WO2024159464A1

WO2024159464A1 - Device, method and computer readable medium for sidelink communications

Info

Publication number: WO2024159464A1
Application number: PCT/CN2023/074160
Authority: WO
Inventors: Thomas Haaning Jacobsen; Renato Barbosa ABREU; Nuno Manuel KIILERICH PRATAS; Torsten WILDSCHEK; Claude Arzelier; Takayuki Shimizu; Jianguo Liu; Timo Erkki Lunttila; Yong Liu; Naizheng ZHENG
Original assignee: Nokia Shanghai Bell Co., Ltd; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2023-02-01
Filing date: 2023-02-01
Publication date: 2024-08-08
Also published as: CN120130117A

Abstract

Embodiments of the present disclosure relate to devices, methods, and computer readable media for sidelink communications. A first terminal device generates a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device. The first terminal device updates the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource. In turn, the first terminal device transmits, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.

Description

DEVICE, METHOD AND COMPUTER READABLE MEDIUM FOR SIDELINK COMMUNICATIONS

TECHNICAL FIELD

Implementations of the present disclosure generally relate to the field of telecommunication, and in particular, to devices, methods and computer readable media for sidelink (SL) communications.

BACKGROUND

Certain communication systems enable vehicle to everything (V2X) and device to device (D2D) communications to be performed. V2X communications can be based on communication technologies such as sidelink communication technologies. For this, sidelink resource pools and sidelink channels can be established for vehicles participating in such communications.

In V2X communications, there are two modes of resource allocation. In a first mode (also referred to as NR V2X mode 1 or mode 1 hereinafter) , one terminal device may perform V2X communications with the other terminal device by using resources allocated by a network device. In a second mode (also referred to as NR V2X mode 2 or mode 2 hereinafter) , one terminal device may perform V2X communications with the other terminal device by using resources autonomously selected in a resource pool by the one terminal device.

SUMMARY

In general, example implementations of the present disclosure provide devices, methods and computer readable media for sidelink communications.

In a first aspect, there is provided a first terminal device. The first terminal device comprises at least one processor and at least one memory including computer program codes. The at least one memory and the computer program codes are configured to, with the at least one processor, cause the first terminal device to: generate a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device; update the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource; and transmit, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.

In a second aspect, there is provided a second terminal device. The second terminal device comprises at least one processor and at least one memory including computer program codes. The at least one memory and the computer program codes are configured to, with the at least one processor, cause the second terminal device to: receive from a first terminal device, assistant information about resource selection for a first sidelink transmission from the second terminal device, the assistant information indicating a set of preferred resources or a set of non-preferred resources for the first sidelink transmission; and perform the resource selection based on the assistant information.

In a third aspect, there is provided a second terminal device. The second terminal device comprises at least one processor and at least one memory including computer program codes. The at least one memory and the computer program codes are configured to, with the at least one processor, cause the second terminal device to: transmit, to a first terminal device, a request for assistant information about resource selection for a first sidelink transmission from the second terminal device based on determining at least one of the following: the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold; previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.

In a fourth aspect, there is provided a method implemented at a first terminal device. The method comprises: generating a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device; updating the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource; and transmitting, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.

In a fifth aspect, there is provided a method implemented at a second terminal device. The method comprises: receiving from a first terminal device, assistant information about resource selection for a first sidelink transmission from the second terminal device, the assistant information indicating a set of preferred resources or a set of non-preferred resources for the first sidelink transmission; and performing the resource selection based on the assistant information.

In a sixth aspect, there is provided a method implemented at a second terminal device. The method comprises: transmitting, from the second terminal device to a first terminal device, a request for assistant information about resource selection for a first sidelink transmission from the second terminal device based on determining at least one of the following: the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold; previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.

In a seventh aspect, there is provided an apparatus. The apparatus comprises: means for generating a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device; means for updating the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource; and means for transmitting, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.

In an eighth aspect, there is provided an apparatus. The apparatus comprises: means for receiving, at a second terminal device from a first terminal device, assistant information about resource selection for a first sidelink transmission from the second terminal device, the assistant information indicating a set of preferred resources or a set of non-preferred resources for the first sidelink transmission; and means for performing the resource selection based on the assistant information.

In a ninth aspect, there is provided an apparatus. The apparatus comprises: means for transmitting, from the second terminal device to a first terminal device, a request for assistant information about resource selection for a first sidelink transmission from the second terminal device based on determining at least one of the following: the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold; previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.

In a tenth aspect, there is provided a non-transitory computer readable medium. The non-transitory computer readable medium comprises program instructions for causing an apparatus to perform the method according to any of the fourth to sixth aspects.

It is to be understood that the summary section is not intended to identify key or essential features of implementations of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some implementations of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

Fig. 1 illustrate an example communication network in which implementations of the present disclosure can be implemented, respectively;

Fig. 2 illustrates an example of NR SL resource allocation in mode 2 in accordance with some example embodiments of the present disclosure;

Fig. 3 illustrates a flowchart of an SL mode 2 resource allocation scheme in accordance with some example embodiments of the present disclosure;

Fig. 4 illustrates a flowchart of a method for determining a resource candidate set in accordance with some example embodiments of the present disclosure;

Fig. 5 illustrates an example of a CCA slot in accordance with some example embodiments of the present disclosure;

Fig. 6 illustrates an example of acquisition of Channel Occupancy Time (COT) in accordance with some example embodiments of the present disclosure;

Fig. 7 illustrates an example of a contention window countdown procedure in accordance with some example embodiments of the present disclosure;

Figs. 8 and 9 illustrate an example of allowed gaps for which Type 2 Listen Before Talk (LBT) procedures to be applicable in accordance with some example embodiments of the present disclosure, respectively;

Fig. 10 illustrates an example of an initiating device communicating through sidelink with a plurality of responding devices under respectively acquired COTs using different types of LBT procedures in accordance with some example embodiments of the present disclosure;

Fig. 11 illustrates an example of interlaced Frequency Domain Multiplexing (FDM) scheme for NR-U uplink in accordance with some example embodiments of the present disclosure;

Fig. 12 illustrates an example of Inter-UE Coordination Information MAC CE in accordance with some example embodiments of the present disclosure;

Fig. 13 illustrates an example of Inter-UE Coordination Request MAC CE in accordance with some example embodiments of the present disclosure;

Fig. 14 illustrates an example of in-band emission (IBE) in accordance with some example embodiments of the present disclosure;

Fig. 15 illustrates an example of IBE in accordance with some example embodiments of the present disclosure;

Fig. 16 illustrates an example of a simulation of emission levels of a terminal device transmitting in one interlace;

Fig. 17 illustrates a signaling chart illustrating a process for sidelink communications in accordance with some example embodiments of the present disclosure;

Fig. 18 illustrates a signaling chart illustrating a process for sidelink communications in accordance with other example embodiments of the present disclosure;

Fig. 19 illustrates a flowchart of an example method in accordance with some embodiments of the present disclosure;

Fig. 20 illustrates a flowchart of an example method in accordance with other embodiments of the present disclosure;

Fig. 21 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

Fig. 22 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (for example, firmware) for operation, but the software may not be present when it is not needed for operation.

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

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (for example, remote surgery) , an industrial device and applications (for example, a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

Fig. 1 illustrates a schematic diagram of an example communication network 100 in which implementations of the present disclosure can be implemented. As shown in Fig. 1, the communication network 100 may comprise a first terminal device 110, a second terminal device 120, a third terminal device 130 and a network device 140 which may communicate with each other via respective wireless communication channels.

It is to be understood that the number of devices 110, 120, 130 and 140 in Fig. 1 is given for the purpose of illustration without suggesting any limitations to the present disclosure. The communication network 100 may include any suitable number of devices adapted for implementing implementations of the present disclosure.

In this example, only for ease of discussion, the first terminal device 110 and the second terminal device 120 are illustrated as vehicles which enable V2X communications. It is to be understood that the vehicles are only example implementations of the first terminal device 110, the second terminal device 120 and the third terminal device 130, respectively, without suggesting any limitation as to the scope of the present application. Any other suitable implementations are possible as well.

The communications in the communication networks 100 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , LTE, LTE-Evolution, LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like. Furthermore, the communications may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols.

In some example embodiments, the communications in the communication network 100 may include sidelink communications. In such implementations, the first terminal device 110, the second terminal device 120 and the third terminal device 130 may use sidelink channels to transmit sidelink signaling or information. The sidelink channels may comprise at least one of the following: a Physical Sidelink Control Channel (PSCCH) which is used for carrying sidelink control information (SCI) , a Physical Sidelink Shared Channel (PSSCH) which is used for carrying sidelink data, a physical sidelink feedback channel (PSFCH) which is used for carrying sidelink ACK/NACK feedback information, a physical sidelink broadcast channel (PSBCH) which is used for carrying sidelink broadcast information, and a physical sidelink discovery channel (PSDCH) which is used for carrying a sidelink discovery signal.

