Method for operating a user equipment, user equipment, radio communication system, and computer-readable medium

Abstract

A user equipment UE for a wireless communication network is described. The wireless communication network includes a plurality of user equipment UEs. The UE communicates with one or more other user equipment UEs of the wireless communication network via a direct link. In response to a trigger for transmission, the UE performs a sensing process for determining resources to be used for transmission. The sensing process includes a plurality of radio resource selection processes. The UE selects a radio resource selection process to be applied from the plurality of radio resource selection processes according to one or more of the following: traffic density, traffic density of different types of traffic, user density within a predefined area around the UE.

Description

Technical Field

[0001] This application relates to the field of wireless communication systems or networks, and more particularly, to communication between user equipments (UEs) of a wireless communication network using a direct link (SL). Background Art

[0002] FIG. 1 is a schematic representation of an example of a terrestrial wireless network 100, which, as shown in FIG. 1(a), includes a core network 102 and one or more radio access networks RAN1, RAN2, … RAN N . FIG. 1(b) is a schematic representation of an example of a radio access network RAN n that may include one or more base stations gNB1 to gNB5. Each base station serves a specific area around the base station schematically represented by corresponding cells 1061 to 1065. The base stations are provided to serve users within the cells. One or more base stations may serve users in authorized and / or unauthorized frequency bands. The term base station (BS) refers to a gNB in a 5G network, an eNB in UMTS / LTE / LTE-A / LTE-A Pro, or simply a BS in other mobile communication standards. A user may be a fixed device or a mobile device. The wireless communication system may also be accessed through mobile or fixed IoT devices connected to the base stations or users. The mobile device or the fixed device may include a physical device, a ground vehicle such as a robot or a car, an aircraft, such as a manned or unmanned aerial vehicle (UAV), also known as a drone, a building, and other articles or devices that have electronic devices, software, sensors, actuators, etc. embedded therein, and a network connection enabling these devices to collect and exchange data on an existing network infrastructure. FIG. 1(b) shows an exemplary view of five cells. However, RANn may include more or fewer such cells, and RAN nIt may also include only one base station. Fig. 1(b) shows two users UE1 and UE2 located in cell 1062 and served by base station gNB2, also referred to as user equipment or user device. Another user UE3 is shown in cell 1064 served by base station gNB4. Arrows 1081, 1082, and 1083 schematically represent the uplink / downlink connections for transmitting data from users UE1, UE2, and UE3 to base stations gNB2, gNB4 or for transmitting data from base stations gNB2, gNB4 to users UE1, UE2, UE3. This can be achieved in licensed or unlicensed frequency bands. In addition, Fig. 1(b) shows two additional devices 1101 and 1102 in cell 1064, such as IoT devices, which can be fixed or mobile devices. Device 1101 accesses the wireless communication system via base station gNB4 to receive and send data, as schematically represented by arrow 1121. Device 1102 accesses the wireless communication system via user UE3, as schematically represented by arrow 1122. Each base station gNB1 to gNB5 can be connected to the core network 102, for example via the S1 interface, via the respective backhaul links 1141 to 1145, which are schematically represented by arrows pointing to "core" in Fig. 1(b). The core network 102 can be connected to one or more external networks. The external network can be the Internet or a private network, such as an intranet or any other type of campus network, for example a private WiFi communication system or a 4G or 5G mobile communication system. In addition, some or all of the base stations gNB1 to gNB5 can be interconnected via their respective backhaul links 1161 to 1165, for example via the S1 or X2 interface or the XN interface in NR, which is schematically represented by arrows pointing to "gNBs" in Fig. 1(b). The direct link channel allows direct communication between UEs, also known as device-to-device D2D communication. The direct link interface in 3GPP is named PC5.

[0003] For data transmission, a physical resource grid can be used. The physical resource grid may include a set of resource elements to which various physical channels and physical signals are mapped. For example, the physical channels may include physical downlink, uplink, and sidelink shared channels PDSCH, PUSCH, PSSCH that carry user-specific data (also referred to as downlink, uplink, and sidelink payload data), a physical broadcast channel PBCH that carries, for example, a master information block MIB and one or more system information blocks SIB, one or more sidelink information blocks SLIB (if supported), physical downlink, uplink, and sidelink control channels PDCCH, PUCCH, PSSCH that carry, for example, downlink control information DCI, uplink control information UCI, and sidelink control information SCI, and a physical sidelink feedback channel PSFCH that carries PC5 feedback responses. The sidelink interface may support two levels of SCI, which refers to a first control region (also referred to as level 1 SCI) that contains certain parts of the SCI, and an optional second control region (also referred to as level 2 SCI) that contains a second part of the control information.

[0004] For the uplink, the physical channel may further include a physical random access channel PRACH or RACH, which is used by the UE to access the network when the UE is synchronized and has obtained the MIB and SIB. The physical signals may include reference signals or symbols (RS), synchronization signals, etc. The resource grid may include a frame or radio frame that has a certain duration in the time domain and a given bandwidth in the frequency domain. The frame may have a certain number of subframes of a predefined length (e.g., 1 ms). Each subframe may include one or more time slots of 12 or 14 OFDM symbols, depending on the cyclic prefix CP length. The frame may also have a smaller number of OFDM symbols, for example, when using a shortened transmission time interval sTTI or a mini-slot / non-slot frame structure that includes only a small number of OFDM symbols.

[0005] The wireless communication system may be any single-tone or multi-carrier system that uses frequency division multiplexing, such as an orthogonal frequency division multiplexing (OFDM) system, an orthogonal frequency division multiple access (OFDMA) system, or any other inverse fast Fourier transform (IFFT)-based signal with or without a cyclic prefix (CP), such as DFT-s-OFDM. Other waveforms may be used, such as non-orthogonal waveforms for multiple access, such as filter bank multi-carrier (FBMC), generalized frequency division multiplexing (GFDM), or universal filtered multi-carrier (UFMC). The wireless communication system may operate, for example, according to the LTE-Advanced pro standard or the 5G or NR (New Radio) standard, or the NR-U (New Radio-Unlicensed) standard.

[0006] The wireless network or communication system depicted in FIG. 1 can be a heterogeneous network with different overlapping networks, such as a macrocell network, where each macrocell includes macro base stations such as base stations gNB1 to gNB5, and a network of small cell base stations such as femtocell base stations or picocell base stations (not shown in FIG. 1). In addition to the above-mentioned terrestrial wireless networks, there also exists a non-terrestrial wireless communication network NTN, including spaceborne transceivers such as satellites and / or airborne transceivers such as unmanned aerial vehicle systems. The non-terrestrial wireless communication network or system can operate in a similar manner to the terrestrial system described above with reference to FIG. 1, for example, according to the LTE-Advanced Pro standard or the 5G or NR (New Radio) standard.

[0007] In a mobile communication network, such as the network described above with reference to FIG. 1, such as an LTE or 5G / NR network, there can be UEs that communicate directly with each other through one or more direct link SL channels, for example, using the PC5 / PC3 interface or WiFi Direct for communication. UEs that communicate directly with each other through a direct link can include vehicles that communicate directly with other vehicles (V2V communication), vehicles that communicate with other entities of the wireless communication network (V2X communication), and other entities such as roadside units RSU, roadside entities such as traffic lights, traffic signs, or pedestrians. The RSU can have the functions of a BS or a UE, depending on the specific network configuration. Other UEs may not be vehicle-related UEs and can include any of the above-mentioned devices. Such devices can also communicate directly with each other using the SL channel, i.e., D2D communication. When considering two UEs communicating directly through a direct link, for example, using the PC5 / PC3 interface, one of the UEs can also be connected to the BS, and information can be relayed from the BS to the other UE via the direct link interface, and vice versa. The relay can be performed within the same frequency band (in-band relay) or can use another frequency band (out-of-band relay). In the first case, communication on the Uu and direct link can be decoupled using different time slots, as in a time-division duplex (TDD) system.

[0008] Figure 2It is a schematic diagram of an in-coverage scenario, where two UEs communicating directly with each other are both connected to a base station. The coverage area of the base station gNB is schematically represented by a circle 200, which basically corresponds to the cell schematically shown in FIG. 1. The UEs communicating directly with each other include a first vehicle 202 and a second vehicle 204 located within the coverage area 200 of the base station gNB. Both of these vehicles 202, 204 are connected to the base station gNB, and in addition, they are directly connected to each other via the PC5 interface. The gNB assists in the scheduling and / or interference management of V2V traffic through control signaling on the Uu interface (i.e., the radio interface between the base station and the UE). That is, the gNB provides SL resource allocation configuration or assistance for the UEs, and the gNB allocates resources to be used for V2V communication through the direct link. This configuration is also called mode 1 configuration in NR V2X and mode 3 configuration in LTE V2X.

[0009] Figure 3 It is a schematic diagram of an out-of-coverage scenario, where the UEs communicating directly with each other either are not connected to the base station, although they may be physically located within the cell of the wireless communication network, or some or all of the UEs communicating directly with each other are connected to the base station, but the base station does not provide SL resource allocation configuration or assistance. Three vehicles 206, 208, and 210 are shown in the figure communicating directly with each other through a direct link, for example, using the PC5 interface. The scheduling and / or interference management of V2V traffic is based on an algorithm implemented between the vehicles. This configuration is also called mode 2 configuration in NR V2X and mode 4 configuration in LTE V2X. As described above, Figure 3 The scenario of an out-of-coverage scenario in does not necessarily mean that the mode 2 UEs in the corresponding NR or mode 4 UEs in LTE are outside the coverage 200 of the base station, but means that the mode 2 UEs in the corresponding NR or mode 4 UEs in LTE are not served by the base station, are not connected to the base station in the coverage area, or are connected to the base station but do not receive the SL resource allocation configuration or assistance from the base station. Therefore, there may be a situation where, Figure 2 within the coverage area 200 shown in, in addition to the NR mode 1 or LTE mode 3 UEs 202, 204, there are also NR mode 2 or LTE mode 4 UEs 206, 208, 210. In addition, Figure 3 An out-of-coverage UE communicating with the network using a relay is schematically shown. For example, UE 210 can communicate with UE 212 through a direct link, and UE 212 can be connected to the gNB via the Uu interface. Therefore, UE 212 can relay information between the gNB and UE 210.

