WO2021159468A1

WO2021159468A1 - Methods and apparatus of sl l1-rsrp measurement for v2x communication

Info

Publication number: WO2021159468A1
Application number: PCT/CN2020/075266
Authority: WO
Inventors: Xuanbo SHAO; Zhixun Tang; Min LEI; Tao Chen
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2020-02-14
Filing date: 2020-02-14
Publication date: 2021-08-19

Abstract

In NR sidelink, SL L1-RSRP is used to evaluate the resource reservation whether could be used to transmission signals. There are two different configurations for SL L1-RSRP. The network can configure the UE to use PSSCH channel to calculate the SL L1-RSRP, and also can configure the UE to use PSCCH channel to calculate the SL L1-RSRP. PSCCH -demodulation reference signal (DMRS) can be used to calculate the PSCCH-RSRP. The PSCCH supports only 1 layer transmission. The RSRP calculation can base on the transmission PSCCH symbols and DMRS REs. PSSCH -demodulation reference signal (DMRS) can be used to calculate the PSSCH-RSRP. The PSSCH supports at most 2 layers MIMO transmission. When UE is configured to use PSSCH-RSRP in resource reselection, UE may have to compare the RSRP measured from single antenna port or measured from two antenna ports. There are five scenarios for PSSCH DMRS configuration with different code division multiplexing (CDM) group and different DMRS port (s). The RSRP calculation can base on the transmission PSSCH symbols and DMRS REs.

Description

METHODS AND APPARATUS OF SL L1-RSRP MEASUREMENT FOR V2X COMMUNICATION

FIELD OF INVENTION

This disclosure relates generally to wireless communications, and, more particularly, to methods and requirement for measurement of sidelink 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, e.g., how to perform the measurement and how to define the measurement requirement to evaluate the resource reservation whether could be used to transmit signals.

SUMMARY OF THE INVENTION

This disclosure relates generally to wireless communications, and, more particularly, to methods and requirement for the measurement of sidelink communications.

In NR sidelink, SL L1-reference signal received power (L1-RSRP) is used to evaluate the resource reservation whether could be used to transmission signals. There are two different configurations for SL L1-RSRP. The network can configure the UE to use physical sidelink shared channel (PSSCH) to calculate the SL L1-RSRP, and also can configure the UE to use physical sidelink control channel (PSCCH) to calculate the SL L1-RSRP.

PSCCH -demodulation reference signal (DMRS) can be used to calculate the PSCCH-RSRP. The PSCCH supports only 1 layer transmission. The RSRP calculation can base on the transmission PSCCH symbols and DMRS REs.

PSSCH -demodulation reference signal (DMRS) can be used to calculate the PSSCH-RSRP. The PSSCH supports at most 2 layers MIMO transmission. When UE is configured to use PSSCH-RSRP in resource reselection, UE may have to compare the RSRP of measure from single antenna port or measured from two antenna ports. There are five scenarios for PSSCH DMRS configuration with different code division multiplexing (CDM) group and different DMRS port (s) . The RSRP calculation can base on the transmission PSSCH symbols and DMRS REs.

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 example of sidelink resource grid in one slot.

FIG. 2 shows the PSSCH DMRS pattern with 12 available symbols for PSSCH in one slot according to an embodiment of the disclosure.

FIG. 3 shows the PSSCH DMRS pattern with 11 available symbols for PSSCH in one slot according to an embodiment of the disclosure.

FIG. 4 shows the PSSCH DMRS pattern with 10 available symbols for PSSCH in one slot according to an embodiment of the disclosure.

FIG. 5 shows the PSSCH DMRS pattern with 9 available symbols for PSSCH in one slot according to an embodiment of the disclosure.

FIG. 6 shows the PSSCH DMRS pattern with 8 available symbols for PSSCH in one slot according to an embodiment of the disclosure.

FIG. 7 shows the PSSCH DMRS pattern with 7 available symbols for PSSCH in one slot according to an embodiment of the disclosure.

FIG. 8 shows the PSSCH DMRS pattern with 6 available symbols for PSSCH in one slot according to an embodiment of the disclosure.