NR-SL Overview

NR SL has been designed to facilitate a UE to communicate with other nearby UE (s) via direct/SL communication. Two resource allocation modes have been specified, and a SL transmitter (TX) UE (such as the first terminal device 110) is configured with one of them to perform its NR SL transmissions. These modes are denoted as NR SL mode 1 and NR SL mode 2. In mode 1, a sidelink transmission resource is assigned or scheduled by a network device (such as the network device 140) to the SL TX UE, while a SL TX UE in mode 2 autonomously selects its SL transmission resources.

In mode 1, the network device (such as the network device 140) is responsible for SL resource allocation, the configuration and operation is similar to the one over the Uu interface. The MAC level details of this procedure are given in section 5.8.3 of 3GPP TS 38.321.

Fig. 2 illustrates an example of NR SL resource allocation in mode 2. In mode 2, SL UEs perform autonomously the resource selection with the aid of a sensing procedure. More specifically, a SL TX UE in NR SL mode 2 first performs a sensing procedure over the configured one or more SL transmission resource pools in order to obtain the knowledge of one or more reserved resources by at least one other nearby SL TX UE. Based on the knowledge obtained from sensing, the SL TX UE may select at least one resource from the available SL resources accordingly. In order for a SL UE to perform sensing and obtain the necessary information to receive a SL transmission, it needs to decode the sidelink control information (SCI) . In Release 16, the SCI associated with a data transmission includes a 1st-stage SCI and 2nd-stage SCI, and their contents are standardized in 3GPP TS 38.212.

NR SL resource allocation mode 2

In mode 2 SL, each UE autonomously selects resources by decoding physical sidelink control channel (PSCCH) (or sidelink control information (SCI) ) and performing RSRP measurement of (pre-) configured resource pool (s) based on a procedure specified in 3GPP 38.214 Section 8.1 on a candidate resource pool during a sensing window interval.

Fig. 3 illustrates a flowchart of a legacy SL resource allocation method 300. As shown in Fig. 3, at block 310, UE (for example, the first terminal device 110) has data to transmit and thus the sensing procedure for resource selection is initiated.

At block 320, UE collects sensing information including reserved resources and SL-RSRP measurements.

At block 330, UE forms a candidate resource set.

At block 340, UE selects Tx resources with starting time ‘m’ .

At block 350, UE re-evaluates resource selection by keeping decoding other UEs’ PSCCH and measuring corresponding PSSCH energy.

At block 360, UE determines whether resource re-selection is triggered (from re-evaluation) .

If the resource re-selection is not triggered, UE begins transmission on the selected resources at block 370. If the resource re-selection is triggered, the method 300 proceeds to block 320.

At block 380, UE determines whether resource re-selection is triggered by reaching maximum number of reservations.

If the resource re-selection is triggered by reaching maximum number of reservations, UE restarts the method 300 and method 300 proceeds to block 320. If the resource re-selection is not triggered, UE continues using reservation and the method 300 proceeds to block 370.

In the method 300, regarding the block 310, the monitoring of the resource pool and acquisition of information to be used during the resource selection procedure can be done prior to the Tx UE knowing that it has a transmission to perform. In addition, regarding the block 330, after the Tx UE has acquired enough information from its monitoring of the resource pool it can form the candidate resource set.

Fig. 4 illustrates a flowchart of a method 400 for determining the resource candidate set. A method 400 occurs for resources within a candidate resource pool, which have been monitored during a sensing window interval. During this sensing window interval, UE (for example, the first terminal device 110) collects the set of S_A of potential candidate resource slots that are within a defined selection window period and excludes all resources/slots which meet at least one of the following:

The UE has not monitored them during the sensing period (for example, due to own transmission, other activities including DRX, or partial sensing) ; and

The decoded SCI format 1-A indicates that the candidate slot is reserved and the corresponding measured RSRP is above a pre-configured RSRP_threshold.

Specifically, as shown in Fig. 4, at block 410, UE determines the selection window and set RSRP_threshold.

At block 420, UE initializes a candidate single-slot resource set S_A.

At block 430, UE excludes not-monitored resources from the set S_A.

At block 440, UE excludes resources with RSRP greater than RSRP_threshold from the set S_A.

At block 450, UE determines whether the number of remaining slots is greater than |X.S_A|, where X = 0.2, 0.35, or 0.5, |S_A| represents the initial total number of resources in the set S_A.

If the number of remaining slots is less than |X. S_A|, UE increases, at block 460, the RSRP_threshold by a step (i.e., RSRP_threshold = RSRP_threshold + step, where the step is currently defined to be 3 dB) . Then, the method 400 proceeds to block 420.

If the number of remaining slots is greater than |X. S_A|, UE, at block 470, forwards the potential candidate slots to the higher for final resource selection.

Unlicensed operation background

In sub-7GHz unlicensed bands, the new radio (NR) coexistence with other systems (e.g. IEEE 802.11) may be ensured via an LBT channel access mechanism. According to the channel access mechanism, a user equipment (UE) (for example, the first terminal device 110 or the second terminal device 120) intending to perform an SL communication (such as the SL communication 112 or 122) may need first to successfully complete an LBT check, before being able to initiate the same SL communication. Hereinafter, an LBT procedure may also be referred to as Clear Channel Assessment (CCA) or channel access procedure.

For a UE to pass an LBT check, it must observe the channel as available for a number of consecutive CCA slots. In sub-7GHz, the duration of these slots is 9 μs, as depicted in Fig. 5. Fig. 5 shows that CCA slot may have a duration T_sl = 9 us, where the energy sensing takes place during 4 us. The UE deems the channel as available in a CCA slot if the measured power (i.e. the collected energy during the CCA slot) is below a regulatory specified threshold which may depend on the operating band and geographical region.

In an example, when a UE (e.g., the first terminal device 110) takes a role of an initiating device to initiate a communication with a responding device (for example, the second terminal device 120) , this initiating UE may need to acquire the “right” to access the channel for a certain period of time –as denoted in the regulations as the COT –by applying an “extended” LBT procedure where the channel must be deemed as free for the entire duration of a Contention Window (CW) . This “extended” LBT procedure is commonly known as a Type 1 LBT procedure or LBT Type 1 procedure as specified in TS 37.213. This procedure is illustrated in Fig. 6.

Both of a CW duration and a COT duration in Fig. 6 may depend on the Channel Access Priority Class (CAPC) associated with the UE’s traffic (e.g., p=1 to p=4) , as shown in Table 1. Control plane traffic (such as physical sidelink control channel (PSCCH) ) may be transmitted with a priority of p=1, while user plane traffic has a priority of p>1. Table 1 depicts details of the Type 1 LBT for the Uu uplink (UL) case. It may be noted that in the downlink (DL) case, Type 1 LBT parameters may also in principle be adopted in SL.

Table 1

Table 1 shows CAPC for UL. The contention window length in CCA slots associated with each CAPC has a minimum (CW_min, p) and maximum (CW_max, p) . The duration of the COT is given by T_ulm cot, p.

Examples of behavior during the contention window countdown procedure are depicted in Fig. 7. It should be noted that if during the countdown procedure the LBT check fails in any CCA slot, the countdown procedure will stop and will only resume if the channel is deemed as free (i.e. the LBT check is successful) during a defer time.

In Fig. 7, T_d represents the defer time, T_sl represents the CCA slot duration and N represents the number of CCA slots required to be deemed as free before the contention window countdown is completed. Specifically, Fig. 7 shows a Type 1 LBT contention window countdown procedure and examples on how it can be disrupted. In example (a) , when neither the defer time T_d nor the countdown are disrupted (i.e., the channel is not detected as busy during a sensing slot) . In example (b) , the defer time T_d is disrupted (i.e., the channel is detected as busy during a defer time sensing slot) . In example (c) , the contention window countdown is disrupted (i.e., the channel is detected as busy during a sensing slot of the countdown) .

The UE initiating the transmission (also referred to as the initiating device, e.g., the second terminal device 120) upon successfully completing performing the Type 1 LBT procedure and performing a transmission (e.g., to the first terminal device 110) , may acquire the COT with duration associated with a priority p in the corresponding CAPC. The acquired COT may be valid even in the case where the initiating device may pause its transmission, although if the initiating device wants to perform a new transmission (within the COT) it may still be required to perform a “reduced” LBT procedure. This “reduced” LBT procedure is commonly known as a Type 2 LBT procedure or LBT Type 2 procedure with the following variants:

Type 2A (25 μs LBT) –for SL transmissions within a COT that the initiating device acquires (in case the gap between two SL transmissions is ≥ 25 μs, as well for SL transmissions following another SL transmission) , as depicted in example (c) in Fig. 8 and example (f) in Fig. 9;

Type 2B (16 μs LBT) –for SL transmission within a COT that the initiating device acquires (can only be used for SL transmissions following another SL with a gap exactly equal to 16 μs) , as depicted in example (b) in Fig. 8 and example (e) in Fig. 9;

Type 2C (no LBT) –which can only be used for SL transmission following another SL, with a gap < 16 μs and the allowed duration of the SL transmission ≤ 584 μs, as depicted in example (a) in Fig. 8 and example (d) in Fig. 9.