[0010] Although Figure 2 and Figure 3A vehicle UE is shown, but it should be noted that the described in-coverage and out-of-coverage scenarios also apply to non-vehicle UEs. In other words, any UE that uses the SL channel to communicate directly with another UE, such as a handheld device, can be in-coverage and out-of-coverage.

[0011] It should be noted that the information in the above section is only for enhancing the understanding of the background of the present invention. Therefore, it may contain information that does not constitute the prior art known to those of ordinary skill in the art.

[0012] Based on the above, it may be necessary to improve or enhance the communication of user equipment via a direct link. Summary of the Invention

[0013] The present invention provides a user equipment UE for a wireless communication network, the wireless communication network including a plurality of user equipment UEs, wherein the UE is configured to communicate with one or more other user equipment UEs of the wireless communication network via a direct link, wherein, in response to a trigger for transmission, the UE performs a sensing process for determining resources for transmission, the sensing process including a plurality of radio resource selection processes, and wherein the UE is configured to select a radio resource selection process to be applied from the plurality of radio resource selection processes based on one or more of: traffic density, traffic density of different types of traffic, user density within a predefined area around the UE. Brief Description of the Drawings

[0014] Embodiments of the present invention will now be described in further detail with reference to the accompanying drawings:

[0015] FIG. 1 is a schematic representation of an example of a terrestrial wireless network, where FIG. 1(a) shows a core network and one or more radio access networks, and FIG. 1(b) is a schematic representation of an example of a radio access network RAN;

[0016] Figure 2 is a schematic representation of an in-coverage scenario, where two UEs communicating directly with each other are both connected to a base station;

[0017] Figure 3 is a schematic representation of an out-of-coverage scenario, where UEs communicate directly with each other;

[0018] Figure 4 shows a sensing process performed by a UE autonomously selecting resources for transmission;

[0019] Figure 5 shows an example of continuous partial sensing in an energy-saving V-UE;

[0020] Figure 6 is a schematic representation of a wireless communication system including a transmitter such as a base station for implementing an embodiment of the present invention, and one or more receivers such as user equipment UEs;

[0021] Figure 7 shows a block diagram of a traffic density-based resource selection mechanism according to an embodiment of the present invention; and

[0022] Figure 8 shows an example of a computer system on which units or modules and method steps described according to the method of the present invention can be executed.

[0023] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, in which the same or similar elements are designated with the same reference numerals. Detailed Description of the Invention

[0024] In a wireless communication system or network, as described above with reference to FIG. 1 or Figure 2 or Figure 3 the wireless communication system described, a user equipment UE may communicate via a direct link SL. For example, in an out-of-coverage scenario as described with reference to Figure 4 According to 3GPP Release 16 for NR direct links, a UE, such as a vehicle UE, V-UE, must continuously perform sensing to identify unoccupied radio resources in the time domain and frequency domain for an arriving transport block TB (i.e., the TB arriving at the V-UE, e.g., from an application or service executed by the V-UE and to be sent via the SL) such that relevant delay budgets and reliability requirements are met. However, an increasing number of user equipments using direct link communication are UEs with limited battery life, such as pedestrians, bicycles, and electric vehicles. Therefore, the current sensing-based resource selection method is challenging in terms of power consumption or power efficiency of the radio resource selection procedure when applied to these UEs.

[0025] Figure 4 shows a sensing process for autonomous resource selection that can be performed by the UE. Figure 4 shows a sensing window 220 with its start 220a and its end 220b, and a selection window 222 with its start 222a and its end 222b. A plurality of time slots 224 are shown, and it can be seen that the sensing window 220 and the selection window 222 span a certain number of time slots 224. Figure 4 Further shown is time slot n at 226, i.e., the time slot that triggers the transmission to be performed by the UE. Note that the UE does not necessarily have to perform sensing during the entire sensing window, but can be configured to perform partial sensing only using periodic or aperiodic sub-intervals within the sensing window. The reason may be that the UE has to perform energy conservation and may rely on a subset of the sensing results.

[0026] For example, the trigger can be that the UE determines that the buffer includes data or data packets to be transmitted. In response to this determination or trigger, at time slot n, the UE selects resources to be used for transmitting the data or data packets in the transmission buffer. The selection is based on the resource information obtained during the sensing window 220. According to other examples, the output of the data at time slot n can be triggered by the following events:

[0027] · From the perspective of the Medium Access Control (MAC) layer, when a Protocol Data Unit (PDU) is generated by the MAC layer and is available for the Physical (PHY) layer,

[0028] · From the perspective of the application layer, when an event (ranging from the availability of sensor information to be shared to unexpected events such as accidents) generates data that needs to be transmitted.

[0029] The sensing process is that the Mode 2 UE considers, for example, the first-stage SCI received from other UEs to identify the resources reserved by these other UEs in the recent past. The UE also measures the Sidelink (SL) Reference Signal Received Power (RSRP) in the time slots that define the sensing window 220 to determine the interference level when the UE uses these resources for transmission. This enables the UE to identify the resources available for transmission and the resources not available for transmission. When the UE intends to perform a transmission, for example, in response to a trigger event at time slot n, it triggers the resource selection process, where the UE considers the sensing results within a past period of time before the trigger for transmission or resource selection. The past period of time just mentioned is the sensing window 220, which is the period of time during which the UE considers the sensing results therein to determine the possible resources for transmission. As Figure 4 shown, the sensing window 220 starts at a certain time 220a in the past with reference to the time slot n that triggers the transmission. The period of time starting from the time slot n at which the sensing window 220 starts is time T0, which has a certain configured or pre-configured length, such as 1100 ms or only 100 ms. In Figure 4 the example, shortly before the trigger for the selection process or transmission at time slot n, the sensing window 220 ends at 220b. Figure 4 As shown in, the period of time between the end of the sensing window 220 and the time slot n is T proc,0 . According to other examples, the sensing window can end immediately at time slot n, making T proc,0 = 0. Therefore, the duration of the sensing window can be defined as [n - T0, n - T proc,0 .

[0030] T0 can be defined by a higher layer, for example, configured by the resource pool (RP) using the parameter sL-SensingWindow-r16. T0 can be between 100 ms and 1100 ms. The definition of T proc,0 can be as shown in the following table, depending on the subcarrier spacing used in the resource pool.

[0031] <![CDATA[μ SL > <![CDATA[T proc,0 [Time slot]]]> 0 1 1 1 2 2 3 4

[0032] The result generated by the sensing process is referred to as the sensing result. The sensing result indicates whether certain resources are available or unavailable for transmission for a set of time and frequency resources. The indicated resources can be located within a specific resource pool, such as the sidelink resource pool of a wireless communication system, and are distributed over a specific duration in the past, i.e., the sensing window 220. The sidelink resource pool can be a transmission resource pool, a reception resource pool, an exception resource pool, a resource pool for mode 1, and a resource pool for mode 2.

[0033] Based on the information obtained from the sensing process, for a transmission triggered at time slot n, the UE selects resources within the selection window 222. As Figure 4 shown, the selection window 222a starts shortly after the transmission or resource selection is triggered, e.g., after a time period T1 following time slot n. In other examples, the selection window 222 can start immediately at time slot n, making T1 = 0. The end of the selection window 222b is the time T2, which is determined, for example, by the packet delay budget PDB associated with the data or packet or transport block TB to be transmitted by the UE. The selection window 222 is the time period during which the UE selects resources by considering the sensing information, extrapolating available resources based on the sensing information to generate a candidate resource set, and selecting resources for the triggered transmission within the candidate resource set.

[0034] The duration of the selection window 222 can be defined by [n + T1, n + T2], where T1 and T2 can be defined according to the UE implementation. T1 can be as follows: 0 < T1 < T proc,1 where T proc,1 can be defined with reference to the subcarrier spacing of the resource pool from which resources for transmission are selected as shown in the following table.

[0035] <![CDATA[μ SL > <![CDATA[T proc,1 [Time Slot]]]> 0 3 1 5 2 9 3 17

[0036] T2 can be defined based on the packet delay budget PDB and T2 min while T2 min can be defined by a higher layer, e.g., using the resource pool RP configuration, through the parameter SL - SelectionWindow - r16, and can take values between 1, 5, 10, and 20 milliseconds, depending on the priority of the data or packet to be transmitted by the UE. For example, in the case where T2 < the remaining PDB, the following holds:

[0037] · If T2 < the remaining PDB, T2 min ≤ T2 ≤ the remaining PDB

[0038] · Otherwise, T2 = the remaining PDB

[0039] Using the defined sensing and selection window, the UE autonomously selects resources as follows. All resources within the selection window 222 are initially considered candidate resources that can be used by the UE for transmission. Therefore, the UE collects all resources within one or more time slots and within one or more subchannels to form a candidate resource set S A , the candidate resource set S A has a size given by M total based on the number of resources within the set. Then, the UE continues to exclude certain resources from the candidate resource set until it arrives at the final candidate resource set, denoted as S B . The number of resources in the final candidate resource set S B can be less than the number of resources M A in the original candidate resource set S total .

[0040] Resources can be excluded in the presence of certain conditions. For example, when the UE sends another transmission in a given time slot and does not receive anything due to the half-duplex constraint, the resources from the given time slot are excluded from the initial candidate resource set S A . In any case where a received SCI indicates a resource reservation period, the UE excludes any future resources indicated by that reservation period from the initial candidate resource set S A . When the RSRP measurement of a certain resource is higher than a threshold such as the SL-RSRP threshold, the UE excludes that resource from the initial candidate resource set S A , and this threshold can be set using the priority value received in the SCI and the priority value associated with the triggered transmission. Resources indicated in the received SCI and extrapolated for future periodic transmissions can also be excluded.

