WO2021030975A1

WO2021030975A1 - Nr v2x sl synchronization signals

Info

Publication number: WO2021030975A1
Application number: PCT/CN2019/101128
Authority: WO
Inventors: Tao Chen; Xuanbo SHAO; Zhixun Tang; Min LEI
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2019-08-16
Filing date: 2019-08-16
Publication date: 2021-02-25

Abstract

This disclosure relates to wireless communications, and, more particularly, to methods and apparatus for the synchronization signals of V2X sidelink communications. NR PSS can be m-sequence generated from another polynomial than 145-polynomial used by NR uu PSS to avoid confusion. 131-polynomial or the other polynomial can be used to generate NR SL PSS. Additionally, only one PSS can be selected to secure the good auto-correlation performance while avoiding confusion between two PSS's. In case of two PSS's are selected to potentially reduce the overall detection complexity, the two PSS's can be selected from two different polynomials for the best cross-correlation performance to avoid confusion. Alternatively, if the two PSS's are selected from one polynomials, then their spacing should be around (ceiling or floor) the half of the sequence length, e.g., 64 = ceil (127/2), which can minimize the cross-correlation of two PSS's.

Description

NR V2X SL SYNCHRONIZATION SIGNALS

FIELD OF INVENTION

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus for the synchronization signals of V2X sidelink communications.

BACKGROUND OF THE INVENTION

In NR V2X, NR SL PSS should avoid the confusion with NR uu PSS/SSS in case of co-existence in the same frequency resources. Besides, the NR SL PSS should secure the good auto-correlation performance and good cross-correlation performance between NR SL PSS’s. Therefore, a proper design for NR SL synchronization signals are important for the operation of the NR V2X.

SUMMARY OF THE INVENTION

NR PSS can be m-sequence generated from another polynomial than 145-polynomial used by NR uu PSS to avoid confusion. 131-polynomial or the other polynomial can be used to generate NR SL PSS. Additionally, only one PSS can be selected to secure the good auto-correlation performance while avoiding confusion between two PSS’s. In case of two PSS’s are selected to potentially reduce the overall detection complexity, the two PSS’s can be selected from two different polynomials for the best cross-correlation performance to avoid confusion. Alternatively, if the two PSS’s are selected from one polynomials, then their spacing should be around (ceiling or floor) the half of the sequence length, e.g, 64 = ceil (127/2) , which can minimize the cross-correlation of two PSS’s. Additionally, to avoid the PAPR gap between PSS and the corresponding SSS’s , the proper pairing between the PSS and SSS’s are needed.

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. adevice) 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.

NR SL PSS can be m-sequence generated from another polynomial than 145-polynomial which is used by NR uu PSS to avoid confusion between NR SL PSS and NR uu PSS/SSS. 131-polynomial or the other polynomial can be used to generate NR SL PSS. For example, NR SL PSS can be selected from 131-polynomial as below:

d _{SL_PSS} (n) =1-2x (m)

0≤n＜127

x ₁(i+7) = (x ₁ (i+1) +x ₁ (i) ) mod 2

[x(6) x (5) x (4) x (3) x (2) x (1) x (0) ] = [1 1 1 0 1 1 0]

If the two PSS’s are selected from one polynomial for generation of m-sequence based synchronization signals, then the spacing between two PSS’s can be around (ceiling or floor) the half of the sequence length, e.g, 64 = ceil (127/2) assuming 127 is the sequence length, which can minimize the cross-correlation of two PSS’s according to the m-sequence property, as shown in the equation above. Additionally, to avoid the PAPR gap between PSS and the corresponding SSS’s , the proper pairing between the PSS and SSS’s are needed. In this case, the component of “1-Nid (2) ” is applied in the equation above for a proper pairing between PSS and the corresponding SSS’s . Alternatively, in case of two PSS’s are selected to potentially reduce the cross-correlation in between, the two PSS’s can be selected from two different polynomials for the best cross-correlation performance to avoid confusion or miss-detection. The other polynomial candidates than 145 can be one of the blow polynomials:

