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This standard is one of the standards of LTE-based vehicular communication, of which, the composition and titles are as follows:
a) YD/T 3400-2018 General technical requirements of LTE-based vehicular communication;
b) YD/T 3340-2018 Technical requirements of air interface of LTE-based vehicular communication.
Technical requirements and test methods of corresponding equipment will be formulated subsequently.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by and is under the jurisdiction of China Communications Standards Association.
Introduction
The issuing authority of this document draws attention to the fact that the declaration of conformity with this document may involve the use of patents related to the technical requirements of PC5 interface in Clause 5 and Uu interface in Clause 6.
The issuing body of this document takes no position concerning the evidence, validity and scope of this patent right.
The holder of this patent right has assured the issuing body of this document that he/she is willing to negotiate licenses under reasonable and non-discriminatory terms and conditions with any applicant. The statement of the holder of this patent right is registered with the issuing body of this document. Information may be obtained according to the following contact information.
Name of patent holder: China Academy of Telecom Technology
Address: No. 40, Xueyuan Road, Haidian District, Beijing
Name of patent holder: Huawei Technologies Co., Ltd.
Address: Huawei Base B1, Bantian, Longgang District, Shenzhen, Guangdong
Name of patent holder: ZTE Corporation
Address: ZTE Plaza, No.55 Keji South Road, Nanshan District, Shenzhen, Guangdong
Name of patent holder: China Mobile Communications Corporation
Address: No.28 Financial Street, Xicheng District, Beijing
Name of patent holder: QUALCOMM INCORPORATED
Address: Qualcomm Wireless Communication Technology (China) Co., Ltd., 6F, Tower C, World Trade Center, No.36 North Third Ring East Road, Beijing
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights other than those identified above. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
Technical requirements of air interface of LTE-based vehicular communication
1 Scope
This standard specifies the technical requirements of air interface of LTE-based vehicular communication, including the technical requirements of PC5 interface of sidelink communication between terminals and Uu interface of uplink/downlink communication between terminal and base station; it also specifies the physical layer, MAC layer, RLC layer, PDCP layer and RRC layer in these two working modes and the UE procedure in idle mode.
This standard is applicable to the LTE-based vehicular communication, including V2V, V2I, V2P and V2N communication scenarios.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documents (including any amendments) applies.
YD/T 3340-2018 General technical requirements of LTE-based vehicular communication
3GPP TS 23.285 (Release 14) Technical specification group services and system aspects; architecture enhancements for V2X services
3GPP TS 24.334 (Release 14) Proximity-services (ProSe) user equipment (UE) to ProSe function protocol aspects; Stage 3
3GPP TS 24.386 (Release 14) User equipment (UE) to V2X control function; Protocol aspects: Stage 3)
3GPP TS 36.101 (Release 14) Evolved universal terrestrial radio access (E-UTRA); User equipment (UE) radio transmission and reception
3GPP TS 36.133 (Release 14) Evolved universal terrestrial radio access (E-UTRA): Requirements for support of radio resource management
3GPP TS 36.211 (Release 14) Evolved universal terrestrial radio access (E-UTRA): Physical channels and modulation
3GPP TS 36.212 (Release 14) Evolved universal terrestrial radio access (E-UTRA); Multiplexing and channel coding
3GPP TS 36.213 (Release 14) Evolved universal terrestrial radio access (E-UTRA); Physical layer procedures
3GPP TS 36.214 (Release 14) Evolved universal terrestrial radio access (E-UTRA); Physical layer-measurements
3GPP TS 36.304 (Release 14) Evolved universal terrestrial radio access (E-UTRA); User equipment (UE) procedures in idle mode
3GPP TS 36.321 (Release 14) Evolved universal terrestrial radio access (E-UTRA): Medium access control (MAC) protocol specification
3GPP TS 36.322 (Release 14) Evolved universal terrestrial radio access (E-UTRA): Radio link control (RLC) protocol specification
3GPP TS 36.323 (Release 14) Evolved universal terrestrial radio access (E-UTRA); Packet data convergence protocol (PDCP) specification
3GPP TS 36.331 (Release 14) Evolved universal terrestrial radio access (E-UTRA): Radio resource control (RRC) protocol specification
3 Abbreviations
For the purposes of this document, the following abbreviations apply.