[0041] In the case where the size of the final candidate resource set S B is less than a certain percentage of the total number of available resources in the selection window, it is determined that there are not enough resources for the UE to select for performing the triggered transmission. In this case, the UE reduces the SL-RSRP threshold and repeats the selection process based on any of the above conditions. The percentage just mentioned can be represented by X, and the size of the final candidate set is not less than X·M total . Once the final candidate resource set S B is determined by the UE, the UE sends the final candidate resource set S B to a higher layer. For example, the higher layer selects the required number of resources from the final candidate resource set S B based on a uniform distribution, and then these selected resources are used by the UE for the triggered transmission.

[0042] For example, for LTE V2X Mode 4 (see 3GPP 36.213) and NR V2X Mode 2 (see 3GPP 38.214), the following radio resource selection procedures are performed:

[0043] · Randomly select radio resources;

[0044] · Radio resource selection based on periodic sensing, and

[0045] · Radio resource selection based on partial sensing

[0046] When the higher layer signaling configures random radio resource selection, the user transmits on the configured bandwidth part. The 3GPP 38.214 specifies the resource selection procedure as follows:

[0047] 1. The candidate resource set R xy is a set of L consecutive subchannels x + j, where j = 0, …, L - 1 is a set of consecutive subchannels in the subframe at time t m within the time interval [n + T1, n + T2]. The timestamp n is the packet arrival time. T1 and T2 are the processing time and the packet delay budget respectively. The values of T1 and T2 depend on the UE implementation and need to satisfy the following conditions:

[0048] a. T1 ≤ 4 and T2 min (TX priority) ≤ T2 ≤ 100, where the higher layer provides the TX priority, otherwise T2 min is set to 20.

[0049] 2. Initialize all configured frequency-time resource sets Sa and create an empty set Sb.

[0050] 3. The UE selects a set of subframe resources R xy required for its transmission from the set Sa

[0051] to the set Sb.

[0052] When the higher layer configures partial sensing, the UE performs candidate radio resource selection according to 3GPP 36.213 as follows:

[0053] 1. The candidate resource set R xy is a set of L consecutive subchannels x + j, where j = 0, …, L - 1 is a set of consecutive subchannels in the subframe at time t m within the time interval [n + T1, n + T2]. The timestamp n is the packet arrival time.

[0054] The UE selects y subframes within the time interval [n + T1, n + T2], where y depends on the UE implementation. The higher layer signaling configures T1 and T2; their values depend on the UE implementation. T2 is a value between min (the priority of TX) and 100 ms. T2min is configured by the higher layer signaling, otherwise T2 min defaults to 20 ms. In addition, the upper bound of T2 depends on the maximum delay allowed for the packet to wait in the UE buffer before transmission. y is the implementation of the higher layer parameter minNumCandidateSF in M min , where M total is the total number of subframe resources. total

[0055] 2. The UE monitors all t y-k *P step subframe resources, where k is the 10-bit gapCandidatesensing configured by the higher layer signaling. P step is the step size between two consecutive sensing time instances configured.

[0056] 3. The bit set to 1 represents the sensing time instance monitored by the P-UE when partially sensing is configured.

[0057] 4. The parameter Th(a, b) is configured differently by the higher layer according to the priority requirements of the application.

[0058] 5. Sa is a list of all radio resource subframes, and Sb is an empty set.

[0059] 6. The UE excludes any subframe resource from the set Sa that satisfies all of the following conditions:

[0060] a. The UE decodes SCI format 1, indicating resource reservation and priority, i.e., including the "resource reservation" and "priority" fields. The parameter priorx is derived from the "priority" field.

[0061] b. The measured PSSCH-RSSP of m is higher than the Th(priotx, priorx) value.

[0062] c. The UE receives SCI format 1 on subframe t m+q *P step *Prsvp RX , indicating the number of reserved resources with higher priority overlapping with R x,y+j *P’rsvp TX , where q = 1, 2,..., Q and j = 0, 1,..., Cresel - 1. If Prsvp RX < 1 and y - m ≤ Pstep * Prsvp RX + Pstep, then the value Q = 1 / PrsvpRX If ty is the last subframe in the Y subframes, Q = 1. Where P’rsvp TX and P’rsvp RX are the reserved resources indicated by the transmitter and receiver users respectively. C resel is the number of resources selected for semi-persistent scheduling defined in 3GPP 38.321.

[0063] 7. If the number of candidate radio resource subframes identified in the Sb set is less than 0.2 * M total , then increase Th(a, b) in step 4 by 3 dB.

[0064] 8. For the remaining R xy subframe resources in the Sa set, the metric E xy is defined as the average S-RSSI of subchannels x + k in subframe resource ty - Pstep * j, k = 0, …, L - 1.

[0065] 9. The UE moves the candidate resource with the minimum E xy from Sa to Sb so that the number of available subframe resources in Sb reaches 0.2 * M total .

[0066] 10. In the multi-carrier case, when the UE does not support the multi-carrier feature, the UE removes the subframe resource R xy from Sb.

[0067] The UE reports the Sb set to the higher layer.

[0068] In NR V2X mode 2 of Release 16, LTE V2X mode 4 is enhanced by supporting, for example, different V2X traffic types (such as aperiodic traffic and periodic traffic) and different broadcast communications (such as broadcast, unicast, multicast). The radio resource selection process in NR-V2X mode 2 specified in 3GPP 38.214 is now described in more detail.

[0069] When reporting subframe resources that can be used by the higher layer for control or data transmission, the UE considers some parameters, such as priorities for reception and transmission, configured resource pools, packet delay budgets, and radio resource reservations. For example, the UE considers the following parameters during subframe resource selection:

[0070] · T2min_SelectionWindow:

[0071] The minimum time used in the resource selection window and configured by the higher layer.

[0072] · SL-ThresRSRP_pi_pj:

[0073] The RSRP threshold of the priority pi received in SCI format 0-1, and the RSRP threshold of the transmission priority pj configured by the higher layer.

[0074] · RSRP for sensing:

[0075] This determines the RSRP in the control or data channel to be considered.

[0076] · T0_Sensing_Window:

[0077] This is the number of time slots of the measurement considered in the candidate resource selection process.

[0078] · reservationPeriodAllowed

[0079] In addition, Prsvp TX is the transmission reservation period, which can be converted to the logical time slot P’rsvp when needed tx .

[0080] Similar to LTE V2X mode 4 (see 3GPP36.213), in NR V2X mode 2 (see 3GPP38.214), the resource selection process is performed as follows:

[0081] 1. The UE selects the time-frequency resource R xy for transmission, which consists of L consecutive radio resources starting from x + j, where j = 0, 1,..., L - 1. The UE selects the time slots between [n + T1, n + T2] regarding the resource pool, where the values of T1 and T2 depend on the UE implementation, and T2 can be between T2 min and the packet delay budget PDB at the time of configuration T2 min . Otherwise, it is set to the remaining PDB. M total is the total number of available radio resources for transmission.

[0082] 2. As mentioned before, the UE monitors the time slots within the sensing window.

[0083] 3. Th(pri) is the received signal strength associated with the applied QoS requirements and is configured by the higher layer.

[0084] 4. All radio resources include the Sa set.

[0085] 5. When the following conditions are met, the UE excludes R xy from Sa:

[0086] a. The UE does not monitor the time slot.

[0087] b. SCI format 0-1 indicates that the "resource reservation period" is set and there are no available sub-channels in a certain time slot.

[0088] c. The SCI format 0-1 indicates reserved radio resources, and the priority value is higher than the transmission priority.

[0089] d. The measured RSRP value is higher than Th(prior RX ) received in the SCI format 0-1.

[0090] e. Set the "resource reservation period" field on the received SCI format 0-1 that overlaps with R xy +jP’rsvp TX where q = 1, 2,..., Q and j = 0, 1, 2,..., C m+q *P’rsvp RX -1. P’rsvp resel is the logical time slot obtained from Prsvp RX When Rrsvp RX <Tscal, Q = Roof(Tscal / Prscvp RX ) where Tscal is the remaining time of the packet delay budget, and n’ ≤ m + P’rsvp RX where when the time slot n belongs to the reserved transmission time period, n = n', otherwise it is the first time slot after n in the configured transmission time slot range. RX

[0091] f. When the number of candidate time slot resources is less than 0.2*M total , then Th(pri) is increased by 3 dB, and the resource selection process starts from step 4.

[0092] The UE reports Sa to the higher layer.

[0093] When configuring the resource pool, different resource selection strategies are allowed within the resource pool, such as partial sensing, random sensing, and normal sensing. However, energy-saving users may select radio resources reserved by other nearby UEs such as V-UEs, resulting in conflicts. To avoid such conflicts, in addition to the preemption and re-evaluation features of V-UE users, energy-saving users can also use continuous partial sensing to reduce conflicts caused by the non-periodic traffic generated by other energy-saving users. Figure 5 Shows an example of continuous partial sensing in an energy-saving V-UE. Through continuous partial sensing, the energy-saving user can immediately continue continuous sensing after the resource selection trigger time n at 226 until the actual resource transmission time T2. In Figure 5 , during the sensing window 220, the UE senses in the subframe or time slot 228 and does not sense in the subframe or time slot 230. At 226, the continuous sensing window 234 has a range from t a to t b ​Size. During the continuous sensing window 234, the UE continuously senses resources. In this way, the power-saving UE can identify resources that nearby power-saving users may reserve.

[0094] Although the above method solves some power consumption problems, it still does not provide the power savings required for battery-driven UEs such as V2X UEs that send / receive via SL.