FIG. 9 shows the PSSCH DMRS pattern with 5 available symbols for PSSCH in one slot according to an embodiment of the disclosure.

FIG. 10 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.

FIG. 1 shows an example of sidelink resource in one slot, which contains PSCCH data, PSCCH DMRS, PSSCH data and PSSCH DMRS. In frequency domain, it can use all of the DMRS REs in RSRP calculation. In time domain, it can use all of the DMRS symbols in RSRP calculation.

The PSCCH supports only 1 layer transmission, the RSRP calculation can base on the single transmission port to calculate RSRP. There are several possible solutions for PSCCH RSRP calculation. One possible solution is the RSRP value is the sum of the power of all DMRS REs with all configured symbols. Alternatively, the RSRP value can be the largest DMRS power in one PSCCH symbol. Alternatively, the RSRP value can be the average of all DMRS REs’ power. The average factor can be the number of PSSCH REs per symbol.

The PSSCH supports at most 2 layers MIMO transmission. PSSCH can be configured with 1 or 2 CDM groups. In each CDM group, PSSCH DMRS can be configured with one or two antenna port (s) . There are following 5 scenarios for PSSCH multiple antenna patterns.

·Scenario 1: Number of CDM group number = 1, DMRS port 0 or 1 (single ports)

·Scenario 2: Number of CDM group number = 1, DMRS port 0 and 1 (dual ports)

·Scenario 3: Number of CDM group number = 2, DMRS port 0 or 1 (single ports)

·Scenario 4: Number of CDM group number = 2, DMRS port 0 and 1 (dual ports)

·Scenario 5: Number of CDM group number = 2, DMRS port 0 and 2 (dual ports)

Scenario 1 and scenario 2 correspond to the left sub-figure in the FIG. 1, which are configured with one CDM group. The remaining REs in the same DMRS symbol are occupied by PSSCH data. The scenarios 3, scenario 4 and scenario 5 correspond to the right sub-figure in the FIG. 1, which are configured with two CDM groups. In these two CDM group scenarios, if the DMRS port only occupy one CDM group, the other CDM group still doesn’t place the PSSCH data, and remains empty. It use the orthogonal cover code (OCC) to distinguish each antenna port when existing two antenna ports in the same CDM group.

PSSCH-RSRP is used to evaluate whether the resource could be used to transmit signals. Thus, UE should know how to calculate the PSSCH-RSRP of single or two antenna ports. One solution is that PSSCH-RSRP is calculated by summing the all DMRS RE’s power in one symbol and then average it. If there are more than one symbol in time domain, it should also average the RSRP value in time domain.

To make PSSCH DMRS energy per resource element (EPRE) consistent with PSSCH EPRE, The UE1 should boost up the DMRS EPRE. As shown in table 1, in one DMRS CDM group, the ratio of PSSCH EPRE to DMRS EPRE is 0dB, while in two DMRS CDM groups, the ratio is -3dB. The UE2 will receive the signals with the power boosting.

Table 1: The ratio of PSSCH EPRE to DM-RS EPRE

In scenario 1, the CDM group contains DMRS port 0 or port 1. In the symbol containing DMRS, the even resource elements are occupied by PSSCH DMRS with port 0, and the odd resource elements are occupied by PSSCH data with port 0. This symbol’s total power is equivalent to pure PSSCH data symbol’s total power. One possible solution to PSSCH RSRP calculation is the sum of the power of all DMRS REs. Alternatively, the RSRP value can be the average of all DMRS REs’ power. The average factor can be the number of PSSCH DMRS REs.

In scenario 2, the CDM group contains DMRS port 0 and port 1. In the symbol containing DMRS, the even resource elements are occupied by PSSCH DMRS with port 0 and port 1, and the odd resource elements are occupied by PSSCH data with port 0 and port 1. This symbol’s total power is equivalent to pure PSSCH data symbol’s total power. One possible solution to PSSCH RSRP calculation is the sum of DMRS REs’ power of each port, and sum of two ports’ power together. Alternatively, it can select the larger RSRP based on measured in two ports as the final RSRP. Alternatively, the RSRP value can be averaging all DMRS REs’ power and summarize of two ports average power together as the final RSRP value. The average factor can be the number of PSSCH DMRS REs.

