WO2023050326A1

WO2023050326A1 - Inter-ue coordination for sl resource allocation

Info

Publication number: WO2023050326A1
Application number: PCT/CN2021/122211
Authority: WO
Inventors: Tao Chen
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2023-04-06
Also published as: CN115915063A

Abstract

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus about inter-UE coordination for SL enhancement. The UE can request the other UE (s) to provide the information about the preferred resources for transmission. Such request can be realized by PSFCH based physical channel, 1st SCI and/or 2nd SCI based SL control information, and/or MAC-CE based physical data channel. The container for the request can be selected depending on the contents of the request and QoS requirement (latency, congestion control, etc). The request can sent via the (pre-) configured resources. Moreover, the resource for the request transmission can be SL pair specific, e.g., derived based on the both UEs' IDs.

Description

INTER-UE COORDINATION FOR SL RESOURCE ALLOCATION

FIELD OF INVENTION

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus about inter-UE coordination for SL resource allocation.

BACKGROUND OF THE INVENTION

In 5G new radio, V2X sidelink (SL) communication can be supported by the unicast, groupcast and broadcast communications. Moreover, the inter-UE coordination can be used to assist the SL resource allocation for performance improvement.

For SL resource allocation, the assisted UE can request the assisting UEs to provide the inter-UE coordination message which can help assisted UE to perform resource allocation. Whether/how to send the request message is critical for the latency, the overhead and the performance.

SUMMARY OF THE INVENTION

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus about inter-UE coordination for SL enhancement. The UE can request the other UE (s) to provide the information about the preferred resources for transmission. Such request can be realized by PSFCH based physical channel, 1st SCI and/or 2nd SCI based SL control information, and/or MAC-CE based physical data channel. The container for the request can be selected depending on the contents of the request and QoS requirement (latency, congestion control, etc) . The request can sent via the (pre-) configured resources. Moreover, the resource for the request transmission can be SL pair specific, e.g., derived based on the both UEs’ IDs.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of the present disclosure. The drawings illustrate implementations of the disclosure and, together with the description, serve to explain the principles of the disclosure. It is appreciable that the drawings are not necessarily in scale as some components may be shown to be out of proportion than the size in actual implementation in order to clearly illustrate the concept of the present disclosure.

FIG. 1 shows an exemplary block diagram of a UE (a.k.a device) according to an embodiment of the disclosure.

FIG. 2 shows the procedure for illustration according to an embodiment of the disclosure.

DETAILED DESCRIPTION

Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to ... " . Also, the term "couple" is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections. The making and using of the embodiments of the disclosure are discussed in detail below. It should be appreciated, however, that the embodiments can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative, and do not limit the scope of the disclosure. Some variations of the embodiments are described. Throughout the various views and illustrative embodiments, like reference numbers are used to designate like elements.

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. Note that the 3GPP specifications described herein are used to teach the spirit of the invention, and the invention is not limited thereto.

The UE can request the other UE (s) to provide the information about the preferred resources for transmission. Such request can be realized by PSFCH based physical channel. PSFCH based physical channel is sequence based physical channel. One PSFCH resource (one time and/or frequency and/or sequence resource) is used for sending the request for one directional or bi-directional SL connection. The PSFCH resource for transmission of the request can be selected from PSFCH resource set which is (pre-) configured per BWP or resource pool. The resources in the PSFCH resources set for the transmission of the request can be ordered in time (slot level) , frequency (RB level) and/or sequence level. For example, in the time domain, the PSFCH resources for transmission of the request can be (pre-) configured, e.g., one occasion every N slots. Each occasion is corresponding to the (pre-) configured or pre-defined symbol (s) in a slot, e.g., symbol#12 and symbol#13 in a slot. Symbol#12 and symbol#13 are repeated for transmission of the request. The first symbol, e.g., symbol#12 can also assist AGC operation in the receiving UE.

A UE can be (pre-) configured to send the request based on the certain condition (e.g., the buffer status, packet arrival, packet high priority, UE capability and the peer UE capability to support this feature) . The peer UE may also indicate its capability or provide the configuration via PC5-RRC signaling or the field in 1 ^st and/or 2 ^nd SCI that it can’t receive the request message. Or the transmission of the request by the UE can be enabled/disabled by the peer Tx UE via PC5-RRC signaling or the field in 1 ^st and/or 2 ^nd SCI.