[0095] Embodiments of the present invention provide improvements and enhancements by utilizing current resource selection strategies and refining different conditions that trigger different selection strategies, such as random or partial sensing using different numbers of sensing measurements, to extend battery life and save user power. Embodiments of the present invention avoid the problem of an increased probability of conflicts occurring between users with different resource selection strategies due to the use of resource pools that support different resource selection strategies, and provide a selection of appropriate resource selection strategies to save energy while maintaining reliability and latency. Embodiments of the present invention provide a method for energy-efficient resource selection. More specifically, embodiments provide improvements to the resource selection process related to random resource selection, partial sensing, or sensing for power-saving users in NR side links, while some embodiments also consider discontinuous reception DRX.

[0096] Embodiments of the present invention propose a mechanism for reducing UE power consumption, for example, based on a decision of whether to apply random selection or sensing or partial sensing, such as using an optimal number of sensing instances. The following embodiments or aspects relate to technologies for utilizing current resource selection and reducing energy consumption for power-saving users:

[0097] · Embodiment 1:

[0098] Random selection of periodic or aperiodic traffic based on traffic / user density.

[0099] · Embodiment 2:

[0100] Random resource selection for power-saving users in a resource pool configured for random resource selection and sensing-based resource selection.

[0101] · Embodiment 3:

[0102] Resource selection based on received ACK / NACK.

[0103] · Embodiment 4:

[0104] Continuous partial sensing trigger condition.

[0105] · Embodiment 5:

[0106] Adaptive continuous partial sensing for power-saving users.

[0107] · Embodiment 6:

[0108] UE Power Saving Based on Absolute or Relative UE Position

[0109] · Example 7:

[0110] Sensing Extension and DRX-On-Off Adaptation.

[0111] Embodiments of the present invention are advantageous because partial sensing and random resource selection on the direct link, as well as DRX on / off durations, result in reduced power consumption of the UE. Energy conservation of battery-based UEs using V2X applications (which is typically related to V2X security) is highly beneficial for ensuring that the UE does not deplete its battery. Additionally, the improved reliability and reduced latency also meet the needs of energy-saving users.

[0112] Embodiments of the present invention can be implemented in a wireless communication system as described above, which includes a base station and users, such as mobile terminals or IoT devices. Figure 6 is a schematic diagram of a wireless communication system, including a transmitter 300 such as a base station and one or more receivers 302, 304 such as user equipment UEs. The transmitter 300 and the receivers 302, 304 can communicate via one or more wireless communication links or channels 306a, 306b, 308, such as radio links. The transmitter 300 may include one or more antennas ANT T or an antenna array having multiple antenna elements, a signal processor 300a, and a transceiver 300b. The receivers 302, 304 include one or more antennas ANT UE or an antenna array having multiple antennas, signal processors 302a, 304a, and transceivers 302b, 304b. The base station 300 and the UEs 302, 304 can communicate via respective first wireless communication links 306a and 306b, such as radio links using the Uu interface, while the UEs 302, 304 can communicate with each other via a second wireless communication link 308, such as a radio link using the PC5 / direct link SL interface. When the UEs are not served by a base station or not connected to a base station, for example, they are not in the RRC connected state, or, more generally, when the base station does not provide SL resource allocation configuration or assistance, the UEs can communicate with each other via the direct link SL. Figure 6 of the system or network, Figure 6 one or more UEs 302, 304, Figure 6 the base station 300 can operate according to the teachings of the present invention described herein.

[0113] Apparatus

[0114] ---------------------------------------------------------------------

[0115] Example 1

[0116] --------------------------------------------------------------------- The present invention provides a user equipment UE for a wireless communication network, the wireless communication network including a plurality of user equipments UE, wherein the UE is for communicating with one or more other user equipments UE of the wireless communication network via a direct link, wherein, in response to a trigger for transmission, the UE performs a sensing process for determining resources to be used for transmission, the sensing process including a plurality of radio resource selection processes, and wherein the UE is for selecting a radio resource selection process to be applied from the plurality of radio resource selection processes according to one or more of the following:

[0117] · Traffic density,

[0118] · Traffic density of different types of traffic,

[0119] · User density within a predefined area around the UE.

[0120] According to an embodiment, the UE is for determining traffic density and / or user density using measurements of one or more channel metrics such as channel busy ratio CBR during a predefined period before the start of a radio resource selection process.

[0121] According to an embodiment, the UE is for

[0122] · Performing measurements of one or more channel metrics, and / or

[0123] · Obtaining measurements of one or more channel metrics from one or more network entities within a predefined area, for example, obtaining from one or more of other UEs via inter-UE signaling, or obtaining from a roadside unit RSU operating in mode 2, or obtaining from a base station such as a gNB operating in mode 1.

[0124] According to an embodiment, the UE is for selecting resources from a resource pool of the wireless communication network shared by a plurality of user equipments, wherein the resource pool is to be used for some or all of a plurality of radio resource selection processes.

[0125] According to an embodiment, the plurality of radio resource selection processes include:

[0126] · Random radio resource selection;

[0127] · Radio resource selection based on periodic sensing, and

[0128] · Radio resource selection based on partial sensing.

[0129] According to an embodiment, different types of traffic include:

[0130] · Periodic traffic, and

[0131] · Aperiodic traffic.

[0132] According to an embodiment, the UE is used when

[0133] · The density of periodic traffic reaches or is lower than a first threshold, and

[0134] · The density of aperiodic traffic reaches or is higher than a second threshold, where the second threshold is higher than the first threshold, and

[0135] · The user density reaches or is lower than a third threshold,

[0136] Select random radio resource selection or radio resource selection based on partial sensing or radio resource selection based on periodic sensing.

[0137] According to an embodiment, the UE is used to select random radio resource selection or radio resource selection based on partial sensing when the density of traffic associated with random radio resource selection and traffic associated with radio resource selection based on partial sensing, such as the channel busy rate CBR, reaches or is lower than a certain limit or threshold, where the limit or threshold can be pre-configured or configured by higher layer signaling, such as RRC, SIB, PC5-RRC signaling, received from one or more network entities, such as from a roadside unit RSU or from a base station such as a gNB.

[0138] ---------------------------------------------------------------------

[0139] Embodiment 2

[0140] --------------------------------------------------------------------- The present invention provides a user equipment (UE) for a wireless communication network, the wireless communication network including a plurality of user equipments (UEs), where the UE is for communicating with one or more other user equipments (UEs) of the wireless communication network via a direct link, where the wireless communication network provides a resource pool shared by a plurality of user equipments, and the resource pool will be used for some or all of a plurality of radio resource selection processes, and where, if the UE is for performing a sensing process for determining a resource to be used for transmission using a specific radio resource selection process such as random radio resource selection, in response to a trigger for transmission, the UE does not perform the sensing process and selects a resource for the triggered transmission from a set of predefined resources within the resource pool.

[0141] According to an embodiment, resources of a set of predefined resources are selected from the resource pool according to one or more predefined criteria, such as according to one or more of the following:

[0142] · Quality of Service (QoS) associated with the transmission,

[0143] · Priority of the transmission,

[0144] · Geographic area where the UE is located, such as the cell or minimum communication range (MCR) of the UE, or the relative position or absolute position of the UE,

[0145] · Traffic density,

[0146] · User density within a predefined area around the UE,

[0147] · Type of the UE, such as a vehicular UE or a battery-based UE.

[0148] According to an embodiment, the plurality of radio resource selection processes for which the resource pool is configured at least includes or only includes:

[0149] · Random radio resource selection, and

[0150] · Radio resource selection based on periodic sensing, and

[0151] where the radio resource selection process includes random radio resource selection.

[0152] According to an embodiment, the predefined resources include predefined time-frequency resources, and the UE is configured or preconfigured with the time-frequency resources via a higher layer, for example, by RRC or DCI or SCI signaling.

[0153] ---------------------------------------------------------------------

[0154] Embodiment 3

[0155] --------------------------------------------------------------------- The present invention provides a user equipment UE for a wireless communication network, the wireless communication network including a plurality of user equipments UE, wherein the UE is configured to communicate with one or more other user equipments UE of the wireless communication network via a direct link, wherein, in response to a trigger for transmission, the UE performs a sensing process for determining resources to be used for transmission, the sensing process including one of a plurality of radio resource selection processes, and wherein the UE does not select or exclude resources associated with feedback indicating an unsuccessful earlier transmission on the resources as resources for transmission.

[0156] According to an embodiment, the feedback includes, for example, one or more NACK messages transmitted by an intended receiver in unicast and multicast manners or transmitted by nearby UEs via inter-UE coordination messages.

[0157] According to an embodiment, the UE is configured to select resources from a resource pool of the wireless communication network shared by a plurality of user equipments, wherein the resource pool will be used by each of a plurality of radio resource selection processes, and wherein the plurality of radio resource selection processes may include:

[0158] · Random radio resource selection;

[0159] · Periodic sensing-based radio resource selection, and

[0160] · Partial sensing-based radio resource selection.

[0161] ---------------------------------------------------------------------

[0162] Embodiment 4

[0163] --------------------------------------------------------------------- The present invention provides a user equipment UE for a wireless communication network, the wireless communication network including a plurality of user equipments UE, wherein the UE is configured to communicate with one or more other user equipments UE of the wireless communication network via a direct link, wherein, in response to a trigger for transmission, the UE performs a sensing process for determining resources to be used for transmission, and wherein the UE is configured to trigger a partial sensing-based radio resource selection for selection from the sensed resources in response to meeting one or more predefined criteria.

[0164] According to an embodiment, one or more predefined criteria include one or more of the following:

[0165] · The non-periodic traffic density exceeds a defined or specified threshold level,

[0166] · If one or more quality of service (QoS) requirements are not met,

[0167] · The UE is located within or close to a certain geographical area, such as a geographical area that may trigger an increased amount of non-periodic traffic.