In addition, the examples (a) , (b) and (c) show the case where the gap is between the two transmissions both from the same initiating UE (for example, the second terminal device 120) , while the examples (d) , (e) , and (f) show the case that the gap is between the two different transmissions from the initiating UE (for example, the second terminal device 120) and the responding UE (for example, the first terminal device 110) , correspondingly.

The initiating device (for example, the second terminal device 120) may share its acquired COT with its intended receiver (also referred to as the responding device (for example, the first terminal device 110) ) . For this purpose, the initiating device shall inform (for example, via control signaling) the responding device about the duration of this COT. The responding device then uses this information to decide which type of LBT procedure it should apply upon performing a transmission for which the intended receiver is the initiating device. In case the responding device transmission falls outside the COT, then the responding device will have to acquire a new COT using the Type 1 LBT with an appropriate class p in the CAPC. This will be described with reference to Fig. 10.

Fig. 10 illustrates an example of an initiating device communicating through sidelink with a plurality of responding devices under respectively acquired COTs using different types of LBT procedures according to an implementation. According to Fig. 10, an initiating device (i.e., UE A) may first acquire a new COT 1005 using a Type 1 LBT procedure 1010. The initiating device (UE A) may then transmit through a sidelink transmission 1015 on PSCCH and/or physical sidelink shared channel (PSSCH) to a first responding device (UE B) . In addition, UE A may share its acquired COT 1005 with UE B. UE B may then use this acquired COT 1005 information to decide which type of LBT procedure it should apply when performing a transmission to UE A as an intended receiver. In practice, UE A may inform (e.g. via control signaling) UE B about a duration of the COT 1005 within the SL transmission 1015. In response, UE B may be configured to perform a Type 2 LBT procedure 1020 and transmit SL feedback information 1025 to UE A, on the PSFCH.

Alternately, UE B may communicate with another responding device (e.g., UE C) . In case a transmission from UE B to UE C falls outside the duration of the COT 1005, UE B may need to acquire a new COT 1030 using the Type 1 LBT procedure 1035 according to an appropriate class p in the CAPC. UE B may then transmit SL transmission 1040 on the PSCCH and/or PSSCH to UE C and share its acquired COT 1030 with UE C. UE C may use the COT 1030 information to decide which type of LBT procedure UE C should apply when performing a transmission to UE B as the intended receiver. In practice, UE B may inform (e.g. via control signaling) UE C about the duration of the COT 1030 within the SL transmission 1040. In response, UE C may be configured to perform a Type 2 LBT procedure 1045 and transmit SL feedback information 1050 to UE B on the PSFCH.

Occupied Channel Bandwidth (OCB) and Power Spectral Density (PSD) requirements

The scope of NR in unlicensed spectrum was limited to below 7 GHz bands. For this frequency range, the following spectrum regulatory requirements for the design of UL physical channels are captured from EU regulations.

ETSI specifies that OCB shall be between 80%and 100%of the declared Nominal Channel Bandwidth.

As per updated ETSI regulation, during a COT, equipment may operate temporarily with an Occupied Channel Bandwidth of less than 80 %of its Nominal Channel Bandwidth with a minimum of 2 MHz.

Regulations on the maximum power spectral density are typically stated with a resolution bandwidth of 1 MHz. The ETSI specification requires a maximum Power Spectral Density (PSD) of 10 dBm/MHz for 5140-5350 MHz. It requires 10 KHz resolution for testing the 1 MHz PSD constraint and, thus, the maximum PSD constraint should be met in any occupied 1 MHz bandwidth.

In addition, the regulations impose a band specific total maximum transmission power in terms of EIRP, for example, ETSI has EIRP limit of 23 dBm for 5140 –5350 MHz.

The regulatory limitations in terms of OCB and PSD guided the design choices for the uplink channels of NR-unlicensed system. The interlaced Frequency Domain Multiplexing (FDM) scheme was adopted. Fig. 11 illustrates an example of interlaced FDM scheme for15 kHz subcarrier spacing (SCS) . In interlaced FDM, specified in TS38.214 as UL resource allocation type 2, the UL resources are allocated in interlaces of 10 equidistant PRBs. The number of interlaces is 10 for 15 kHz SCS and 5 for 30 kHz SCS. For sidelink, one sub-channel equals K interlaces. For example, if sub-channels are configured to be equal to 1 interlace, one sub-channel may contain all the RBs associated to interlace#0. And if sub-channels are configured to be equal to 2 interlaces one sub-channel may comprise all the RBs associated to interlace#0 and interlace#1.

Agreements from 3GPP RAN1 supporting interlace design

During Release 18 in 3GPP RAN1, the PSCCH/PSSCH structure in SL-U has been discussed and the following relevant agreements has been made:

For example, RAN1#109 agreements comprise the following:

For PSCCH and PSSCH in SL-U:

Both R16/R17 NR SL contiguous RB-based and R16 NR-U interlace RB-based transmissions are considered as starting point

RAN1 strives to have unified design for both contiguous RB-based and interlace RB-based transmissions

FFS: whether/how to address IBE (In Band Emission) impact

For PSCCH and PSSCH in SL-U:

For interlace RB-based transmission (if supported) , at least the following candidates can be discussed:

Frequency domain resource allocation granularity is one sub-channel for PSSCH transmission

FFS: Other resource allocation granularity, e.g., RB-level

1 sub-channel equals K interlaces if sub-channel is supported

For example, RAN1#110 agreements comprise the following:

For PSCCH and PSSCH in SL-U:

Both R16/R17 NR SL contiguous RB-based and interlace RB-based transmissions similar to R16 NR-U are supported

FFS details

Other candidates are not precluded

FFS: mapping of PSCCH to frequency resources

FFS: resource indication in time/frequency domain, e.g., how to handle using one RB set or multiple RB sets, etc.

NR sidelink Inter-UE Coordination (IUC)

IUC was introduced in Release 17 and is described as follows in TS 38.300.

The SL UE can support inter-UE coordination (IUC) in Mode 2, whereby a UE-A sends information about resources to UE-B, which UE-B then uses for resource (re) selection. The following schemes of inter-UE coordination are supported:

- IUC Scheme 1, where the coordination information sent from a UE-A to a UE-B is the preferred or non-preferred resources for UE-B's transmission, and

- IUC scheme 2, where the coordination information sent from a UE-A to a UE-B is the presence of expected/potential resource conflict on the resources indicated by UE-B's SCI.

In scheme 1, IUC can be triggered by an explicit request from UE-B, or by a condition at UE-A. UE-A determines the set of resources reserved by other UEs or slots where UE-A, when it is the intended receiver of UE-B, does not expect to perform SL reception from UE-B due to half-duplex operation. UE-A uses these resources as the set of non-preferred resources, or excludes these resources to determine a set of preferred resources and sends the preferred/non-preferred resources to UE-B. UE-B's resources for resource (re) selection can be based on both UE-B's sensing results (if available) and the coordination information received from UE-A, or it can be based only on coordination information received from UE-A. For scheme 1, MAC CE and second-stage SCI or MAC CE only can be used to send IUC. The explicit request and reporting for IUC in unicast manner is supported.

In scheme 2, UE-A determines the expected/potential resource conflict within the resources indicated by UE-B's SCI as either resources reserved by other UEs and identified by UE-A as fully/partially overlapping with the resources indicated by UE-B's SCI, or as slots where UE-A is the intended receiver of UE-B and does not expect to perform SL reception on those slots due to half-duplex operation. UE-B uses the conflicting resources to determine the resources to be reselected and exclude the conflicting resources from the reselected resources. For scheme 2, PSFCH is used to send IUC.

From TS 38.331, it is specified that by configuration the triggering condition for sending a IUC Scheme 1 preferred /non-preferred resource message or an IUC Scheme 1 request message, is either by UE-A implementation or when UE-A has data to transmit.

MAC CEs for IUC Scheme 1 can be found in the CR to TS 38.321 in R2-2203673.

Fig. 12 illustrates an example of Inter-UE Coordination Information MAC CE in accordance with some implementations of the present disclosure. The Inter-UE Coordination Information MAC CE is identified by a MAC subheader with LCID as specified in Table 6.2.4-1 in R2-2203673. The priority of the Inter-UE Coordination Information MAC CE is fixed to '1' . The Inter-UE Coordination Information MAC CE has a variable size with following fields:

- RT: This field indicates the resource set type, i.e., preferred resource set or non-preferred resource set, as the codepoint value of the SCI format 2-C resourceSetType field as specified in TS 38.212.