The maximum number of the repetitions for transmission of the request can be (pre-) configured per BWP or per resource pool for a UE. For repetitions of the request, the UE may change the resources for the request per repetition, e.g., the time/frequency/sequence resources for repetitions of the request. The change of the resources can be determined based on a function of the repetition number and/or the pre-defined pattern. For example, the first transmission is based on resource 1 and the 2 ^nd transmission is based on resource 2. The difference between resource 1 and resources 2 can be determined by an offset between the resources in time/frequency/sequence domain and/or the IDs for UEs transmitting/receiving the request. Such offset or pattern can be (pre-) configured. Or the offset can be randomly selected.

In case of selection of one or a few requests to the other UEs from a set of requests due to restriction of UE capability, the UE can select resources for the transmission of the request (s) corresponding to the traffic or packets with the highest priorities and/or the packets with the smallest (remaining) delay budgets.

In case of collision of the request transmissions with the other data or control channel transmission/reception, the prioritization rule can be applied. For example, the priority of the request can be determined or derived based on the priority of the packet to be transmitted (over the preferred resources derived /indicated from the corresponding response message) . Then the priority for the request transmission can be used to compare with a priority threshold and/or the priority of the other channels to determine which transmission/reception should be prioritized/dropped. Alternatively, the priority of the request can be (pre-)configured or defined by default, especially in case of there is no associated data for transmission.

Additionally, A UE can be (pre-) configured with multiple resources sets for the request transmission. Each resource set can be associated to the different priority level. A UE can select the resource set according to the priority of the packet to be transmitted on the resources derived from the corresponding response message triggered by the request.

A UE can be provided, by sl-Request-Period, a number of slots in a resource pool for a period of request transmission occasion resources. If the number is zero, request transmissions from the UE in the resource pool are disabled.

A UE may be indicated by higher layers to not transmit a request signaling.

Additionally, a UE can be provided, by sl-Request-StartOffset, to determine the starting occasion resources within sl-Request-Period. It can be counted based on the available slots or physical slots. For example,

if (slotNumber mod sl-Request-Period) = sl-Request-StartOffset,

then slotNumber is the occasion for the request transmission.

Alternatively, the occasion for the request transmission can be determined or derived based on the IDs of the UEs transmitting and/or receiving the request. For example, A UE determines a slot index of a resource for the request transmission as:

(Tx_id + Rx_id) mod sl-Request-Period

where Tx_id is an ID for UE transmitting the request and Rx_id is the ID for UE receiving the request.

More specifically, for PSFCH based request transmission, a UE expects that a slot

has a PSFCH based request transmission occasion resource if k mod

and T′ _max is a number of slots for SL transmission that belong to the resource pool within e.g., 10240 msec, and

is provided by sl-Request-Period. And there may or may not have sl-Request-StartOffset in this case.

For PSFCH based request transmission, a UE is provided by sl-PSFCH-Request-RB-Set a set of

PRBs in a resource pool or BWP for PSFCH based request transmission in a PRB of the resource pool or BWP. The starting PRB in the resource pool or SL BWP and the number of PRBs can be (pre-) configured to determine the set of PRBs for transmission of the requests.

The second OFDM symbol l′ of PSFCH based request transmission in a slot is defined as l′= startSLsymbols+ lengthSLsymbols –2, especially in case only part of the symbols in the slot is available for SL transmission.

A UE determines a number of PSFCH resources available for multiplexing request information in a PSFCH transmission as

where

is a number of cyclic shift (pairs) for the resource pool or BWP provided by sl-Request-NumMuxCS (e.g., within a PRB) .

The PSFCH resources for request transmissions are first indexed according to an ascending order of the PRB index, from the set of PRBs for request transmissions, and then according to an ascending order of the cyclic shift (pair) index from the

cyclic shift pairs. Alternatively, it can be ordered firstly according to the cyclic shift (pair) index and then the PRB index.

UE determines an index of a PSFCH resource for a request transmission based on the IDs of UEs transmitting and/or receiving the request as:

(Tx_id + Rx_id) mod

A UE determines a m ₀ value, for computing a value of cyclic shift α [4, TS 38.211] , from a cyclic shift index corresponding to a PSFCH resource index and from

using Table 1.