In scenario 3, there are two CDM groups, CDM group 0 and CDM group 1. The CDM group 0 has DMRS port 1. The CDM group 1 is empty without PSSCH data. In order to make PSSCH DMRS EPRE consistent with PSSCH EPRE, UE1 should boost 3dB of DMRS RE power for the CDM group 0. When UE2 receives the signals, it should calculate the RSRP based on the sum of DMRS REs’ power. Alternatively, the RSRP value can be the average of all DMRS REs’ power. The average factor can be the number of PSSCH REs per symbol.

In scenario 4, there are two CDM groups, CDM group 0 and CDM group 1. The CDM group 0 has the DMRS port 0 and port 1, and the CDM group 1 is also empty without PSSCH data. So, UE1 should boost 3dB of DMRS RE power for the CDM group 0. When UE2 receives the signals, it should calculate the RSRP based on the sum of two port’s DMRS REs’ power. Alternatively, the RSRP value can be the average of all DMRS REs’ power. The average factor can be the number of PSSCH REs per symbol.

In scenario 5, there are two CDM groups, CDM group 0 and CDM group 1. The CDM group 0 has the DMRS port 0 and the CDM group 1 has the DMRS port 1. But in the PSSCH data RE, each RE is occupied by the DMRS port 0 and DMRS port 1. So, UE1 should boost 3dB of DMRS RE power for the CDM group 0 and CDM group 1, respectively. When UE2 receives the signals, it should calculate the RSRP based on the sum of two port’s DMRS REs’ power. Alternatively, the RSRP value can be the average of all two port’s DMRS REs’ power. The average factor can be the number of PSSCH REs per symbol.

For two antenna ports transmission, there are several possible solutions for PSSCH RSRP calculation. In method 1, it can measure based on only 1 DMRS port, and then enhance 3dB to the result. In method 2, it can measure based on 2 DMRS ports, and sum up the two port’s results. In method 3, it can select the power of the largest RSRP based on the measured in two ports.

The PSSCH configuration is flexible for PSCCH, PSSCH and PSSCH DMRS, which means that the PSCCH symbol, PSSCH symbol, and the PSCCH DMRS symbol are not fixed, it can change flexible.

In FIG. 2, there are 12 available PSSCH symbols from symbol #1 to symbol #12, the symbol #0 is for automatic gain control (AGC) and the symbol #13 is reserved and doesn’ t contain PSSCH. In this case, there are 3 PSSCH DMRS categories. In category 1, the PSSCH DMRS occupy 2 symbols in one slot. If the PSCCH occupy 3 symbols in one slot, the PSSCH DMRS symbols are symbol #4, #10. If the PSCCH occupy 2 symbols in one slot, the PSSCH DMRS symbols are symbol #3, #10. In category 2, the PSSCH occupy 3 symbols in one slot. The PSSCH DMRS symbols are symbol #1, #6, #11. In category 3, the PSSCH occupy 4 symbols in one slot. The PSSCH DMRS symbols always are symbol #1, #4, #7, #10. For category1, The PSSCH RSRP calculation can refer to Fig1’s calculation method in each PSSCH DMRS symbol. In Time domain, it can select the larger power in two symbol or average the two symbol’s power or sum the two symbol’s power as the final RSRP value. For