- RSL: This field indicates the location of reference slot, as the codepoint value of the SCI format 2-C referenceSlotLocation field as specified in TS 38.212. The length of the field is 17 bits. If the length of referenceSlotLocation field in SCI format 2-C as specified in TS 38.212 is shorter than 17 bit, this field contains referenceSlotLocation field using the LSB bits;

- LSI_i: This field indicates lowest subchannel indices for the first resource location of each TRIV, as the codepoint value of the SCI format 2-C lowestIndices field as specified in TS 38.212. LSI₀ indicates lowest subchannel indices for the first resource location of TRIV within the first resource combination, LSI₁ indicates lowest subchannel indices for the first resource location of TRIV within the second resource combination and so on. The length of the field is 5 bits. If the length of lowestIndices field in SCI format 2-C as specified in TS 38.212 is shorter than 5 bit, this field contains lowestIndices field using the LSB bits;

- RC_i: This field indicates resource combination, as the codepoint value of the SCI format 2-C resourceCombination field as specified in TS 38.212. RC₀ indicates the first resource combination, RC₁ indicates the second resource combination and so on. [The maximum number of included resource combination is 8. ] The length of the field is 26 bits. If the length of resourceCombination field in SCI format 2-C as specified in TS 38.212 is shorter than 26 bit, this field contains resourceCombination field using the LSB bits;

- First resource location_i-1: This field indicates first resource location, as the codepoint value of the SCI format 2-C firstResourceLocation field as specified in TS 38.212. First Resource Location₀ indicates the first resource location for the second resource combination, First Resource Location₁ indicates the first resource location for the third resource combination and so on. The length of the field is 13 bits. If the length of firstResourceLocation field in SCI format 2-C as specified in TS 38.212 is shorter than 13 bit, this field contains firstResourceLocation field using the LSB bits;

- R: Reserved bit, set to 0.

Fig. 13 illustrates an example of Inter-UE Coordination Request MAC CE in accordance with some implementations of the present disclosure. The Inter-UE Coordination request MAC CE is identified by a MAC subheader with LCID as specified in Table 6.2.4-1. The priority of the Inter-UE Coordination Request MAC CE is fixed to '1' . The Inter-UE Coordination Request MAC CE has a variable size with following fields:

- RP: This field indicates the resource reservation period, as the codepoint value of the SCI format 2-C resourceReservationPeriod field as specified in TS 38.212. The length of the field is 4 bits. If the length of resourceReservationPeriod field in SCI format 2-C as specified in TS 38.212 is shorter than 4 bit, this field contains resourceReservationPeriod field using the LSB bits;

- Priority: This field indicates the priority, as the codepoint value of the SCI format 2-C priority field as specified in TS 38.212. The length of the field is 3 bits;

- RSWL: This field indicates resource selection window location, as the codepoint value of the SCI format 2-C resourceSelectionWindowLocation field as specified in TS 38.212. The length of the field is 34 bits. If the length of resourceSelectionWindowLocation field in SCI format 2-C as specified in TS 38.212 is shorter than 34 bit, this field contains resourceSelectionWindowLocation field using the LSB bits;

- Number of Subchannel: This field indicates the number of subchannels, as the codepoint value of the SCI format 2-C numberOfSubchannel field as specified in TS 38.212. The length of the field is 5 bits. If the length of numberOfSubchannel field in SCI format 2-C as specified in TS 38.212 is shorter than 5 bit, this field contains numberOfSubchannel field using the LSB bits;

- R: Reserved bit, set to 0.

For Sidelink unlicensed, interlace based PSCCH/PSSCH allocations are to be supported in order to meet the ETSI requirement on occupied channel bandwidth (OCB) . The issue with interlaces is in-band emissions (IBE) will occur from one interlace to nearby interlaces when they are used by different devices due to the imperfect RX filters on a PRB level.

Particularly, the impact of IBE interference is significant when two Tx UEs use nearby interlaces (or right in-between two interlaces where the IQ image will be located) , and where one Tx UE is close to an Rx UE, while the other Tx UE is far from the Rx UE (i.e., near-far problem) .

Fig. 14 illustrates an example of IBE in accordance with some implementations of the present disclosure. As shown in Fig. 14, the terminal device 1410 performs a first transmission to the terminal device 1440, and the terminal device 1420 performs a second transmission to the terminal device 1430. The first transmission and the second transmission are to be performed on a first slot and in a first transmission band. The first transmission band may mean a band where an LBT procedure is performed in unlicensed or shared channels.

In some example embodiments, the first transmission is to be performed on a first interlace in the first transmission band and the second transmission is to be performed on a second interlace in the first transmission band.

The first transmission from the terminal device 1410 may cause IBE to the reception of the second transmission from the terminal device 1420. In other words, the IBE is from a radio resource for the first transmission, or the IBE is to a radio resource for the second transmission. In this regard, the IBE will degrade the reception of the second transmission from the terminal device 1420.

Similarly, the second transmission from the terminal device 1420 may cause IBE to the reception of the first transmission from the terminal device 1410. In this regard, the IBE will degrade the reception of the first transmission from the terminal device 1410.

Fig. 15 shows IBE 1530 from the first transmission 1510 of the terminal device 1410 interferes the reception of the second transmission 1520 from the terminal device 1420.

Fig. 16 shows a simulation (based on model from TS 38.101-1) of the emission levels of a UE transmitting in one interlace. The interlace comprises 10 RBs equally spaced over the 20 MHz band. Total transmit power is equal to 19.5 dBm. A modulation scheme of QPSK is used. Tx frequency is at 5.2GHz.

Fig. 16 highlights the IBE levels of -25dBm/RB and -20dBm/RB on RBs adjacent to transmitting interlace RBs (higher peaks) and on RBs over the IQ image frequencies (lower peaks) , respectively. It is worth nothing that these levels still meet the specification requirements. However, assuming an SL scenario where an aggressor Tx UE (for example, the terminal device 1410 as shown in Fig. 14) is at 1 m distance of a victim Rx UE (for example, the terminal device 1430 as shown in Fig. 14) and a source Tx UE (for example, the terminal device 1420 as shown in Fig. 14) is at 20 m distance, and assuming that both Tx UEs transmit with same power, and path loss difference between aggressor and source Tx UEs is calculated to be ～26 dB (assuming free space) , there is high likelihood of a below 0 dB SINR on the highlighted resources (RBs 31 and 35 as well as other RBs of their interlace) which may translate to a degraded reception on a victim Rx UE receiving a transmission on these resources.

In sidelink unlicenced, a transmitter might not be aware that it is selecting an interlace that will cause an issue for a receiver (for example, due to the hidden node issue) . In general, the hidden (and exposed) node issue is designed to be handled via the IUC framework which was introduced in Release 17, but has not been designed to handle the IBE aspect caused by using interlaces, which are mandated for SL-U by the regulator.

In order to solve the above and other potential problems, embodiments of the present disclosure provide a solution for sidelink communications. In the solution, a first terminal device generates a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device. The first terminal device updates the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource. In turn, the first terminal device transmits, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.

Hereinafter, principle of the present disclosure will be described with reference to Figs. 17 to 22.

Fig. 17 illustrates a signaling chart illustrating a process 1700 for sidelink communications in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the process 1700 will be described with reference to Fig. 1. The process 1700 may involve the first terminal device 110 and the second terminal device 120 in Fig. 1.

As shown in Fig. 17, the first terminal device 110 generates 1710 a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from the second terminal device 120.

The first terminal device 110 updates 1720 the set of non-preferred resources based on IBE from or to a further radio resource.

The first terminal device 110 transmits 1730, to the second terminal device 120, assistant information about resource selection for the first sidelink transmission. The assistant information indicates the set of preferred resources or the set of non-preferred resources.

Upon receiving the assistant information from the first terminal device 110, the second terminal device 120 performs 1740 the resource selection based on the assistant information.

In some example embodiments, the assistant information may comprise IUC information. In such example embodiments, the first terminal device 110 may transmit the assistant information via an IUC message. For example, the IUC message may be an IUC message based on IUC Scheme 1 which is also referred to as an IUC Scheme 1 message.

In some example embodiments, the non-preferred resources may comprise non-preferred resources in frequency domain. The non-preferred resources in frequency domain may comprise non-preferred sub-channels or interlaces.

In some example embodiments, a sub-channel may comprise K interlaces such that indicating a sub-channel maps to specific interlace indices, where K is equal to or larger than one.

Hereinafter, some example embodiments of updating of the set of non-preferred resources will be described.

Updating of the set of non-preferred resources

In some example embodiments, if at least one predetermined condition is met, the first terminal device 110 may update the set of non-preferred resources by adding at least one resource to the set of non-preferred resources.