[0168] According to an embodiment, the UE is configured to apply partial sensing-based radio resource selection and switch to continuous partial sensing-based radio resource selection only when one or more criteria are met.

[0169] According to an embodiment, according to continuous partial sensing-based radio resource selection, after a trigger for transmission, the UE performs sensing during a continuous sensing window until a predefined time before transmission.

[0170] According to an embodiment, the UE is configured to select resources from a resource pool of a wireless communication network shared by a plurality of user equipments, where the resource pool will be used by each of a plurality of radio resource selection processes, and the plurality of radio resource selection processes may include one or more of the following:

[0171] · Random radio resource selection,

[0172] · Periodic sensing-based radio resource selection, and

[0173] · Partial sensing-based radio resource selection.

[0174] ---------------------------------------------------------------------

[0175] Embodiment 5

[0176] --------------------------------------------------------------------- The present invention provides a user equipment (UE) for a wireless communication network, the wireless communication network including a plurality of user equipments (UEs), wherein the UE is configured to communicate with one or more other user equipments (UEs) of the wireless communication network via a direct link, wherein, in response to a trigger for transmission, the UE performs a sensing process for determining resources to be used for transmission, the sensing process including radio resource selection based on successive partial sensing, and wherein the size of a successive sensing window during radio resource selection based on successive partial sensing is set depending on one or more predefined criteria.

[0177] According to an embodiment, the one or more predefined criteria include one or more of the following:

[0178] · One or more quality of service (QoS) requirements associated with the transmission,

[0179] · One or more transmission parameters, such as HARQ feedback channel configuration,

[0180] · Other parameters, such as the relative or absolute speed of the UE.

[0181] According to an embodiment, the successive sensing window starts at a predetermined time before or after the trigger for transmission and ends at a predetermined time before the transmission.

[0182] According to an embodiment, the UE is configured to select resources from a resource pool of the wireless communication network shared by a plurality of user equipments, wherein the resource pool will be used by each of a plurality of radio resource selection processes, and wherein the plurality of radio resource selection processes may include one or more of the following:

[0183] · Random radio resource selection;

[0184] · Radio resource selection based on periodic sensing; and

[0185] · Radio resource selection based on partial sensing.

[0186] ---------------------------------------------------------------------

[0187] Embodiment 6

[0188] --------------------------------------------------------------------- The present invention provides a user equipment (UE) for a wireless communication network, the wireless communication network including a plurality of user equipments (UEs), wherein the UE is configured to communicate with one or more other user equipments (UEs) of the wireless communication network via a direct link, and wherein, based on the location of the UE, the UE performs or does not perform or modifies at least one or more operations associated with the direct link communication.

[0189] According to an embodiment, one or more operations associated with the direct link communication include one or more of the following:

[0190] · A sensing process for determining resources to be used for a triggered transmission,

[0191] · Resource selection for the triggered transmission;

[0192] · The triggered transmission,

[0193] · Reception of the transmission,

[0194] · Signal processing,

[0195] · Discontinuous reception (DRX) mode.

[0196] According to an embodiment, the location of the UE is an absolute location and / or a relative location, and wherein the location of the UE is based on one or more of the following:

[0197] · Geographic location or absolute location, e.g., based on a Global Navigation Satellite System (GNSS),

[0198] · Relative location or distance, e.g., a specific distance to a road, or an intersection, or a Road Side Unit (RSU) or another UE,

[0199] · Geographic area, e.g., one or more zones, identified by a zone ID.

[0200] According to an embodiment,

[0201] · When the UE is at or near a first location, the UE does not perform or modifies at least one or more operations associated with the direct link communication, and

[0202] · When the UE is at or near a second location, the UE resumes at least one or more operations associated with the direct link communication.

[0203] According to an embodiment,

[0204] · Being at the first location includes an area where direct link (SL) services such as V2X services are not required, and

[0205] · Being at the second location includes an area where direct link (SL) services such as V2X services are required.

[0206] According to an embodiment, the UE is used to communicate with one or more other network entities of a radio communication network, such as a base station, via the Uu interface, and wherein, depending on the location of the UE, the UE performs, does not perform, or modifies at least one or more operations associated with the Uu interface.

[0207] ---------------------------------------------------------------------

[0208] Embodiment 7

[0209] --------------------------------------------------------------------- The present invention provides a user equipment UE for a wireless communication system, the wireless communication system including a plurality of user equipments UE, wherein the UE is used to communicate with one or more other user equipments UE of the wireless communication network via a direct link, wherein the UE is used to operate in a discontinuous reception DRX mode, wherein, in response to a trigger for transmission, the UE performs a sensing process for determining a resource to be used for transmission, and wherein the UE is configured or pre-configured with parameters that, in response to a trigger for transmission, cause an extension of a default wake-up duration (ON duration) of a DRX cycle according to a sensing window of the sensing process, the sensing window having a size or duration specified by the triggered transmission.

[0210] According to an embodiment, the default wake-up duration of a DRX cycle includes a default start time and a default end time, and wherein the extension of the default wake-up duration includes one or more of the following to ensure that the UE can perform a sensing process for a specified sensing window size:

[0211] · An offset of the default end time to a later time;

[0212] · An offset of the default start time to an earlier time.

[0213] According to an embodiment, the UE is configured or pre-configured with parameters via RRC or PC5-RRC signaling or DCI or SCI or MAC signaling.

[0214] According to an embodiment, the UE is configured or pre-configured with a plurality of parameters, each parameter defining a different extension of the wake-up duration, and wherein the UE is used to select a parameter to be applied according to one or more predefined criteria.

[0215] According to an embodiment, one or more predefined criteria include one or more of the following:

[0216] ·One or more quality of service (QoS) requirements associated with the transmission,

[0217] ·One or more transmission parameters, such as HARQ feedback channel configuration,

[0218] ·Priority of the transmission,

[0219] ·Geographical area where the UE is located, such as the cell or minimum communication range (MCR) of the UE, or the relative or absolute position of the UE,

[0220] ·Traffic density,

[0221] ·User density within a predefined area around the UE,

[0222] ·Type of the UE, such as a vehicular UE or a battery-based UE.

[0223] The present invention provides a user equipment (UE) for a wireless communication system, the wireless communication system including a plurality of user equipments (UEs), wherein the UE is for communicating with one or more other user equipments (UEs) of the wireless communication network via a direct link, wherein the UE operates in a discontinuous reception (DRX) mode, wherein, in response to a trigger for transmission, the UE performs a sensing process for determining resources to be used for the transmission, the sensing process including a radio resource selection process based on continuous partial sensing, and wherein the UE is for adjusting a continuous sensing window so as to initiate the radio resource selection process based on continuous partial sensing before the start of the DRX wake-up duration.

[0224] According to an embodiment, the UE is for determining the time at which the continuous sensing window starts before the start of the DRX wake-up duration based on one or more parameters associated with the triggered transmission, such as the QoS or priority associated with the transmission.

[0225] ---------------------------------------------------------------------

[0226] General --------------------------------------------------------------------- According to an embodiment, the UE is for

[0227] ·Communicating with one or more other UEs using a direct link SL interface such as a PC5 interface, and / or

[0228] · Communicate with one or more radio access network (RAN) entities of a wireless communication system, such as one or more base stations, using a radio interface such as the Uu interface, or using a shared access band such as an unlicensed band.

[0229] System

[0230] The present invention provides a wireless communication system, including one or more user equipments (UEs) of the present invention.

[0231] Method

[0232] ---------------------------------------------------------------------

[0233] Example 1

[0234] --------------------------------------------------------------------- The present invention provides a method for operating a user equipment (UE) of a wireless communication network, the wireless communication network including a plurality of UEs, wherein the UE communicates with one or more other UEs of the wireless communication network via a direct link. The method includes: in response to a trigger for transmission, performing a sensing process for determining resources to be used for transmission, the sensing process including a plurality of radio resource selection processes, and selecting a radio resource selection process to be applied from the plurality of radio resource selection processes according to one or more of the following:

[0235] · Traffic density,

[0236] · Traffic density of different types of traffic,

[0237] · User density within a predefined area around the UE.

[0238] ---------------------------------------------------------------------

[0239] Example 2

[0240] --------------------------------------------------------------------- The present invention provides a method for operating a user equipment (UE) for a wireless communication network, the wireless communication network including a plurality of user equipments (UEs), wherein the UE is for communicating with one or more other user equipments (UEs) of the wireless communication network via a direct link, and wherein the wireless communication network provides a resource pool shared by the plurality of user equipments and to be used for some or all of a plurality of radio resource selection processes. The method includes: if the UE is for performing a sensing process for determining a resource to be used for transmission using a specific radio resource selection process, such as random radio resource selection, then in response to a trigger for transmission, not performing the sensing process and selecting a resource for the triggered transmission from a set of predefined resources within the resource pool.

[0241] ---------------------------------------------------------------------

[0242] Embodiment 3

[0243] --------------------------------------------------------------------- The present invention provides a method for operating a user equipment (UE) for a wireless communication network, the wireless communication network including a plurality of user equipments (UEs), wherein the UE is for communicating with one or more other user equipments (UEs) of the wireless communication network via a direct link. The method includes: in response to a trigger for transmission, performing a sensing process for determining a resource to be used for transmission, the sensing process including one of a plurality of radio resource selection processes, and not selecting or excluding a resource associated with feedback indicating an unsuccessful earlier transmission on the resource as a resource for transmission.

[0244] ---------------------------------------------------------------------

[0245] Embodiment 4

[0246] --------------------------------------------------------------------- The present invention provides a method for operating a user equipment (UE) of a wireless communication network, the wireless communication network including a plurality of user equipments (UEs), wherein the UE is used to communicate with one or more other user equipments (UEs) of the wireless communication network via a direct link. The method includes: in response to a trigger for transmission, performing a sensing process for determining resources to be used for transmission, and in response to meeting one or more predefined criteria, triggering a radio resource selection based on continuous partial sensing to select from the sensed resources.