Table 1: Set of cyclic shift (pairs)

A UE can be (pre-) configured a m _cs value, for computing a value of cyclic shift α [4, TS 38.211] .

The UE can request the other UE (s) to provide the information about the preferred resources for transmission. Such request can be transmitted via 1st SCI and/or 2nd SCI w/or w/o the associated data channel. In this case, one field in the SCI needs to indicate this is the request message for the proper interpretation in the receiving UE. Similarly, the UE can be provided with a set of PRBs or resource pool for the request transmission. The starting PRB index for the request transmission within the set of PRBs or resource pool can be determined by the IDs of the UEs transmitting/receiving the request and the number of PRBs of the resource set or the resource pool.

FIG. 1 shows an exemplary block diagram of a UE (a.k.a device) according to an embodiment of the disclosure. A processor 810 can be configured to perform various functions of embodiments of the invention. The processor 810 can include signal processing circuitry to process received or to be transmitted data according to communication protocols specified in, for example, LTE and NR standards. Additionally, the processor 810 may execute program instructions, for example, stored in the memory 820, to perform functions related with different communication protocols. The processor 810 can be implemented with suitable hardware, software, or a combination thereof. For example, the processor 810 can be implemented with application specific integrated circuits (ASIC) , field programmable gate arrays (FPGA) , and the like, that includes circuitry. The circuitry can be configured to perform various functions of the processor 810.

In one example, the memory 820 can store program instructions that, when executed by the processor 810, cause the processor 810 to perform various functions as described herein. The memory 820 can include a read only memory (ROM) , a random access memory (RAM) , a flash memory, a solid state memory, a hard disk drive, and the like.

The RF module 830 can be configured to receive a digital signal from the processor 810 and accordingly transmit a signal to a base station in a wireless communication network via an antenna 840. In addition, the RF module 830 can be configured to receive a wireless signal from a base station and accordingly generate a digital signal which is provided to the processor 810. The RF module 830 can include digital to analog/analog to digital converters (DAC/ADC) , frequency down/up converters, filters, and amplifiers for reception and transmission operations. For example, the RF module 830 can include converter circuits, filter circuits, amplification circuits, and the like, for processing signals on different carriers or bandwidth parts.

The UE 800 can optionally include other components, such as input and output devices, additional CPU or signal processing circuitry, and the like. Accordingly, the UE 800 may be capable of performing other additional functions, such as executing application programs, and processing alternative communication protocols.

The processes and functions described herein can be implemented as a computer program which, when executed by one or more processors, can cause the one or more processors to perform the respective processes and functions. The computer program may be stored or distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with, or as part of, other hardware. The computer program may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. For example, the computer program can be obtained and loaded into an apparatus, including obtaining the computer program through physical medium or distributed system, including, for example, from a server connected to the Internet.

The computer program may be accessible from a computer-readable medium providing program instructions for use by or in connection with a computer or any instruction execution system. A computer readable medium may include any apparatus that stores, communicates, propagates, or transports the computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable medium can be magnetic, optical, electronic, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. The computer-readable medium may include a computer-readable non-transitory storage medium such as a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM) , a read-only memory (ROM) , a magnetic disk and an optical disk, and the like. The computer-readable non-transitory storage medium can include all types of computer readable medium, including magnetic storage medium, optical storage medium, flash medium and solid state storage medium.

While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. Accordingly, embodiments as set forth herein are intended to be illustrative and not limiting. There are changes that may be made without departing from the scope of the claims set forth below.

FIG. 2 shows the procedure for illustration. UE-B will send the request via PSFCH-like channel, SCI or MAC-CE to UE-A. Upon reception of the request, UE-A will provide the response to UE-B with the preferred resources information via PSFCH-like channel, SCI or MAC-CE to UE-A. then UE-B can derive the resources based on the preferred resources indicated by UE-A and its own sensing results for data transmission, or use the preferred resources indicated by UE-A directly for data transmission.

Claims

A method performed by a UE, comprising:

receiving the (pre-) configuration for transmission of the request message;

determining the resource for transmission of the request message based on IDs of UEs; and transmitting/receiving the request and/or the number of resources.