In some example embodiments, if the first terminal device 110 is a target receiving terminal device of the first sidelink transmission from the second terminal device 120 and the first terminal device 110 will perform a sidelink transmission on a first resource, the first terminal device 110 may add the first resource to the set of non-preferred resources. In such example embodiments, the first resource is also referred to as a half duplex resource, such as a half duplex slot.

In some example embodiments, if the at least one resource is a reserved sub-channel for a second sidelink transmission from the third terminal device 130, the first terminal device 110 may add the at least one resource to the set of non-preferred resources.

In some example embodiments, the at least one resource comprises a reserved sub-channel for the second sidelink transmission from the third terminal device 130. The first terminal device 110 may add, to the set of non-preferred resources, the reserved sub-channel of which at least one interlace is a part .

In such example embodiments, if the first terminal device 110 determines that a Reference Signal Receiving Power (RSRP) estimation performed for the at least one interlace is higher than an RSRP threshold, the first terminal device 110 may determine the number of the at least one interlace based on the RSRP threshold. For example, if the RSRP threshold is equal to 0, the first terminal device 110 may determine the number of the at least one interlace to be X, where X represents an integer greater than 0. If the RSRP threshold is equal to 1, the first terminal device 110 may determine the number of the at least one interlace to be X-1.

In some example embodiments, the at least one resource is adjacent to a reserved resource in frequency domain for the second sidelink transmission from the third terminal device 130.

In such example embodiments, the at least one resource may comprise a first interlace, and the reserved resource may comprise a reserved interlace for the second sidelink transmission from the third terminal device 130. In such example embodiments, each of the at least one resource is also referred to as a nearby interlace.

In some example embodiments, if the first terminal device 110 estimates that degradation in Interference plus Noise Ratio (SINR) on the nearby interlace is above an SINR threshold, the first terminal device 110 may add the nearby interlace to the set of non-preferred resources. For example, if the first terminal device 110 estimates that degradation in SINR on the nearby interlace is not tolerable in terms of estimated Block Error Ratio (BLER) , the first terminal device 110 may add the nearby interlace to the set of non-preferred resources.

In some example embodiments, if the number of Resource Blocks (RBs) between the nearby interlace and the reserved interlace is below a number threshold, the first terminal device 110 may add the nearby interlace to the set of non-preferred resources. In some example embodiments, if the nearby interlace is located in a center of RBs of the reserved interlace, the first terminal device 110 may add the nearby interlace to the set of non-preferred resources.

Such example embodiments may achieve a simple check of which nearby interlaces should be added to the set of non-preferred resources. This may be hardcoded in implementation. The exact distance may be determined based on receiving (RX) characteristics. In one embodiment, in addition to the reserved interlace, also the nearby interlaces are added to the set of non-preferred resources, as well as the interlace that is located in the center of the RBs (i.e., located in the IQ image frequencies) of the reserved interlace. For example, if the reserved interlace occupies RBs #0, 10, 20…, then interlaces occupying RBs #1, 11, 21 …are added to the set of non-preferred resources, interlaces occupying RBs #9, 19, 29 …are added to the set of non-preferred resources, and interlaces occupying RBs #5, 15, 25 …are added to the set of non-preferred resources.

In some example embodiments, if a first priority of the first sidelink transmission from the second terminal device 120 is equal to a predetermined value, the first terminal device 110 may add the nearby interlace to the set of non-preferred resources. For example, only when the priority of the first sidelink transmission from the second terminal device 120 is equal to 1, the first terminal device 110 may add the nearby interlace to the set of non-preferred resources.

In some example embodiments, if a difference between a first physical distance and a second physical distance is above a distance threshold, the first terminal device 110 may add the nearby interlace to the set of non-preferred resources. The first physical distance is between the second terminal device 120 and a target receiver of the first sidelink transmission from the second terminal device 120, the second physical distance is between the third terminal device 130 and the target receiver of the first sidelink transmission. hereinafter, the first physical distance is represented by (d_UE2-UE2Rx) and the second physical distance is represented by (d_UE3-UE2Rx) .

For unicast and/or groupcast transmission, such example embodiments may be used to determine the impact of the near-far problem. For example, the first terminal device 110 considers the reserved resources as non-preferred if |d_UE2-UE2Rx-d_UE3-UE2Rx|> d_threshold, where d_threshold represents the distance threshold. d_threshold may be configured or pre-configured and may be a function of a PRB distance and/or priority of the first sidelink transmission from the second terminal device 120.

In some example embodiments, to estimate the first and second physical distances, for example, the first terminal device 110 may utilize the received V2X messages that include transmission (Tx) UE’s position information (for example, Society of Automotive Engineers (SAE) Basic Safety Messages (BSM) , European Telecommunications Standards Institute (ETSI) Common Awareness Messages (CAM) ) and/or the zone ID and communication range requirement contained in the 2nd SCI Format 2-B (for groupcast with NACK-only HARQ feedback) .

In some example embodiments, the at least one resource to be added to the set of non-preferred resources may comprise a first sub-channel, and the reserved resource for the second sidelink transmission from the third terminal device 130 may comprise a reserved sub-channel. In such example embodiments, the first terminal device 110 may determine whether to add the first sub-channel to the set of non-preferred resources by taking the reserved sub-channel, priorities and a mapping table of a distance threshold and the priorities into account.

In such example embodiments, the first terminal device 110 may determine a priority difference between a first priority of the first sidelink transmission from the second terminal device 120 and a second priority of the second sidelink transmission from the third terminal device 130. The first terminal device 110 may also determine a distance threshold in frequency domain based on the priority difference. If the first terminal device 110 determines that a distance in frequency domain between the first sub-channel and the reserved sub-channel is below the distance threshold, the first terminal device 110 may add the first sub-channel to the set of non-preferred resources.

In such example embodiments, the distance threshold may be in PRB granularity. For example, if the priority difference is equal to 0, the first terminal device 110 may determine the distance threshold to be 10 PRBs. In turn, the first terminal device 110 may add all sub-channels within a distance of 10 PRBs from an edge of the reserved sub-channel. If the priority difference is equal to 1, the first terminal device 110 may determine the distance threshold to be 6 PRBs. In turn, the first terminal device 110 may add all sub-channels within a distance of 6 PRBs from an edge of the reserved sub-channel.

Alternatively, in such example embodiments, the distance threshold may be in sub-channel or interlace granularity.

In some example embodiments, the set of preferred resources is a set of candidate resources where the non-preferred resources are excluded. The set of candidate resources is used for the first sidelink transmission from the second terminal device 120.

In some example embodiments, the first terminal device 110 generates the set of preferred resources by considering the existing allocations and their interlaces and by excluding the non-preferred resources from the set of candidate resources. In some example embodiments, the existing allocations may comprise at least one of the following: a detected reservation from the third terminal device 130 (reserving a resource for a periodic transmission or retransmission) , or resources selected by the first terminal device 110 (but first terminal device 110 has not yet transmitted the initial transmission) .

In some example embodiments, the set of non-preferred resources can be updated as described above.

Alternatively, in some example embodiments, the set of non-preferred resources can also be updated as a variant of the embodiments as described above, where the first terminal device 110 may use other thresholds because the first terminal device 110 is now recommending resources rather than protecting them.

In some example embodiments, the first terminal device 110 may determine, based on the IBE, Reference Signal Receiving Power (RSRP) estimations for the preferred resources. In turn, the first terminal device 110 may include the RSRP estimations in the assistant information. In other words, each of the preferred resources (i.e., recommended resources) is accompanied with a receiver RSRP estimation. In this way, when the second terminal device 120 decides to use a preferred resource, the second terminal device 120 may take into account the impact of IBE.

In some example embodiments, the first terminal device 110 may determine, based on the IBE, a power reduction factor for each of the preferred resources. In turn, the first terminal device 110 may include the power reduction factor in the assistant information. For example, the power reduction factor may be a recommended power backoff parameter. The second terminal device 120 may use the recommended power backoff parameter to adjust its transmission power relative to the latest earlier transmission. For example, the second terminal device 120 may use the recommended power backoff parameter to tune down its transmission power by X dB or a factor of X dB per sub-channel.

In some example embodiments, the first terminal device 110 may determine a duration of a cyclic prefix (CP) signal which is to be transmitted before the first sidelink transmission. In turn, the first terminal device 110 may include the duration of the CP signal in the assistant information. In such example embodiments, the first terminal device 110 may recommend the use of the CP signal if the preferred resource is to be used. This will increase the chance of acquiring channel access in a given slot and block transmissions which may cause IBE.

In some example embodiments, the generation of the set of preferred resources or the set of non-preferred resources may be triggered by the first terminal device 110 or the second terminal device 120. Hereinafter, some example embodiments of triggers for the generation of the set of preferred resources or the set of non-preferred resources will be described.