category

In FIG. 5, there are 9 available PSSCH symbols from symbol #1 to symbol #9, the symbol #0 is for AGC and the symbol #10, #11, #12, #13 are reserved and don’ t contain PSSCH. In this case, there are 2 PSSCH DMRS categories. In category 1, the PSSCH DMRS occupy 2 symbols in time slot. If the PSCCH occupy 3 symbols in one slot, the PSSCH DMRS symbols are symbol #4, #8. If the PSCCH occupy 2 symbols in one slot, the PSSCH DMRS symbols are symbol #3, #8. In category 2, the PSSCH occupy 3 symbols in one slot. The PSSCH DMRS symbols are symbol #1, #4, #7. For category1, The PSSCH RSRP calculation can refer to Fig1’s calculation method in each PSSCH DMRS symbol. In Time domain, it can select the larger power in two symbol or average the two symbol’s power or sum the two symbol’s power as the final RSRP value. For category 2, the first PSSCH DMRS is multiplexing with PSCCH in the same symbol with different frequency resource. The RSRP power can be the measured DMRS RSRP multiplexing a scaling factor. The scaling factor can be the ratio of the total number of REs with the number of PSSCH REs per symbol. Alternatively, the RSRP value can be the average over each RE.

In FIG. 6, there are 8 available PSSCH symbols from symbol #1 to symbol #8, the symbol #0 is for AGC and the symbol #9, #10, #11, #12, #13 are reserved and don’ t contain PSSCH. In this case, there are 2 PSSCH DMRS categories. In category 1, the PSSCH DMRS occupy 2 symbols in one slot. If the PSCCH occupy 3 symbols in one slot, the PSSCH DMRS symbols are symbol #4, #8. If the PSCCH occupy 2 symbols in one slot, the PSSCH DMRS symbols are symbol #3, #8. In category 2, the PSSCH occupy 3 symbols in one slot. The PSSCH DMRS symbols are symbol #1, #4, #7. For category1, The PSSCH RSRP calculation can refer to Fig1’s calculation method in each PSSCH DMRS symbol. In Time domain, it can select the larger power in two symbol or average the two symbol’s power or sum the two symbol’s power as the final RSRP value. For category 2, the first PSSCH DMRS is multiplexing with PSCCH in the same symbol with different frequency resource. The RSRP power can be the measured DMRS RSRP multiplexing a scaling factor. The scaling factor can be the ratio of the total number of REs with the number of PSSCH REs per symbol. Alternatively, the RSRP value can be the average over each RE.

In FIG. 7, there are 7 available PSSCH symbols from symbol #1 to symbol #7, the symbol #0 is for AGC and the symbol #8, #9, #10, #11, #12, #13 are reserved and don’ t contain PSSCH. In this case, there is 1 PSSCH DMRS categories. In this category, the PSSCH DMRS occupy 2 symbols in one slot. The PSSCH DMRS symbols always are symbol #1, #5. The first PSSCH DMRS is multiplexing with PSCCH in the same symbol with different frequency resource. The RSRP power can be the measured DMRS RSRP multiplexing a scaling factor. The scaling factor can be the ratio of the total number of REs with the number of PSSCH REs per symbol. Alternatively, the RSRP value can be the average over each RE.

In FIG. 8, there are 6 available PSSCH symbols from symbol #1 to symbol #6, the symbol #0 is for AGC and the symbol #7, #8, #9, #10, #11, #12, #13 are reserved and don’ t contain PSSCH. In this case, there is 1 PSSCH DMRS categories. In this category, the PSSCH DMRS occupy 2 symbols in one slot. The PSSCH DMRS symbols always are symbol #1, #5. The first PSSCH DMRS is multiplexing with PSCCH in the same symbol with different frequency resource. The RSRP power can be the measured DMRS RSRP multiplexing a scaling factor. The scaling factor can be the ratio of the total number of REs with the number of PSSCH REs per symbol. Alternatively, the RSRP value can be the average over each RE.

In FIG. 9, there are 5 available PSSCH symbols from symbol #1 to symbol #5, the symbol #0 is for AGC and the symbol #6, #7, #8, #9, #10, #11, #12, #13 are reserved and don’ t contain PSSCH. In this case, there is 1 PSSCH DMRS categories. In this category, the PSSCH DMRS occupy 2 symbols in one slot. The PSSCH DMRS symbols always are symbol #1, #5. The first PSSCH DMRS is multiplexing with PSCCH in the same symbol with different frequency resource. The RSRP power can be the measured DMRS RSRP multiplexing a scaling factor. The scaling factor can be the ratio of the total number of REs with the number of PSSCH REs per symbol. Alternatively, the RSRP value can be the average over each RE.

