an upcoming sidelink grant.

[0076] The selecting of the at least one resource may comprise selecting the at least one resource further based on a latency bound associated with one or more other, high priority resources of the one or more resources.

[0077] An active time of the transmitting user equipment may be at least partially misaligned with an active time of the receiving user equipment.

[0078] The selecting of the at least one resource may comprise selecting the at least one resource further based on a comparison of a size of the data with a size of the sidelink grant.

[0079] The example method may further comprise: deprioritizing at least a first resource of the one or more resources based on a determination that the first resource is capable of being transmitted to the receiving user equipment in a next discontinuous reception cycle.

[0080] The determining of the prioritization may comprise determining the prioritization based, at least partially, on a number of relay hops associated with the respective ones of the one or more resources, or an inactive time associated with a destination of the respective ones of the one or more resources.

[0081] In accordance with one example embodiment, an apparatus may comprise: circuitry configured to perform: determine prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and select at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0082] In accordance with one example embodiment, an apparatus may comprise: processing circuitry; memory circuitry including computer program code, the memory circuitry and the computer program code configured to, with the processing circuitry, enable the apparatus to: determine prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and select at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0083] As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.” This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0084] In accordance with one example embodiment, an apparatus may comprise means for performing: determining prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and selecting at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0085] The at least one selected resource may be allocated to one or more sidelink logical channels. [0086] The means may be further configured to perform: determining an active time of the receiving user equipment, wherein determining the prioritization may comprise determining the prioritization based, at least partially, on the determined active time.

[0087] The at least one selected resource may be further configured for transmission of sidelink control information.

[0088] The means configured to perform selecting of the at least one resource of the one or more resources may comprise means configured to perform: determining that one or more first resources of the one or more resources have a priority below a threshold; determining a number of at least one of: expected transmissions, or expected retransmissions for respective ones of the one or more first resources based, at least partially, on at least one of: radio link quality, a hybrid automatic repeat request feedback history for data transmission on the respective ones of the one or more first resources, a reliability requirement for data transmission on the respective ones of the one or more first resources; or one or more quality of service requirements for data transmission on the respective ones of the one or more first resources; re-sorting the one or more first resources based, at least partially, on the determined number; and selecting the at least one resource based, at least partially, on the one or more re-sorted first resources.

[0089] The means may be further configured to perform: prioritizing sidelink transmissions over Uu data transfer based, at least partially, on the one or more re-sorted first resources in response to at least one of: a configuration received through dedicated radio resource control signaling, a system information block, or a pre-configuration.

[0090] The means configured to perform selecting of the at least one resource may comprise means configured to perform selecting the at least one resource further based on a latency bound associated with the at least one resource.

[0091] The means configured to perform selecting of the at least one resource may comprise means configured to perform selecting the at least one resource further based on at least one of: a determination that the latency bound associated with the at least one resource fits within a latency bound associated with an active time of the receiving user equipment, a determination that the latency bound associated with the at least one resource fits within a latency bound associated with a sleep time of the receiving user equipment, a determination that the active time of the receiving user equipment is not available, or a determination that the latency bound associated with the at least one resource does not fit within a latency bound associated with an upcoming sidelink grant.

[0092] The means configured to perform selecting of the at least one resource may comprise means configured to perform selecting the at least one resource further based on a latency bound associated with one or more other, high priority resources of the one or more resources.

[0093] An active time of the apparatus may be at least partially misaligned with an active time of the receiving user equipment.

[0094] The means configured to perform selecting of the at least one resource may comprise means configured to perform selecting the at least one resource further based on a comparison of a size of the data with a size of the sidelink grant.

[0095] The means may be further configured to perform: deprioritizing at least a first resource of the one or more resources based on a determination that the first resource is capable of being transmitted to the receiving user equipment in a next discontinuous reception cycle.

[0096] The means configured to perform determining of the prioritization may comprise means configured to perform determining the prioritization based, at least partially, on a number of relay hops associated with the respective ones of the one or more resources, or an inactive time associated with a destination of the respective ones of the one or more resources.

[0097] In accordance with one example embodiment, a non-transitory computer- readable medium comprising program instructions stored thereon which, when executed with at least one processor, cause the at least one processor to: determine prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and select at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[0098] The at least one selected resource may be allocated to one or more sidelink logical channels.

[0099] The example non-transitory computer-readable medium may be further configured to: determine an active time of the receiving user equipment, wherein determining the prioritization may comprise determining the prioritization based, at least partially, on the determined active time.

[00100] The at least one selected resource may be further configured for transmission of sidelink control information.

[00101] Selecting the at least one resource of the one or more resources may comprise the example non-transitory computer-readable medium being further configured to: determine that one or more first resources of the one or more resources have a priority below a threshold; determine a number of at least one of: expected transmissions, or expected retransmissions for respective ones of the one or more first resources based, at least partially, on at least one of: radio link quality, a hybrid automatic repeat request feedback history for data transmission on the respective ones of the one or more first resources, a reliability requirement for data transmission on the respective ones of the one or more first resources; or one or more quality of service requirements for data transmission on the respective ones of the one or more first resources; re-sort the one or more first resources based, at least partially, on the determined number; and select the at least one resource based, at least partially, on the one or more re-sorted first resources.

[00102] The example non-transitory computer-readable medium may be further configured to: prioritize sidelink transmissions over Uu data transfer based, at least partially, on the one or more re-sorted first resources in response to at least one of: a configuration received through dedicated radio resource control signaling, a system information block, or a pre-configuration. [00103] Selecting the at least one resource may comprise selecting the at least one resource further based on a latency bound associated with the at least one resource.

[00104] Selecting the at least one resource may comprise selecting the at least one resource further based on at least one of: a determination that the latency bound associated with the at least one resource fits within a latency bound associated with an active time of the receiving user equipment, a determination that the latency bound associated with the at least one resource fits within a latency bound associated with a sleep time of the receiving user equipment, a determination that the active time of the receiving user equipment is not available, or a determination that the latency bound associated with the at least one resource does not fit within a latency bound associated with an upcoming sidelink grant.

[00105] Selecting the at least one resource may comprise selecting the at least one resource further based on a latency bound associated with one or more other, high priority resources of the one or more resources.

[00106] An active time of a transmitting user equipment may be at least partially misaligned with an active time of the receiving user equipment.

[00107] Selecting the at least one resource may comprise selecting the at least one resource further based on a comparison of a size of the data with a size of the sidelink grant.

[00108] The example non-transitory computer-readable medium may be further configured to: deprioritize at least a first resource of the one or more resources based on a determination that the first resource is capable of being transmitted to the receiving user equipment in a next discontinuous reception cycle.

[00109] Determining the prioritization may comprise determining the prioritization based, at least partially, on a number of relay hops associated with the respective ones of the one or more resources, or an inactive time associated with a destination of the respective ones of the one or more resources.

[00110] In accordance with another example embodiment, a non-transitory program storage device readable by a machine may be provided, tangibly embodying a program of instructions executable by the machine for performing operations, the operations comprising: determine prioritization for respective ones of one or more resources for transmission to a receiving user equipment; and select at least one resource of the one or more resources for transmission of data, with a sidelink grant, to the receiving user equipment based, at least partially, on the determined prioritization.

[00111] It should be understood that the foregoing description is only illustrative. Various alternatives and modifications can be devised by those skilled in the art. For example, features recited in the various dependent claims could be combined with each other in any suitable combination(s). In addition, features from different embodiments described above could be selectively combined into a new embodiment. Accordingly, the description is intended to embrace all such alternatives, modification and variances which fall within the scope of the appended claims.