The first terminal device 110 triggers the generation of the set of non-preferred resources

In some example embodiments, if the first terminal device 110 determines that the IBE will degrade a reception of the first sidelink transmission from the second terminal device 120 or a reception of the second sidelink transmission from the third terminal device 130, the first terminal device 110 may generate the set of preferred resources or the set of non-preferred resources. In other words, if the first terminal device 110 determines that two allocations from the second terminal device 120 and the third terminal device 130 are impacting each other by the IBE, the first terminal device 110 may generate the set of preferred resources or the set of non-preferred resources.

In some example embodiments, when the first terminal device 110 wants to protect an allocation from the second terminal device 120 towards transmissions from the third terminal device 130, the first terminal device 110 may generate the set of preferred resources or the set of non-preferred resources.

In such example embodiments, the first terminal device 110 may generate the set of preferred resources or the set of non-preferred resources based on a priority of a resource allocation. If a first priority of the first sidelink transmission from the second terminal device 120 is higher than a priority threshold, the first terminal device 110 may trigger to generate the non-preferred resource set to protect the allocation from impact of IBE from nearby allocations on nearby interlaces.

In some example embodiments, in the context of unlicensed spectrum, generation of IUC information is triggered by an event.

In some example embodiments, if a Channel Busy Rate (CBR) measured at the second terminal device 120 is above a CBR threshold, the first terminal device 110 may generate the set of non-preferred resources.

In some example embodiments, if the number of failures of Listen Before Talk (LBT) procedures experienced by the first terminal device 110 during an observation interval is above a number threshold, the first terminal device 110 may generate the set of non-preferred resources.

In some example embodiments, if resource reservations indicated by the second terminal device 120 are detected not to contain any transmission from the second terminal device 120 or the third terminal device 130, the first terminal device 110 may generate the set of non-preferred resources. In other words, taking into account the case where another SL UE preempts the second terminal device 120 or transmission did not happen due to LBT failure, the first terminal device 110 may generate the set of non-preferred resources.

In some example embodiments, if the first terminal device 110 has been experiencing interference related to the IBE when monitoring transmissions in a sidelink resource pool, the first terminal device 110 may generate the set of non-preferred resources.

In some example embodiments, if there is IBE observed in adjacent interlaces for sidelink transmissions, the first terminal device 110 may generate the set of non-preferred resources. For example, if the first terminal device 110 has identified during the resource pool monitoring that in specific transmissions there is a significant IBE observed in the adjacent interlaces, the first terminal device 110 may generate the set of non-preferred resources.

In some example embodiments, if the third terminal device 130 which is performing a third sidelink transmission is adjacent to the first terminal device 110, the first terminal device 110 may generate the set of non-preferred resources. In such example embodiments, if the first terminal device 110 has identified, during the resource pool monitoring, resource reservations by other terminal devices (potential source of IBE interference) located next to the first terminal device 110, the first terminal device 110 may generate the set of non-preferred resources. For example, the first terminal device 110 may determine whether the third terminal device 130 close by, by having received a transmission from the third terminal device 130 which includes location data (e.g. via a CAM message or a zone ID in a format 2b SCI) .

The first terminal device 110 triggers the generation of the set of preferred resources

In some example embodiments, if the first terminal device 110 determines that the second terminal device 120 or the third terminal device 130 would benefit from having a coordinated set of resources, the first terminal device 110 may trigger the generation of the set of preferred resources.

In some example embodiments, the first terminal device 110 is already aware of all resources needed for the second terminal device 120 and then signals the set of preferred resources to the second terminal device 120.

In some example embodiments, if the first terminal device 110 has data to transmit, the first terminal device 110 may trigger the generation of the set of preferred resources.

The second terminal device 120 triggers the generation of the set of preferred resources or the set of non-preferred resources

In some example embodiments, the generation of the set of preferred resources or the set of non-preferred resources may be triggered by the second terminal device 120. In such example embodiments, the first terminal device 110 may generate the set of preferred resources or the set of non-preferred resources based on receiving a request for the assistant information from the second terminal device 120.

In example embodiments where the assistant information comprises IUC information, the second terminal device 120 may transmit the request for the assistant information via an IUC request. For example, the IUC request may be an IUC request based on IUC Scheme 1 which is also referred to as an IUC Scheme 1 request.

In some example embodiments, if the number of failures of LBT procedures experienced by the second terminal device 120 is above a number threshold, the second terminal device 120 may transmit the request for the assistant information to the first terminal device 110.

In some example embodiments, if previous transmissions to the first terminal device 110 have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed, the second terminal device 120 may transmit the request for the assistant information to the first terminal device 110.

In some example embodiments, if a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device 110, the second terminal device 120 may transmit the request for the assistant information to the first terminal device 110. For example, if the second terminal device 120 has identified, during the resource pool monitoring, resource reservations by other terminal devices located next to the first terminal device 110, the second terminal device 120 may transmit the request for the assistant information to the first terminal device 110. For example, the second terminal device 120 may identify the resource reservations by other terminal devices located next to the first terminal device 110 based on location information from other terminal devices and the first terminal device 110 or based on the zone ID.

In some example embodiments, if the second terminal device 120 has data to transmit, the second terminal device 120 may transmit the request for the assistant information to the first terminal device 110.

Fig. 18 illustrates a signaling chart illustrating a process 1800 for sidelink communications in accordance with some example embodiments of the present disclosure. The process 1800 may be considered as an example implementation of the process 1700. For the purpose of discussion, the process 1800 will be described with reference to Fig. 1. The process 1800 may involve the first terminal device 110 and the second terminal device 120 in Fig. 1.

As shown in Fig. 18, the first terminal device 110 checks 1811 for a trigger for sending IUC Scheme 1 message. For example, the first terminal device 110 may check whether there is PSSCH allocation from the first terminal device 110.

The first terminal device 110 checks 1812 for a trigger for sending IUC Scheme 1 request. For example, the first terminal device 110 may check whether the first terminal device 110 has data to transmit.

The first terminal device 110 decides 1813 if there is a need for non-preferred resources based on IUC Scheme 1 or preferred resources based on IUC Scheme 1. Hereinafter, non-preferred resources based on IUC Scheme 1 are also referred to as IUC Scheme 1 non-preferred resources, and preferred resources based on IUC Scheme 1 are also referred to as IUC Scheme 1 preferred resources.

In some example embodiments, actions 1814 to 1816 may be performed for IUC Scheme 1 non-preferred resources.

The first terminal device 110 determines 1814 a set of non-preferred resources by sensing results.

The first terminal device 110 adds 1815 adjacent interlaces (i.e., neighbor interlaces) to the set of non-preferred resources if they satisfy at least one predetermined condition.

In turn, the first terminal device 110 transmits 1816, to the second terminal device 120, IUC information indicating IUC Scheme 1 non-preferred resources (which may comprise non-preferred sub-channels (or interlaces) in RB-Sets, accounting for IBE between interlaces.

In some example embodiments, actions 1817 to 1821 may be performed for IUC Scheme 1 preferred resources.

The first terminal device 110 determines 1817 a set of non-preferred resources accounting for IBE.

The first terminal device 110 generates 1818 a set of candidate resources.

The first terminal device 110 excludes 1819 non-preferred resources from the candidate resources to form a set of preferred resources.

The first terminal device 110 adds 1820 RSRP estimation to each of the preferred resources.

The first terminal device 110 transmits 1821, to the second terminal device 120, IUC information indicating IUC scheme 1 preferred resources where non-preferred sub-channels (or interlaces) in RB-Sets are excluded by accounting for IBE and adding an RSRP estimation to each preferred resource to account for IBE.

Upon receiving the IUC information, the second terminal device 120 performs 1822 resource selection based on the IUC information.

In some example embodiments, the at least one condition used to determine which interlaces are to be considered as non-preferred may be signalled on-beforehand to the recipient terminal device. The recipient terminal device may be the first terminal device 110 or the second terminal device 120.

For example, the at least one condition to be used to determine non-preferred resources may be in the pre-configuration. In another example, the at least one condition to be used to determine non-preferred resources may be defined by the initiating UE via RRC. This would mean, for example, that the first terminal device 110 could tell the second terminal device 120 or the third terminal device 130 that it will consider sub-channels located within W RBs to an allocated sub-channel as non-preferred.

In some example embodiments, there is an alternative indication of interlaces and saving of signalling overhead. If a sub-channel is defined as consisting of more than one interlace, and an allocation can be done on a subset of these interlaces, then an additional field in the SCI and/or the MAC CE is needed to indicate the related interlace. That would, however, cause quite some overhead. For example, if 10 interlaces are defined per sub-channel, then an additional 5bits is needed per sub-channel. To counter that, the first terminal device 110 will only include interlace indications when needed.

One condition for such need may be the channel utilization, i.e., do not include interlace information when the channel is not utilized (measured via CBR) above a certain threshold.

Another condition is to only include interlace information when interlaced PSSCH and PSCCH is enabled in the selected resource pool.

