WO2021212459A1

WO2021212459A1 - Physical layer enhancements for sl communication

Info

Publication number: WO2021212459A1
Application number: PCT/CN2020/086641
Authority: WO
Inventors: Tao Chen
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2020-04-24
Filing date: 2020-04-24
Publication date: 2021-10-28
Also published as: CN113556777A

Abstract

For SL PSSCH TBS determination, a PSFCH overhead indicator carried in 2nd SCI can be used to indicate whether the average or zero PSFCH overhead is assumed for a TB across the initial transmission and re-transmission (s). This can secure the same TB across all (re-) transmissions for a TB while providing the possibility of achieving the peak data rate by only using the slots without PSFCH.

Description

PHYSICAL LAYER ENHANCEMENTS FOR SL COMMUNICATION

FIELD OF INVENTION

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus about physical layer enhancement for SL communications.

BACKGROUND OF THE INVENTION

In 5G new radio, V2X sidelink (SL) communication may be supported by the unicast, groupcast and broadcast communications. However, there are several issues to be addressed in physical layer for SL communications.

SUMMARY OF THE INVENTION

For SL PSSCH TBS determination, a PSFCH overhead indicator carried in 2nd SCI can be used to indicate whether the average or zero PSFCH overhead is assumed for a TB across the initial transmission and re-transmission (s) . This can secure the same TB across all (re-) transmissions for a TB while providing the possibility of achieving the peak data rate by only using the slots without PSFCH. SL CSI table is determined explicitly by the signaling or implicitly according to a mapping between CSI table and the used MCS table. Only one CSI reporting process is allowed to avoid the out-or-order delivery of the CSI reports carried in MAC layer suffering from HARQ delay. A reference pattern of TDD configuration can be assumed to derive the UL slots for some TDD patterns.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 shows an exemplary block diagram of a UE (a.k.a device) 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.

For SL PSSCH TBS determination, a PSFCH overhead indicator can be carried in 2nd SCI. It can be used to indicate whether the average or zero PSFCH overhead is assumed for a TB across the initial transmission and re-transmission (s) . In case of the average PSFCH overhead is assumed, the value is derived by the ratio of the total number of PSFCH symbols over the total number of symbols of PSSCH and PSFCH across all slots. For example, given PSFCH resources are configured every 2 slots with 3 symbols of PSFCH resources including the associated GP symbol in the PSFCH slot and total N PSSCH symbols (w/wo AGC symbols) over 2 slots (e.g., 12 symbols in slot w/o PSFCH and 9 symbols in slot with PSFCH if AGC symbol is included) , then the average PSFCH overhead will be 3/ (12+9+3) = 3/24 = 12.5%. The number of PSSCH symbols in a slot is up to resource pool configuration and the presence of the PSFCH resources. Alternatively, the overhead can be defined as the ratio of the total number of PSFCH symbols over the total number of SL symbols in a slot (w/wo GP/AGC symbols) over the period for PSFCH slot configuration.

For SL CSI reporting, there is the association between the CSI trigger and the reported CSI. In case of multiple CSI tables (pre-) configured, an indicator may be needed in (2 ^nd) SCI to indicate which CSI table is assumed for CSI reporting. Alternatively, CSI reporting can be implicitly link to the CSI table which is associated with the MCS table indicated in SCI. That is, the assumed CSI table for CSI reporting and the used MCS table indicated in SCI triggering CSI report can be associated and share the same indicator in SCI. For example, if (1 ^st) SCI indicates using 64QAM MCS table for the data transmission and CSI reporting is also triggered in the corresponding (2 ^nd) SCI, then the 64QAM CSI table corresponding to 64QAM MCS table will be assumed for CSI reporting. To secure the association between the assumed SL CSI table and SL CSI reports, it assumes that there is no multiple CSI reporting in parallel. For example, if one SCI has triggered CSI reporting, the next or new trigger for CSI reporting can be only allowed after receiving the corresponding CSI reports and/or fail to receive CSI reports due to reaching maximum (re-) transmission times and/or exceeding the latency bound for the CSI reporting. Additionally, a timer at the Tx UE triggering CSI reporting. It starts when the CSI reporting is triggered and stops when the corresponding CSI report is received correctly. If the timer is expired or stopped, a new CSI reporting can be triggered. Otherwise, the new CSI reporting is not allowed. In case of SL CA, the multiple CSI-reporting can be supported for a UE. However, there will be at most one ongoing CSI reporting process per CA or per SL BWP or per resource pool for a UE, i.e., no multiple ongoing CSI reporting processes in parallel.

For TDD UL/DL information carried in S-SSB to determine the available SL slots, the indication for single period and dual-period patterns associated with the UL slots per period can be indicated in S-SSB derived from the TDD UL/DL configuration in uu interface (e.g., SIB messages) . Due to the limited bits in S-SSB, not all combinations can be carried. To save the bits, the patterns with the same period for each period in the dual-period, i.e., {P1=n, P2=n} , the same indication can be used with different granularity applied for different n value.