[0247] ---------------------------------------------------------------------

[0248] Embodiment 5

[0249] --------------------------------------------------------------------- The present invention provides a method for operating a user equipment (UE) of a wireless communication network, the wireless communication network including a plurality of user equipments (UEs), wherein the UE is used to communicate with one or more other user equipments (UEs) of the wireless communication network via a direct link. The method includes: in response to a trigger for transmission, performing a sensing process for determining resources to be used for transmission, the sensing process including a radio resource selection based on continuous partial sensing, and setting the size of a continuous sensing window during the radio resource selection based on continuous partial sensing depending on one or more predefined criteria.

[0250] ---------------------------------------------------------------------

[0251] Embodiment 6

[0252] --------------------------------------------------------------------- The present invention provides a method for operating a user equipment (UE) of a wireless communication network, the wireless communication network including a plurality of user equipments (UEs), wherein the UE is used to communicate with one or more other user equipments (UEs) of the wireless communication network via a direct link. The method includes: performing, not performing, or modifying at least one or more operations associated with direct link communication according to the location of the UE.

[0253] ---------------------------------------------------------------------

[0254] Example 7

[0255] --------------------------------------------------------------------- The present invention provides a method for operating a user equipment (UE) of a wireless communication system, the wireless communication system including a plurality of user equipments (UEs), wherein the UE is configured to communicate with one or more other user equipments (UEs) of the wireless communication network via a direct link, and wherein the UE is configured to operate in a discontinuous reception (DRX) mode. The method includes: in response to a trigger for transmission, performing a sensing process for determining resources to be used for transmission, and in response to the trigger for transmission and according to configured or pre-configured parameters, extending a default wake-up duration of a DRX cycle according to a sensing window of the sensing process, the sensing window having a size or duration specified by the triggered transmission.

[0256] The present invention provides a method for operating a user equipment (UE) of a wireless communication system, the wireless communication system including a plurality of user equipments (UEs), wherein the UE is configured to communicate with one or more other user equipments (UEs) of the wireless communication network via a direct link, and wherein the UE operates in a discontinuous reception (DRX) mode. The method includes: in response to a trigger for transmission, performing a sensing process for determining resources to be used for transmission, the sensing process including a radio resource selection process based on consecutive partial sensing, and adjusting a consecutive sensing window so as to initiate the radio resource selection process based on consecutive partial sensing before the start of a DRX wake-up duration.

[0257] Computer program product

[0258] An embodiment of the present invention provides a computer program product including instructions which, when executed by a computer, cause the computer to execute one or more methods according to the present invention.

[0259] Embodiment 1: Random selection of periodic or aperiodic traffic based on traffic / user density.

[0260] Embodiments of the first aspect of the present invention provide a UE that can determine to select a random, sensing-based, or partial-sensing-based resource selection from a shared resource pool based on the traffic density of different traffic types (e.g., channel busy rate CBR, CBR_P for periodic traffic, or CBR_A for aperiodic traffic), and / or based on the measurement CBR_(R+P) of the user density of users performing random or partial sensing. The resource pool can be configured for random, sensing-based, or partial-sensing-based resource selection. For example, the UE can select a radio resource selection process to be used from multiple radio resource selection processes according to one or more of the following:

[0261] · Traffic density,

[0262] · Traffic density of different types of traffic,

[0263] · User density within a predefined area around the UE.

[0264] According to an embodiment, before resource selection begins, e.g., before transmission is triggered at the UE, measurements are provided by short sensing, e.g., within 100 time slots or fewer. According to other embodiments, the measurement information can be provided by other nearby UEs, e.g., using inter-UE signaling, or by an RSU operating in mode 2 or a gNB operating in mode 1. For example, in the case of CBR_P = 10%, i.e., the CBR for periodic traffic, CBR_A = 90%, i.e., the CBR for aperiodic traffic, and sparsely distributed users, the algorithm can select random selection or partial sensing for periodic or aperiodic traffic, thus avoiding performing regular sensing or adjusting multiple sensing instances according to traffic density.

[0265] Figure 7 A block diagram of a traffic density-based resource selection mechanism according to an embodiment is shown. The above-mentioned algorithm 350 is provided, which receives the measurement CBR_P of periodic traffic, the measurement CBR_A of aperiodic traffic, and / or the measurement CBR_(R+P) of user density as inputs, as indicated at 352, and a resource pool configuration 354. Using the inputs, the algorithm 350 selects a random selection 356 or normal or partial sensing 358 and controls the UE accordingly when performing the resource selection process.

[0266] According to other embodiments, in order to limit the amount of random and partial sensing selections from a system-level perspective, when the corresponding CBR_(R+P) threshold of the random or partial sensing selection traffic in one or more resource pools is below a certain limit, random or partial sensing resource selection can be selected. The corresponding threshold of CBR_(R+P) can be configured or pre-configured by high-layer signaling, e.g., by RRC, SIB, PC5-RRC signaling, via a gNB, RSU, or other UE.

[0267] Embodiment 2: Random resource selection for energy-saving users in a resource pool configured for random and sensing-based resource selection Embodiment 3: Resource selection based on received ACK / NACK

[0268] Embodiments of the second aspect of the present invention provide a method for avoiding collisions between UEs that use different resource selection processes in a common resource pool.

[0269] According to an embodiment, one or more resource pools may be configured for random resource selection and sensing-based resource selection. Traditionally, two users performing random selection may conflict due to transmissions on the same radio resource. To avoid such conflicts, according to an embodiment, users based on random selection may select radio resources from a set of predefined radio resources within the resource pool. This may be used for non-periodic traffic or for periodic traffic. In other words, in response to a trigger for transmission, the UE does not perform a sensing process but selects a resource for the triggered transmission from a set of predefined resources within the resource pool. Thus, users based on random selection refrain from performing sensing and transmission on the predefined resources, thereby avoiding conflicts between all users based on random selection.

[0270] For example, when configuring the radio resource selection of users based on random selection, i.e., when selecting a set of predefined resources from the resource pool, one or more of the following parameters may be considered:

[0271] · Quality of Service (QoS) associated with the transmission,

[0272] · Priority of the transmission,

[0273] · Geographic area where the UE is located, such as the cell or minimum communication range (MCR) of the UE, or the relative or absolute position of the UE,

[0274] · Traffic density,

[0275] · User density within a predefined area around the UE,

[0276] · Type of the UE, such as a vehicle-mounted UE or a battery-based UE.

[0277] For example, users based on random selection with periodic traffic may be configured to transmit only on preconfigured frequency-time resources. In this way, conflicts between users based on random selection are avoided. According to an embodiment, only re-evaluation and preemption features are configured for normal sensing users so that normal sensing users can preempt radio resources or, when re-evaluating (when configured), can re-select radio resources reserved by power-saving users.

[0278] The time-frequency resources may be configured or preconfigured by a higher layer, such as via RRC, DCI, or SCI signaling.

[0279] Embodiment 4: Continuous partial sensing trigger condition

[0280] Embodiments of a third aspect of the present invention provide energy-saving users that perform resource selection and consider whether a transmission has been unsuccessfully received. For example, when enabled, the UE can consider negative acknowledgments NACKs and feedback that cause resource reselection or retransmission.

[0281] For example, when the RPs of a resource pool are configured for random, partial, and periodic sensing-based resource selection, the energy-saving user that performs resource selection can consider NACK feedback for resource reselection or retransmission, and the energy-saving UE excludes those resources on which it has received a NACK message and that trigger reselection or retransmission.

[0282] The NACK message can be received from the intended receiver of the transmission in unicast and multicast manners, or can be indicated by a nearby user via an inter-UE coordination message.

[0283] Figure 5

[0284] Embodiments of a fourth aspect of the present invention provide a method for reducing conflicts between UEs using different resource selection processes by, for example, selectively allowing a UE to switch to continuous partial sensing based on certain conditions.

[0285] In the art, it has so far been agreed to use continuous partial sensing to reduce conflicts between users based on partial sensing and normal sensing, especially in the case of non-periodic traffic. As described above with reference to Embodiment 5: Adaptive continuous partial sensing for energy-saving users When applying continuous partial sensing, the UE senses immediately after the resource selection trigger time in continuous partial sensing and ends before transmission. Although continuous partial sensing may increase the power consumption of the energy-saving UE due to the extended sensing duration, the reliability increases as more sensing information is used during resource selection.

[0286] Embodiments of the present invention provide a trade-off between reliability and power consumption for energy-saving users by allowing an energy-saving UE to trigger continuous partial sensing based on certain conditions or criteria, such as one or more of the following conditions:

[0287] · The non-periodic traffic density exceeds a defined or specified threshold level.

[0288] · If one or more quality of service QoS requirements are not met.

[0289] · The UE is located within or close to a certain geographical area, such as a geographical area that may trigger an increased amount of non-periodic traffic.

[0290] According to an embodiment, when the aperiodic traffic density exceeds a defined or specified threshold level, the energy-saving UE may perform continuous partial sensing. For example, the aperiodic traffic density may be obtained from sensing measurements, such as from CBR.

[0291] According to other embodiments, the energy-saving UE may perform continuous partial sensing due to QoS requirements, for example, when periodic partial sensing cannot meet the QoS.

[0292] According to a further embodiment, when the UE is located in or near a geographical area where an increasing amount of aperiodic traffic may be triggered, the energy-saving UE may trigger continuous partial sensing.

[0293] Figure 5

[0294] Embodiments of the fifth aspect of the present invention provide a method for a UE that allows radio resource selection based on continuous partial sensing to adjust or set the size of a continuous sensing window during the selection of radio resources based on continuous partial sensing according to one or more predefined criteria.