A third condition is to only include interlace information on a sub-channel when there is a non-preferred interlace.

Fig. 19 illustrates a flowchart of an example method 1900 in accordance with some implementations of the present disclosure. In some example embodiments, the method 1900 can be implemented at a terminal device, such as the first terminal device 110, the second terminal device 120 or the third terminal device 130 as shown in Fig. 1. For the purpose of discussion, the method 1900 will be described with reference to Fig. 1 as performed by the first terminal device 110 without loss of generality.

At block 1910, the first terminal device 110 generates a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from the second terminal device 120.

At block 1920, the first terminal device 110 updates the set of non-preferred resources based on IBE from or to a further radio resource.

At block 1930, the first terminal device 110 transmits, to the second terminal device 120, assistant information about resource selection for the first sidelink transmission. The assistant information indicates the set of preferred resources or the set of non-preferred resources.

In some example embodiments, updating the set of non-preferred resources comprises: based on determining that at least one predetermined condition is met, adding at least one resource to the set of non-preferred resources.

In some example embodiments, the at least one resource is adjacent to a reserved resource in frequency domain for a second sidelink transmission from a third terminal device.

In some example embodiments, the at least one resource comprises a first interlace, and the reserved resource comprises a reserved interlace. Adding the first interlace comprises: adding the first interlace to the set of non-preferred resources based on determining at least one of the following: degradation in Interference plus Noise Ratio (SINR) on the first interlace is above an SINR threshold, the number of Resource Blocks (RBs) between the first interlace and the reserved interlace is below a number threshold, the first interlace is located in a center of RBs of the reserved interlace, a first priority of the first sidelink transmission is equal to a predetermined value, or a difference between a first physical distance and a second physical distance is above a distance threshold, wherein the first physical distance is between the second terminal device and a target receiver of the first sidelink transmission, the second physical distance is between the third terminal device and the target receiver.

In some example embodiments, the at least one resource comprises a reserved sub-channel for a second sidelink transmission from a third terminal device. Updating the set of non-preferred resources comprises: adding the reserved sub-channel to the set of non-preferred resources, wherein at least one interlace is part of the reserved sub-channel.

In some example embodiments, the method further comprises: based on determining that a Reference Signal Receiving Power (RSRP) estimation performed for the at least one interlace is higher than an RSRP threshold, determining the number of the at least one interlace based on the RSRP threshold.

In some example embodiments, the at least one resource comprises a first sub-channel, and the reserved resource comprises a reserved sub-channel for a second sidelink transmission from a third terminal device. Adding the first resource to the set of non-preferred resources comprises: determining a priority difference between a first priority of the first sidelink transmission and a second priority of the second sidelink transmission; determining a distance threshold in frequency domain based on the priority difference; and based on determining that a distance in frequency domain between the first sub-channel and the reserved sub-channel is below the distance threshold, adding the first sub-channel to the set of non-preferred resources.

In some example embodiments, the set of preferred resources is a set of candidate resources where the non-preferred resources are excluded, the set of candidate resources being used for the first sidelink transmission from the second terminal device.

In some example embodiments, the method further comprises: determining, based on the IBE, Reference Signal Receiving Power (RSRP) estimations for the preferred resources; and including the RSRP estimations in the assistant information.

In some example embodiments, the method further comprises: determining a duration of a cyclic prefix (CP) signal which is to be transmitted before the first sidelink transmission; and including the duration of the CP signal in the assistant information.

In some example embodiments, the generation of the set of preferred resources or the set of non-preferred resources is triggered by the first terminal device.

In some example embodiments, generating the set of non-preferred resources comprises generating the set of non-preferred resources based on determining at least one of the following: the IBE will degrade a reception of the first sidelink transmission or a reception of the second sidelink transmission; a first priority of the first sidelink transmission is higher than a priority threshold; a Channel Busy Rate (CBR) measured at the second terminal device is above a CBR threshold; the number of failures of Listen Before Talk (LBT) procedures experienced by the first terminal device during an observation interval is above a number threshold; resource reservations indicated by the second terminal device are detected not to contain any transmission from the second terminal device or the third terminal device; the first terminal device has been experiencing interference related to the IBE when monitoring transmissions in a sidelink resource pool; there is IBE observed in adjacent interlaces for sidelink transmissions; or the third terminal device which is performing a third sidelink transmission is adjacent to the first terminal device.

In some example embodiments, generating the set of preferred resources or the set of non-preferred resources comprises: generating the set of preferred resources or the set of non-preferred resources based on receiving a request for the assistant information from the second terminal device.

Fig. 20 illustrates a flowchart of an example method 2000 in accordance with some implementations of the present disclosure. In some example embodiments, the method 2000 can be implemented at a terminal device, such as the first terminal device 110, the second terminal device 120 or the third terminal device 130 as shown in Fig. 1. For the purpose of discussion, the method 2000 will be described with reference to Fig. 1 as performed by the second terminal device 120 without loss of generality.

At block 2010, the second terminal device 120 receives from the first terminal device 110, assistant information about resource selection for a first sidelink transmission from the second terminal device 120. The assistant information indicates a set of preferred resources or a set of non-preferred resources for the first sidelink transmission.

At block 2020, the second terminal device 120 performs the resource selection based on the assistant information.

In some example embodiments, the method further comprises: transmitting, to the first terminal device, a request for the assistant information based on determining at least one of the following: the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold; previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.

In some example implementations, an apparatus capable of performing any of the method 1900 (for example, the first terminal device 110) may comprise means for performing the respective steps of the method 1900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example implementations, the apparatus comprises: means for generating a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device; means for updating the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource; and means for transmitting, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.

In some example embodiments, the means for updating the set of non-preferred resources comprises: based on determining that at least one predetermined condition is met, means for adding at least one resource to the set of non-preferred resources.

In some example embodiments, the at least one resource comprises a first interlace, and the reserved resource comprises a reserved interlace. The means for adding the first interlace comprises: means for adding the first interlace to the set of non-preferred resources based on determining at least one of the following: degradation in Interference plus Noise Ratio (SINR) on the first interlace is above an SINR threshold, the number of Resource Blocks (RBs) between the first interlace and the reserved interlace is below a number threshold, the first interlace is located in a center of RBs of the reserved interlace, a first priority of the first sidelink transmission is equal to a predetermined value, or a difference between a first physical distance and a second physical distance is above a distance threshold, wherein the first physical distance is between the second terminal device and a target receiver of the first sidelink transmission, the second physical distance is between the third terminal device and the target receiver.

In some example embodiments, the at least one resource comprises a reserved sub-channel for a second sidelink transmission from a third terminal device. The means for updating the set of non-preferred resources comprises: means for adding the reserved sub-channel to the set of non-preferred resources, wherein at least one interlace is part of the reserved sub-channel.

In some example embodiments, the apparatus further comprises: based on determining that a Reference Signal Receiving Power (RSRP) estimation performed for the at least one interlace is higher than an RSRP threshold, means for determining the number of the at least one interlace based on the RSRP threshold.

In some example embodiments, the at least one resource comprises a first sub-channel, and the reserved resource comprises a reserved sub-channel for a second sidelink transmission from a third terminal device. The means for adding the first resource to the set of non-preferred resources comprises: means for determining a priority difference between a first priority of the first sidelink transmission and a second priority of the second sidelink transmission; means for determining a distance threshold in frequency domain based on the priority difference; and based on determining that a distance in frequency domain between the first sub-channel and the reserved sub-channel is below the distance threshold, means for adding the first sub-channel to the set of non-preferred resources.

In some example embodiments, the apparatus further comprises: means for determining, based on the IBE, Reference Signal Receiving Power (RSRP) estimations for the preferred resources; and including the RSRP estimations in the assistant information.

In some example embodiments, the apparatus further comprises: means for determining a duration of a cyclic prefix (CP) signal which is to be transmitted before the first sidelink transmission; and means for including the duration of the CP signal in the assistant information.

In some example embodiments, the means for generating the set of non-preferred resources comprises means for generating the set of non-preferred resources based on determining at least one of the following: the IBE will degrade a reception of the first sidelink transmission or a reception of the second sidelink transmission; a first priority of the first sidelink transmission is higher than a priority threshold; a Channel Busy Rate (CBR) measured at the second terminal device is above a CBR threshold; the number of failures of Listen Before Talk (LBT) procedures experienced by the first terminal device during an observation interval is above a number threshold; resource reservations indicated by the second terminal device are detected not to contain any transmission from the second terminal device or the third terminal device; the first terminal device has been experiencing interference related to the IBE when monitoring transmissions in a sidelink resource pool; there is IBE observed in adjacent interlaces for sidelink transmissions; or the third terminal device which is performing a third sidelink transmission is adjacent to the first terminal device.

In some example embodiments, the means for generating the set of preferred resources or the set of non-preferred resources comprises: means for generating the set of preferred resources or the set of non-preferred resources based on receiving a request for the assistant information from the second terminal device.