The UL slots in the dual-period patterns with the same period on P1 and P2 can be derived from the UL slots in a reference dual-period pattern indicated in the signaling. For example, for the dual-period pattern {P1, P2} = {5ms, 5ms} , the UL (or SL) slots for the pattern {5ms, 5ms} can be indicated by some bits indicating the consecutive UL (or SL) slots. For the other patterns with the same period in P1 and P2, e.g., {2ms, 2ms} , {2.5ms, 2.5ms} and {10ms, 10ms} , they can refer to indication of UL (or SL) slots in P1 and P2 for {5ms, 5ms} reference pattern to derive the corresponding UL slots in P1 and P2 respectively taking into account the difference of the granularity. That is, for a target dual-period pattern {Pt, Pt} , the UL slots in P1 and P2 can be derived by using the indicated UL slots in P1 and P2 in a reference pattern {Pr, Pr} as such:

UL_slots_ {Pt, Pt} _P1 = floor (UL_slots_ {Pr, Pr} _P1 /Pr *Pt) ,

UL_slots_ {Pt, Pt} _P2 = floor (UL_slots_ {Pr, Pr} _P2 /Pr *Pt) ,

wherein Pt is, e.g., 2ms, 2.5ms and 10ms for the corresponding target dual-period patterns {2ms, 2ms} , {2.5ms, 2.5ms} and {10ms, 10ms} , and Pr is the period of the reference pattern, e.g., 5ms if {5ms, 5ms} dual-period pattern is defined as the reference pattern.

For example,

if the indicated UL_slots_ {5, 5} _P1 = 10 slots in P1, then UL_slots_ {2, 2} _P1 = floor (10/5*2) = 4 slots in P1 period.

if the indicated UL_slots_ {5, 5} _P2 = 15 slots in P2, then UL_slots_ {2, 2} _P2 = floor (15/5*2) = 6 slots in P2 period.

The UL slots associated with a pattern can be derived from the TDD UL/DL configuration indicated in SIB. In case of the different numerology used for SL and uu interface, the UL_slots_ {Pr, Pr} should take into account the numerology difference between SL and uu to derive the number of UL (or potential SL) slots indicated in SL SSB. For example, if uu is using 15khz and SL is 30khz, the UL_slots_SL_u1 = floor (UL_slots_uu_u2 *2^ (u1-u2) ) , wherein u1 and u2 belong to u = {0, 1, 2, 3} corresponding to 15khz, 30khz, 60khz and 120khz numerology.

For prioritization between PSFCH and UL transmission when PSFCH transmission is overlapping with UL transmission other than PUCCH carrying SL HARQ reporting:

When UL transmission is associated with a DCI with the “priority field” (e.g., URLLC case) , the SL transmission is prioritized if the priority level indicated by the “priority field” (e.g., 0 means “high” , 1 means “low” ) in DCI for the associated UL transmission is larger than the UL priority field threshold (e.g., 1 or 0) , and the priority level of PSFCH (e.g., indicated in the associated SCI) is lower than the SL priority threshold. Otherwise the UL transmission is prioritized. (or vice versa, depending on the ascending order or descending order for priority level definition) .

For the other cases, e.g., UL transmission is not associated with a DCI with the “priority field” , then UL transmission is deprioritized if the priority level of PSFCH is higher than SL-threshold, otherwise prioritized.

For prioritization between S-SSB and UL transmission when S-SSB transmission is overlapping with UL transmission other than PUCCH carrying SL HARQ reporting:

When UL transmission is associated with a DCI with the “priority field” (e.g., URLLC case) , the SL transmission is prioritized if the priority level indicated by the “priority field” (e.g., 0 means “high” , 1 means “low” ) in DCI for the associated UL transmission is larger than the UL priority field threshold (e.g., 1 or 0) , and the priority level of S-SSB is lower than the SL priority threshold. Otherwise the UL transmission is prioritized. (or vice versa, depending on the ascending order or descending order for priority level definition) .

For the other cases, e.g., UL transmission is not associated with a DCI with the “priority field” , then UL transmission is deprioritized if the priority level of S-SSB is higher than SL-threshold, otherwise prioritized.

Additionally, msg3 in uu interface can be always prioritized than S-SSB and/or PSFCH transmission in SL. Or it can be up to the (pre-) configuration on whether to prioritize msg3 or not.

FIG. 1 shows an exemplary block diagram of a UE (a. k. adevice) according to an embodiment of the disclosure. A processor 810 can be configured to perform various functions of the UE 800 described above with reference to the embodiments described above. 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.

Claims

A method, comprising:

receiving a (pre-) configuration for SL operation;

obtaining CSI-RS and/or TDD UL/DL configuration; and

performing transmission/reception of data and/or CSI-RS and/or S-SSB transmission/reception.