[0295] According to an embodiment, the resource pool may be configured for different radio resource selection strategies, such as sensing-based, random, and partial-sensing-based. However, due to the lack of knowledge of resource allocation to other UEs or applications, some partial-sensing users and energy-saving users based on random selection may increase conflicts. Embodiment 6: UE energy saving based on absolute or relative UE position Continuous partial sensing is shown for reducing conflicts between these users, especially when aperiodic traffic dominates. However, generally, the size of the continuous sensing window 234 is determined by predefined values indicating the start time and end time of the continuous sensing window 234.

[0296] For example, the sensing in continuous partial sensing may start before the time 226 when resource selection or transmission is triggered, i.e., at n - t a , or may start immediately after the time 226, i.e., at n + t a . The end time t b may be selected from a range of values up to the maximum delay allowed by the application layer (i.e., the packet delay budget).

[0297] According to an embodiment, the size t of the continuous sensing window 234 may be set or adjusted or configured according to one or more predefined criteria, such as one or more of the following b -t a :

[0298] · One or more quality of service QoS requirements associated with the transmission,

[0299] · One or more transmission parameters, such as HARQ feedback channel configuration,

[0300] · Other parameters, such as the relative or absolute speed of the UE.

[0301] For example, the size t of the continuous sensing window 234 b -t a can be configured in the following way:

[0302] (t b ,t a ) = f(QoS, transmission parameters), n - T 0,proc -T < t a < n + t b -T0 ,proc

[0303] where

[0304] T 0,proc is the processing time,

[0305] T can be any value, for example, in the range of 0 to 32 or 100 time slots or milliseconds,

[0306] n < t b < t y -T 0,proc , where t y is the selected time - frequency resource for data transmission from [T1, T2].

[0307] Embodiment 7: Sensing extension and DRX-On-Off adaptation

[0308] Embodiments of the sixth aspect of the present invention provide a method that allows a UE to decide whether to perform, not perform, or modify at least one or more operations associated with direct - link communication according to the position of the UE. For example, one or more of the following operations:

[0309] · A sensing process for determining the resources to be used for a triggered transmission,

[0310] · Resource selection for a triggered transmission,

[0311] · A triggered transmission,

[0312] · Reception of a transmission,

[0313] · Signal processing,

[0314] · Discontinuous reception DRX mode.

[0315] According to the embodiment, in order to reduce the power consumption of the UE, V2X services and applications can partially (e.g., within a specific time period or interval), or not perform at all one or more of the following:

[0316] ·Partial or all sensing,

[0317] ·Resource selection and transmission,

[0318] ·Receiving of transmission,

[0319] ·Message processing, at least for V2X applications for example.

[0320] This can be determined depending on the absolute or relative position of the UE. For example, when the UE is not near a traffic-related scenario, e.g., depending on the distance to an intersection and / or a road.

[0321] In the case where the UE operates in DRX, the DRX configuration can also be adjusted according to the absolute or relative position of the UE instead of suppressing signal reception or transmission. For example, the timer can be adjusted to increase the sleep mode in DRX.

[0322] According to an embodiment, the position of the UE is an absolute position and / or a relative position, and can be based on one or more of the following:

[0323] ·Geographical location or absolute position, e.g., based on the Global Navigation Satellite System (GNSS),

[0324] ·Relative position or distance, e.g., a certain distance to a road, or an intersection, or a Road Side Unit (RSU) or another UE,

[0325] ·Geographical area, e.g., one or more zones, identified by a zone ID.

[0326] According to an embodiment, the absolute and / or relative position of the UE can be based on the geographical location or absolute position, e.g., based on GNSS or any other positioning method. For example, operations associated with direct link communication may not be performed inside a building where V2X services are not expected. This is typically relevant for battery-based UEs such as P-UEs. When the geographical location is in a place where V2X traffic may be irrelevant, e.g., in a forest or a pedestrian area, operations associated with direct link communication may also not be performed outdoors.

[0327] According to other embodiments, the absolute and / or relative position of the UE can be based on the relative position or distance of the UE with respect to certain devices or locations. For example, operations related to direct link communication, such as V2X services, can be activated in a P-UE, for example, when within a certain distance of a road, an intersection, or an RSU, and can be deactivated when the UE is outside a specific distance. The relative distance to one or more other UEs such as V-UEs can be considered. For example, if there are no V-UEs nearby (e.g., determined by direct link measurements), operations associated with direct link communication, such as V2X services, can be deactivated.

[0328] According to other embodiments, a geographical area, such as one or more zones, e.g., based on a zone ID, can be used by a UE to decide to activate / deactivate operations associated with direct link communication, such as V2X services. For example, one or more zones can indicate, or can be defined as, relevant or irrelevant to a V2X service or application. Zones can also distinguish different types of UEs, such as pedestrian UEs, battery-based UEs, bicycle-related UEs, in-vehicle UEs. Depending on the relevance of a zone to a V2X service or application, it can be classified as highly relevant, moderately relevant, low relevant, or irrelevant.

[0329] According to an embodiment, based on any one of the above parameters regarding location / location / distance / area associated with a UE, a V2X service or application can be completely suppressed or stopped from any power-consuming activities, e.g., selecting some or all sensing resources to perform at least transmissions, receptions, and processing related to V2X-related services or applications.

[0330] According to a further embodiment, a V2X application or service can be set up, started, or continued based on a geographical location / distance / area, e.g., when a UE approaches a V2X-related area, such as a road, intersection, or vehicle.

[0331] According to an embodiment, regarding an absolute or relative position, the distance to a traffic scenario can be based on the distance to a roadside unit (RSU) integrated, for example, in a traffic light or traffic sign, or based on the distance to other UEs (e.g., UEs with an activated V2X service or application). To determine the start and stop of a V2X application or service, a threshold can be introduced, especially regarding an absolute or relative position. For example, when approaching an intersection, once a specific distance is determined, e.g., by comparing the distance of a UE (e.g., a battery-based UE) to the intersection with a threshold of x meters, one or more V2X services or applications can be started or continued. On the other hand, when leaving the intersection, the threshold can be used to determine when to turn off or further reduce further power-consuming activities related to the V2X application or service.

[0332] General

[0333] Embodiments of the seventh aspect of the present invention provide a UE that operates in a discontinuous reception (DRX) mode and is configured or pre-configured with a parameter that, in response to a trigger for transmission, extends the default wake-up duration of the DRX cycle according to a sensing window for a sensing process, the sensing window having a size or duration specified by the triggered transmission.

[0334] According to an embodiment, in NR V2X, a V-UE must decode a first-stage SCI to identify any idle or unoccupied time-frequency resources received during a sensing measurement in the most recent past or during a sensing window. The second stage of the two-stage SCI is multiplexed with the Physical Sidelink Shared Channel (PSSCH) and is decoded when the transmission is addressed to a UE by indication of a destination ID or a group ID. For energy-saving UEs with limited power sources, decoding, sensing, receiving data, and transmitting data are the main factors affecting power consumption.

[0335] DRX features support energy-saving UEs to save energy by turning off the RX chain within a network-configured time. However, this may lead to a reduction in the reliability of energy-saving UEs because they may lose sensing information. Therefore, according to an embodiment, the reliability is improved by allowing energy-saving UEs to perform sensing before their transmission. To this end, higher-layer parameters can be defined, such as sensing during the DRX-off time or an extension of the DRX-on duration, to force energy-saving UEs to perform sensing and decoding before transmission. This parameter can be configured by RRC / PC5-RRC signaling, DCI, SCI, or MAC signaling.

[0336] The transition of DRX from an active time to an inactive time may reduce the accuracy of sensing results. According to an embodiment, reliable sensing results while saving energy can be obtained by extending the DRX-on duration. For example, an offset duration can be provided to ensure that the UE can perform or continue sensing within a specified duration. This offset or sensing window time can also be based on QoS and geographical location parameters. The offset duration can be configured by RRC / PC5-RRC, DCI, or SCI.

[0337] According to other embodiments, reliable sensing results while saving energy can be obtained by starting the DRX-on duration earlier than configured. For example, the transition from an active time to an inactive time may cause the loss of sensing results. Therefore, an offset duration is defined to ensure that the UE can start earlier and perform or continue sensing within a specified duration. This offset value or sensing window time can also be based on QoS and geographical location parameters. The offset duration can be configured by RRC / PC5-RRC, DCI, or SCI.

[0338] According to a further embodiment, some V-UEs may send their radio resource RR reservation when other energy-saving UEs are in the sleep mode, i.e., during the DRX off-duration. In this case, the energy-saving UE is not aware of the V-UE RR reservation when transitioning from the sleep mode to the active DRX mode and may thus transmit on the radio resources used by the V-UE for transmission, resulting in a collision. Embodiments of the present invention avoid such collisions by allowing the energy-saving UEs that perform partial or all of the sensing to adjust their sensing window, such as a continuous partial sensing window, and start sensing before the configured active time. This adjustment may be based on additional criteria, such as the QoS or priority associated with the transmission. This prior time period ensures reliable sensing results before the energy-saving user starts transmitting / receiving on the active period.

[0339] Figure 8

[0340] Embodiments of the present invention have been described in detail above, and the corresponding embodiments and aspects may be implemented individually, or two or more embodiments or aspects may be implemented in combination.

[0341] According to an embodiment, a wireless communication system may include a terrestrial network or a non-terrestrial network, or a network or network segment using an airborne vehicle or a spaceborne vehicle as a receiver, or a combination thereof.