In some example implementations, an apparatus capable of performing any of the method 2000 (for example, the first terminal device 110) may comprise means for performing the respective steps of the method 2000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example implementations, the apparatus comprises: means for receiving, at a second terminal device from a first terminal device, assistant information about resource selection for a first sidelink transmission from the second terminal device, the assistant information indicating a set of preferred resources or a set of non-preferred resources for the first sidelink transmission; and means for performing the resource selection based on the assistant information.

In some example implementations, the apparatus further comprises: means for transmitting, to the first terminal device, a request for the assistant information based on determining at least one of the following: the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold; previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.

Fig. 21 is a simplified block diagram of a device 2100 that is suitable for implementing example embodiments of the present disclosure. The device 2100 may be provided to implement a communication device, for example, the first terminal device 110 or the second terminal device 120 as shown in Fig. 1. As shown, the device 2100 includes one or more processors 2110, one or more memories 2120 coupled to the processor 2110, and one or more communication modules 2140 coupled to the processor 2110.

The communication module 2140 is for bidirectional communications. The communication module 2140 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 2140 may include at least one antenna.

The processor 2110 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 2100 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 2120 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 2124, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , an optical disk, a laser disk, and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 2122 and other volatile memories that will not last in the power-down duration.

A computer program 2130 includes computer executable instructions that could be executed by the associated processor 2110. The program 2130 may be stored in the memory, e.g., ROM 2124. The processor 2110 may perform any suitable actions and processing by loading the program 2130 into the RAM 2122.

The example embodiments of the present disclosure may be implemented by means of the program 2130 so that the device 2100 may perform any process of the disclosure as discussed with reference to Figs. 1 to 20. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some example embodiments, the program 2130 may be tangibly contained in a computer readable medium which may be included in the device 2100 (such as in the memory 2120) or other storage devices that are accessible by the device 2100. The device 2100 may load the program 2130 from the computer readable medium to the RAM 2122 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 22 shows an example of the computer readable medium 2200 which may be in form of CD, DVD or other optical storage disk. The computer readable medium has the program 2130 stored thereon.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above with reference to Figs. 1 to 20. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

It should be appreciated that though some embodiments may be implemented by/at IAB nodes, solutions including methods and apparatus proposed in this disclosure could also be applied in other communication systems where similar technical problems exist. Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A first terminal device, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first terminal device to:

generate a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device;

update the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource; and

transmit, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.
The first terminal device of claim 1, wherein the first terminal device is caused to update the set of non-preferred resources by:

based on determining that at least one predetermined condition is met, adding at least one resource to the set of non-preferred resources.
The first terminal device of claim 2, wherein the at least one resource is adjacent to a reserved resource in frequency domain for a second sidelink transmission from a third terminal device.
The first terminal device of claim 3, wherein the at least one resource comprises a first interlace, and the reserved resource comprises a reserved interlace; and

the first terminal device is caused to add the first interlace to the set of non-preferred resources based on determining at least one of the following:

degradation in Interference plus Noise Ratio (SINR) on the first interlace is above an SINR threshold,

the number of Resource Blocks (RBs) between the first interlace and the reserved interlace is below a number threshold,

the first interlace is located in a center of RBs of the reserved interlace,

a first priority of the first sidelink transmission is equal to a predetermined value, or

a difference between a first physical distance and a second physical distance is above a distance threshold, wherein the first physical distance is between the second terminal device and a target receiver of the first sidelink transmission, the second physical distance is between the third terminal device and the target receiver.
The first terminal device of claim 2, wherein the at least one resource comprises a reserved sub-channel for a second sidelink transmission from a third terminal device; and

the first terminal device is caused to update the set of non-preferred resources by:

adding the reserved sub-channel to the set of non-preferred resources, wherein at least one interlace is part of the reserved sub-channel.
The first terminal device of claim 5, wherein the first terminal device is further caused to:

based on determining that a Reference Signal Receiving Power (RSRP) estimation performed for the at least one interlace is higher than an RSRP threshold, determine the number of the at least one interlace based on the RSRP threshold.
The first terminal device of claim 3, wherein the at least one resource comprises a first sub-channel, and the reserved resource comprises a reserved sub-channel for a second sidelink transmission from a third terminal device; and

the first terminal device is caused to add the first resource to the set of non-preferred resources by:

determining a priority difference between a first priority of the first sidelink transmission and a second priority of the second sidelink transmission; and

determining a distance threshold in frequency domain based on the priority difference;

based on determining that a distance in frequency domain between the first sub-channel and the reserved sub-channel is below the distance threshold, adding the first sub-channel to the set of non-preferred resources.
The first terminal device of claim 1, wherein the set of preferred resources is a set of candidate resources where the non-preferred resources are excluded, the set of candidate resources being used for the first sidelink transmission from the second terminal device.
The first terminal device of claim 8, wherein the first terminal device is further caused to:

determine, based on the IBE, Reference Signal Receiving Power (RSRP) estimations for the preferred resources; and

include the RSRP estimations in the assistant information.
The first device of claim 8, wherein the first terminal device is further caused to:

determine a duration of a cyclic prefix (CP) signal which is to be transmitted before the first sidelink transmission; and

include the duration of the CP signal in the assistant information.
The first terminal device of claim 1, wherein the generation of the set of preferred resources or the set of non-preferred resources is triggered by the first terminal device.
The first terminal device of claim 11, wherein the first terminal device is caused to generate the set of non-preferred resources based on determining at least one of the following:

the IBE will degrade a reception of the first sidelink transmission or a reception of the second sidelink transmission;

a first priority of the first sidelink transmission is higher than a priority threshold;

a Channel Busy Rate (CBR) measured at the second terminal device is above a CBR threshold;

the number of failures of Listen Before Talk (LBT) procedures experienced by the first terminal device during an observation interval is above a number threshold;

resource reservations indicated by the second terminal device are detected not to contain any transmission from the second terminal device or the third terminal device;

the first terminal device has been experiencing interference related to the IBE when monitoring transmissions in a sidelink resource pool;

there is IBE observed in adjacent interlaces for sidelink transmissions; or

the third terminal device which is performing a third sidelink transmission is adjacent to the first terminal device.
The first terminal device of claim 1, wherein the first terminal device is caused to generate the set of preferred resources or the set of non-preferred resources based on receiving a request for the assistant information from the second terminal device.
A second terminal device, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second terminal device to:

receive from a first terminal device, assistant information about resource selection for a first sidelink transmission from the second terminal device, the assistant information indicating a set of preferred resources or a set of non-preferred resources for the first sidelink transmission; and

perform the resource selection based on the assistant information.
The second terminal device of claim 14, wherein the second terminal device is further caused to:

transmit, to the first terminal device, a request for the assistant information based on determining at least one of the following:

the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold

previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or

a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.
A second terminal device, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second terminal device to:

transmit, to a first terminal device, a request for assistant information about resource selection for a first sidelink transmission from the second terminal device based on determining at least one of the following:

the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold

previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or

a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.
A method, comprising:

generating, at a first terminal device, a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device;

updating the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource; and

transmitting, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.
A method, comprising:

receiving, at a second terminal device from a first terminal device, assistant information about resource selection for a first sidelink transmission from the second terminal device, the assistant information indicating a set of preferred resources or a set of non-preferred resources for the first sidelink transmission; and

performing the resource selection based on the assistant information.
A method, comprising:

transmitting, from a second terminal device to a first terminal device, a request for assistant information about resource selection for a first sidelink transmission from the second terminal device based on determining at least one of the following:

the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold

previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or

a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.
An apparatus, comprising:

means for generating, at a first terminal device, a set of non-preferred resources or a set of preferred resources for a first sidelink transmission from a second terminal device;

means for updating the set of non-preferred resources based on in-band emission (IBE) from or to a further radio resource; and

means for transmitting, to the second terminal device, assistant information about resource selection for the first sidelink transmission, the assistant information indicating the set of preferred resources or the set of non-preferred resources.
An apparatus, comprising:

means for receiving, at a second terminal device from a first terminal device, assistant information about resource selection for a first sidelink transmission from the second terminal device, the assistant information indicating a set of preferred resources or a set of non-preferred resources for the first sidelink transmission; and

means for performing the resource selection based on the assistant information.
An apparatus, comprising:

means for transmitting, from a second terminal device to a first terminal device, a request for assistant information about resource selection for a first sidelink transmission from the second terminal device based on determining at least one of the following:

the number of failures of Listen Before Talk (LBT) procedures experienced by the second terminal device is above a number threshold

previous transmissions to the first terminal device have occurred on a first plurality of resources adjacent to a second plurality of resources reserved by at least one third terminal device and the previous transmissions have failed; or

a third plurality of resources reserved by at least one fourth terminal device are adjacent to a fourth plurality of resources reserved by the first terminal device.