D^7+D^3+1 (137)

D^7+D^3+D^2+D^1+1 (143)

D^7+D^4+D^3+D^2+1 (157)

D^7+D^5+D^2+D^1+1 (167)

D^7+D^5+D^3+D^1+1 (171)

D^7+D^5+D^4+D^3+1 (185)

D^7+D^5+D^4+D^3+D^2+D^1+1 (191)

D^7+D^6+1 (193)

D^7+D^6+D^3+D^1+1 (203)

D^7+D^6+D^4+D^1+1 (211)

D^7+D^6+D^4+D^2+1 (213)

D^7+D^6+D^5+D^2+1 (229)

D^7+D^6+D^5+D^3+D^2+D^1+1 (239)

D^7+D^6+D^5+D^4+1 (241)

D^7+D^6+D^5+D^4+D^2+D^1+1 (247)

D^7+D^6+D^5+D^4+D^3+D^2+1 (253)

Alternatively, only one PSS instead of two PSS’s can be selected to secure the good auto-correlation performance while avoiding confusion caused by two NR SL PSS’s .

The corresponding NR SL SSS can be same as NR uu SSS as below. When the Nid (2) can be set as 0 or 1, they are implicitly used for generation of 672 SSS sequences. When the Nid (2) can be only set as 0, it is implicitly used for generation of 336 SSS sequences.

d _SSS (n) = [1-2x ₀ ( (n+m ₀) mod 127) ] [1-2x ₁ ( (n+m ₁) mod 127) ]

0≤n＜127

For the relation between NR SL PSS and NR SL SSS, it can be:

- Option 1 (total 336 sequences) : One PSS is corresponding to 336 SSS sequences.

- Option 2 (total 672 sequences) : Two PSS’s from the same or the different polynomials arecorresponding to the total 672 SSS sequences, i.e., one PSS is corresponding to 336 SSS sequences.

- Option 3 (total 672 sequences) : One PSS is corresponding to 672 SSS sequences.

Alternative, there can be a table to define mapping between the root index N and/or N+64 used in polynomial for NR SL PSS with the relation to the corresponding SSS’s .

For example, the table can be as such. To be noted, Nid (2) will be also used for SSS generation. Table 1 and table 2 show different examples with two root indexes from same or different pplynomial.

Table 1: Example 1 with two root indexes from the same polynomial, e.g., 131

PSS root index	Nid (2)
64	0
0	1

Table 2: Example 2 with two root indexes from the different polynomials

PSS root index	Nid (2)
0 in polynomial 131	0
0 in polynomial 185	1

Moreover, the SS detection complexity between the single PSS and two PSS’s can be shown as below in Table 3:

Table 3. Hypothesis for PSS/SSS detection with different subcarrier spacing

It can be noted that the single PSS will reduce the complexity quite much due to less hypothesis for detection.

Fig. 1 shows an exemplary block diagram of a UE 800 according to an embodiment of the disclosure. The UE 800 can be configured to implement various embodiments of the disclosure described herein. The UE 800 can include a processor 810, a memory 820, and a radio frequency (RF) module 830 that are coupled together as shown in Fig. 1. In different examples, the UE 800 can be a mobile phone, a tablet computer, a desktop computer, a vehicle carried device, and the like.

The processor 810 can be configured to perform various functions of the UE 800 described above with reference to embodiments described before. 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:

Performing generation of the one or two NR SL PSS sequence (s) based on m-sequences.
The method of claim 1, wherein generation of the two NR SL PSS sequences based on m-sequences can be from the same polynomial with the spacing between two PSS’s as the ceiling or floor of the half sequence length.
The method of claim 1, wherein generation of the two NR SL PSS sequence (s) based on m-sequences can be from two different polynomials.
The method of claim 1, wherein generation of the NR SL PSS sequence can be a single NR SL PSS from the other polynomials than the one used for generation of NR uu PSS.