Please note that the examples above are some embodiments of the invention. And the invention is not limited by this.

FIG. 10 shows an exemplary block diagram of a UE 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. 10. 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 embodiments described above with reference to Figs. 1-9. 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 configuration or pre-configuration for sidelink PSCCH and PSSCH; and

Performing time/frequency measurement based on the corresponding DMRS pattern.
The method of claim 1, wherein a configuration or pre-configuration for sidelink PSCCH and PSSCH are resource grid composition including PSCCH, PSCCH DMRS, PSSCH, PSSCH DMRS and/or the additional front-loaded symbol (s) for AGC tuning and/or the additional symbol (s) for guard period.
The method of claim 1, wherein the PSCCH supports 1 layer transmission and the PSSCH supports at most 2 layers MIMO transmission, and the PSSCH can be configured with 1 or 2 CDM group (s) .
The method of claim 1, wherein RSRP measurement value can be calculated based on DMRS pattern.
The method of claim 2, wherein the AGC symbol is fixed and occupied symbol index #0.
The method of claim 2, wherein the PSCCH symbol can be flexible, and each PSCCH symbol contains fixed PSCCH DMRS in frequency domain, which could be occupied resource element index #0, #3, #6, #9.
The method of claim 2, wherein the PSSCH symbol and PSCCH DMRS symbol can be flexible.
The method of claim 3, wherein 1 CDM group and 1 PSSCH DMRS antenna port.
The method of claim 3, wherein 1 CDM group and 2 PSSCH DMRS antenna port.
The method of claim 3, wherein 2 CDM groups and 1 DMRS antenna port, the 1 DMRS port could be occupied CDM group 0, CDM group 1 is empty and without PSSCH data.
The method of claim 3, wherein 2 CDM groups and 2 DMRS antenna ports. The 2 DMRS antenna ports could be occupied CDM group 0, and the CDM group 2 is still empty and without PSSCH data.
The method of claim 3, wherein 2 CDM groups and 2 DMRS antenna ports.The DMRS antenna port 0 could be occupied CDM group 0 and DMRS antenna port 1 could be occupied CDM group 1.
The method of claim 4 or claim 6, wherein the PSCCH DMRS RSRP calculation is the sum of the power of all DMRS REs with two symbols, or the PSCCH DMRS RSRP value can be the largest DMRS power in one PSCCH symbol.
The method of claim 4 or claim 8, wherein the PSSCH RSRP calculation is the sum of the power of all DMRS REs, or the RSRP value can be the average of all DMRS REs’ power. The average factor can be the number of PSSCH DMRS REs.
The method of claim 4 or claim 9, wherein the PSSCH RSRP calculation is the sum of DMRS REs’ power of each port, and sum of two ports’ power together, or it can select the larger RSRP based on measured in two ports as the final RSRP, or the RSRP value can be averaging all DMRS REs’ power and summarize of two ports average power together as the final RSRP value, and the average factor can be the number of PSSCH DMRS REs.
The method of claim 4, claim 10, claim 11, or claim 12, wherein, there are several possible solutions for PSSCH RSRP calculation: measure based on only 1 DMRS port, and then enhance 3dB to the result; measure based on 2 DMRS ports, and sum up the two port’s results; or select the power of the largest RSRP based on the measured in two ports.
The method of claim 7, wherein the PSSCH symbols number could be from 12 to 5, and the PSSCH DMRS symbol could be 2, 3 or 4 symbol, and if PSSCH DMRS is multiplexing with PSCCH in the same symbol with different frequency resource, the RSRP power can be the measured DMRS RSRP multiplexing a scaling factor, wherein the scaling factor can be the ratio of the total number of REs with the number of PSSCH REs per symbol, or the RSRP value can be the average over each RE, wherein in Time domain, it can select the larger power in two symbol or average the two symbol’s power or sum the two symbol’s power as the final RSRP value.