[0342] According to an embodiment, the user equipment UE described herein may be one or more of the following: a power-constrained UE; or a handheld UE, such as a UE used by a pedestrian and referred to as a vulnerable road user VRU; or a pedestrian UE, P-UE; or a wearable or handheld UE used by public safety personnel and emergency responders and referred to as a public safety UE, PS-UE; or an IoT UE, e.g., a sensor, an actuator, or a UE provided in a campus network that performs repetitive tasks and requests input from a gateway node at periodic intervals; a mobile terminal; or a stationary terminal; or a cell IoT-UE; or a vehicle UE; or a vehicle group leader GLUE; or a direct link relay; or an IoT or narrowband IoT, NB-IoT, device; or a wearable device, such as a smartwatch, or a fitness tracker, or smart glasses; or a ground-based vehicle; or an aircraft; or an unmanned aerial vehicle; or a base station, such as a gNB; or a mobile base station; or a roadside unit RSU; or a building; or any other item or device provided with network connectivity to enable the item / device to communicate using a wireless communication network, e.g., a sensor or an actuator; or any other item or device provided with network connectivity to enable the item / device to communicate using a direct link of a wireless communication network, e.g., a sensor or an actuator, or a transceiver, or any network entity having direct link capabilities.

[0343] The base station BS described herein can be implemented as a mobile or fixed base station and can be one or more of the following: a macro cell base station, or a small cell base station, or a central unit of a base station, or a distributed unit of a base station, or an integrated access and backhaul IAB node, or a roadside unit RSU, or a UE, or a group leader GL, or a relay or a remote radio head, or an AMF, or an SMF, or a core network entity, or a mobile edge computing MEC entity, or a network slice as in the NR or 5G core context, or any transmit / receive point TRP that enables an article or device to communicate using a wireless communication network, and the article or device is provided with network connectivity to communicate using the wireless communication network.

[0344] Although certain aspects of the concepts have been described in the context of apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of method steps also represent a description of the corresponding block or item or feature of the corresponding apparatus.

[0345] The various elements and features of the present invention can be implemented in hardware using analog and / or digital circuits, in software by executing instructions with one or more general-purpose or special-purpose processors, or as a combination of hardware and software. For example, embodiments of the present invention can be implemented in the environment of a computer system or another processing system. ​ An example of a computer system 600 is shown. The units or modules and the steps of the method executed by these units can be executed on one or more computer systems 600. The computer system 600 includes one or more processors 602, such as a dedicated or general-purpose digital signal processor. The processor 602 is connected to a communication infrastructure 604, such as a bus or a network. The computer system 600 includes a main memory 606, for example, a random access memory RAM, and an auxiliary memory 608, for example, a hard disk drive and / or a removable storage drive. The auxiliary memory 608 can allow a computer program or other instructions to be loaded into the computer system 600. The computer system 600 can further include a communication interface 610 to allow the transfer of software and data between the computer system 600 and external devices. The communication can be from an electronic, electromagnetic, optical, or other signal that can be processed by the communication interface. The communication can use wires or cables, optical fibers, telephone lines, cellular phone links, RF links, and other communication channels 612.

[0346] The terms "computer program medium" and "computer-readable medium" generally refer to tangible storage media such as removable storage units or hard disks installed in hard disk drives. These computer program products are means for providing software to a computer system 600. The computer program, also referred to as computer control logic, is stored in the main memory 606 and / or the auxiliary memory 608. A computer program can also be received via the communication interface 610. The computer program, when executed, causes the computer system 600 to implement the present invention. In particular, when the computer program is executed, it enables the processor 602 to implement the processes of the present invention, such as any of the methods described herein. Thus, such a computer program can represent the controller of the computer system 600. In cases where software is used to implement the disclosure, the software can be stored in a computer program product and loaded into the computer system 600 using a removable storage drive, an interface such as the communication interface 610.

[0347] Implementations in hardware or software can be carried out using digital storage media, such as cloud storage, floppy disks, DVDs, Blu-rays, CDs, ROMs, PROMs, EPROMs, EEPROMs or FLASH memories, on which electronic-readable control signals are stored, which cooperate or are capable of cooperating with a programmable computer system in order to carry out the corresponding methods. Thus, the digital storage media can be computer-readable.

[0348] Some embodiments according to the present invention include a data carrier having an electronically-readable control signal which is capable of cooperating with a programmable computer system so as to carry out one of the methods described herein.

[0349] Generally, embodiments of the present invention can be implemented as a computer program product having program code which is operable, when the computer program product is run on a computer, to carry out one of the methods. For example, the program code can be stored on a machine-readable carrier.

[0350] Other embodiments include a computer program for carrying out one of the methods described herein, the computer program being stored on a machine-readable carrier. In other words, thus, embodiments of the method of the present invention are computer programs having program code for carrying out one of the methods described herein when the computer program is run on a computer.

[0351] Accordingly, a further embodiment of the method of the present invention is a data carrier or digital storage medium, or a computer-readable medium comprising a computer program recorded thereon for performing one of the methods described herein. Accordingly, a further embodiment of the method of the present invention is a data stream or signal sequence representing a computer program for performing one of the methods described herein. For example, the data stream or signal sequence may be configured to be transmitted via a data communication connection, such as via the Internet. Further embodiments include a processing device, such as a computer or a programmable logic device, which is configured or adapted to perform one of the methods described herein. Further embodiments include a computer having installed thereon a computer program for performing one of the methods described herein.

[0352] In some embodiments, a programmable logic device, such as a field programmable gate array, may be used to perform some or all of the functions of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. Generally, the method is preferably performed by any hardware device.

[0353] The above-described embodiments are merely illustrative of the principles of the present invention. It will be understood that modifications and variations to the arrangements and details described herein will be apparent to those skilled in the art. Accordingly, it is intended to be limited only by the scope of the upcoming patent claims, and not by the specific details presented by the description and interpretation of the embodiments herein.

Claims

1. A user equipment (UE) for a wireless communication system, the wireless communication system including a plurality of user equipments (UEs), the UE including: One or more antennas or an antenna array having a plurality of antenna elements, A transceiver, and A signal processor; Wherein, the UE is for communicating with one or more other user equipments (UEs) of the wireless communication network via a direct link, using one or more antennas or the antenna array and the transceiver, Wherein, the signal processor is configured to operate the UE - In a discontinuous reception (DRX) mode, and - In response to a trigger for transmission, perform a sensing process for determining resources to be used for transmission, and Wherein, the UE is for receiving signaling including parameters using one or more antennas or the antenna array and the transceiver, the parameters causing the signal processor to extend a default wake-up duration of a DRX cycle in response to a trigger for transmission, according to a sensing window of the sensing process, the sensing window having a size or duration specified by the triggered transmission.

2. The user equipment (UE) according to claim 1, wherein the default wake-up duration of the DRX cycle includes a default start time and a default end time, and wherein the extension of the default wake-up duration includes one or more of the following to ensure that the UE can perform the sensing process for a specified sensing window size: · An offset of the default end time to a later time; · An offset of the default start time to an earlier time.

3. The user equipment (UE) according to claim 1, wherein the UE is configured or pre-configured with parameters via RRC or PC5-RRC signaling or DCI or SCI or MAC signaling.

4. The user equipment UE according to claim 1, wherein, The UE is configured or pre-configured with a plurality of parameters, each parameter defining a different extension of the wake-up duration, and wherein, the UE is for selecting a parameter to be applied according to one or more predefined criteria.

5. The user equipment (UE) according to claim 4, wherein the one or more predefined criteria include one or more of the following: · One or more quality of service (QoS) requirements associated with the transmission, · One or more transmission parameters, · The priority of the transmission, · The geographical area where the UE is located, · The traffic density, · The user density within a predefined area around the UE, · The type of the UE.

6. The user equipment (UE) according to claim 5, wherein · One or more transmission parameters include a HARQ feedback channel configuration, · The geographical area where the UE is located includes the cell or the minimum communication range (MCR) of the UE, or the relative position or the absolute position of the UE, · The type of the UE includes a vehicular UE or a battery-based UE.

7. The user equipment (UE) according to claim 1, the UE is for: · Communicating with one or more other UEs using a direct link (SL) interface, and / or · Communicating with one or more radio access network (RAN) entities of the wireless communication system using a radio interface, or using a shared access band.

8. The user equipment UE according to claim 1, wherein the UE and / or other UEs include one or more of the following: a power-constrained UE; or a handheld UE; or an IoT UE; or a cellular IoT-UE; or a vehicle UE; or a group leader GL UE; or a direct link relay; or an IoT or narrowband IoT, NB-IoT, device; or a wearable device; or a ground-based vehicle; or an aircraft; or a drone; or a base station; or a mobile base station; or a roadside unit RSU; or a building; or any other item or device provided with network connectivity to enable the item / device to communicate using a wireless communication network; or a transceiver, or any network entity having direct link capabilities.

9. A wireless communication system comprising one or more user equipment UEs according to claim 1.

10. The wireless communication system according to claim 9, comprising one or more base stations, wherein the base station includes one or more of the following: a macro cell base station, or a small cell base station, or a central unit of the base station, or a distributed unit of the base station, or an integrated access and backhaul IAB node, or a roadside unit RSU, or a UE, or a group leader GL, or a relay or a remote radio head, or an AMF, or an SMF, or a core network entity, or a mobile edge computing MEC entity, or a network slice, or any transmission / reception point TRP enabling an item or device to communicate using a wireless communication network, the item or device being provided with network connectivity to communicate using the wireless communication network.

11. A method for operating a user equipment UE of a wireless communication system, the wireless communication system comprising a plurality of user equipment UEs, wherein the UE is configured to communicate with one or more other user equipment UEs of the wireless communication network via a direct link, and wherein the UE is configured to operate in a discontinuous reception DRX mode, the method comprising: performing a sensing process for determining resources to be used for transmission in response to a trigger for transmission, and receiving signaling comprising parameters that cause an extension of a default wake-up duration of a DRX cycle according to a sensing window of the sensing process in response to a trigger for transmission, the sensing window having a size or duration specified by the triggered transmission.

12. A non-transitory computer-readable medium having stored thereon a computer program which, when executed on a computer, performs the method according to claim 11.

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