3GPP the 3rd Generation Partnership Project
AM Acknowledged Mode
BSR Buffer Status Report
CBR Channel Busy Ratio
CR Channel Occupancy Ratio
CRC Cyclic Redundancy Check
CSI Channel Status Indicator
DCI Downlink Control Information
DL Downlink
DFN Direct Frame Number
DMRS Demodulation Reference Signal
eNB E-UTRAN Node B
E-PDCCH Enhanced Physical Downlink Control Channel
E-UTRA Evolved Universal Terrestrial Radio Access
E-UTRAN Evolved Universal Terrestrial Radio Access Network
FDD Frequency Division Duplex
FDM Frequency Division Multiplex
GNSS Global Navigation Satellite System
IE Information Element
LCID Logical Channel ID
LTE Long Term Evolution
MAC Medium Access Control
MBMS Multimedia Broadcast Multicast Service
MCCH Multicast Control Channel
MCS Modulation and Coding Scheme
MIB Master Information Block
MIB-SL Master Information Block-Sidelink
NAS Non Access Stratum
P2X Pedestrian-to-Everything
PCell Primary Cell
PDCCH Physical Downlink Control Channel
PDCP Packet Data Convergence Protocol
PDU Protocol Data Unit
PLMN Public Land Mobile Network
PPPP ProSe Per-Packet Priority
PRACH Physical Random Access Channel
PRB Physical Resource Block
PSBCH Physical Sidelink Broadcast Channel
PSCCH Physical Sidelink Control Channel
PSSCH Physical Sidelink Shared Channel
PSSS Primary Sidelink Synchronization Signal
PUCCH Physical Uplink Control Channel
PUSCH Physical Uplink Shared Channel
QAM Quadrature Amplitude Modulation
QPSK Quadrature Phase Shift Keying
RB Resource Block
RIV Resource Indication Value
RLC Radio Link Control
RNTI Radio Network Temporary Identifier
RRC Radio Resource Control
RSRP Reference Signal Received Power
SBCCH Sidelink Broadcast Control Channel
SCell Secondary Cell
SCI Sidelink Control Information
SC-FDMA Single Carrier Frequency Division Multiplex Access
SDU Service Data Unit
SFN System Frame Number
SIB System Information Block
SL Sidelink
SL-BCH Sidelink Broadcast Channel
SL-SCH Sidelink Share Channel
SLSS Sidelink Synchronization Signal
SL-RNTI Sidelink RNTI
SL-V-RNTI V2X Sidelink V2X RNTI
SPS Semi-Persistent Scheduling
S-RSRP Sidelink Reference Signal Received Power
S-RSSI Sidelink Received Signal Strength Indicator
SSSS Secondary Sidelink Synchronization Signal
STCH Sidelink Traffic Channel
SyncRef UE the UE as synchronization reference
TDD Time Division Duplex
TDM Time Division Multiplex
TM Transparent Mode
TTI Transmission Time Interval
UE User Equipment
UL Uplink
UL-SCH Uplink Shared Channel
UM Unacknowledged Mode
V2I Vehicle to Infrastructure
V2N Vehicle to Network
V2P Vehicle to Pedestrian
V2V Vehicle to Vehicle
V-RNTIV2X V2X RNTI
4 General
LTE-based vehicular communication technology works in two working mode, one is sidelink communication mode between terminals, in which the air interface between terminals is called PC5 interface; the other is uplink/downlink communication mode between terminal and base station, in which the air interface between terminal and base station is called Uu interface.
Clause 5 specifies the technical requirements of PC5 interface of LTE-based vehicular communication. The sidelink communication mode includes two transmission modes, in which the sidelink transmission mode 3 is resource scheduling and allocation, and the sidelink transmission mode 4 is UE autonomous resources selection, as defined in 7.2.2 of YD/T 3400-2018 General technical requirements of LTE-based vehicular communication.
The correspondence between document structure and content of Clause 5 and 3GPP technical specification is as follows.
——5.1 specifies the technical requirements of physical layer.
——5.1.1 specifies the physical channel and modulation, corresponding to 3GPP TS 36.211 (Release 14).
——5.1.2 specifies the multiplexing and channel coding, corresponding to 3GPP TS 36.212 (Release 14).
——5.1.3 specifies the physical layer procedure, corresponding to 3GPP TS 36.213 (Release 14).
——5.1.4 specifies the physical layer measurement, corresponding to 3GPP TS 36.214 (Release 14).
——5.2 specifies the technical requirements of media access control (MAC) layer, corresponding to 3GPP TS 36.321 (Release 14).
——5.3 specifies the technical requirements of radio link control (RLC) layer, corresponding to 3GPP TS 36.322 (Release 14).
——5.4 specifies the technical requirements of packet data convergence protocol (PDCP) layer, corresponding to 3GPP TS 36.323 (Release 14).
——5.5 specifies the technical requirements of radio resource control (RRC) layer, corresponding to 3GPP TS 36.331 (Release 14).
——5.6 specifies the technical requirements of UE procedure in idle mode, corresponding to 3GPP TS 36.304 (Release 14).
Clause 6 specifies the technical requirements of Uu interface of LTE-based vehicular communication.
The correspondence between document structure and content of Clause 6 and 3GPP technical specification is as follows.
——6.1 specifies the technical requirements of physical layer.
——6.1.1 specifies the physical channel and modulation, corresponding to 3GPP TS 36.211 (Release 14).
——6.1.2 specifies the multiplexing and channel coding, corresponding to 3GPP TS 36.212 (Release 14).
——6.1.3 specifies the physical layer procedure, corresponding to 3GPP TS 36.213 (Release 14).
——6.1.4 specifies the physical layer measurement, corresponding to 3GPP TS 36.214 (Release 14).
——6.2 specifies the technical requirements of media access control (MAC) layer, corresponding to 3GPP TS 36.321 (Release 14).
——6.3 specifies the technical requirements of radio link control (RLC) layer, corresponding to 3GPP TS 36.322 (Release 14).
——6.4 specifies the technical requirements of packet data convergence protocol (PDCP) layer, corresponding to 3GPP TS 36.323 (Release 14).
——6.5 specifies the technical requirements of radio resource control (RRC) layer, corresponding to 3GPP TS 36.331 (Release 14).
——6.6 specifies the technical requirements of UE procedure in idle mode, corresponding to 3GPP TS 36.304 (Release 14).
5 Technical requirements of PC5 interface
5.1 Physical layer
5.1.1 Physical channel and modulation
5.1.1.1 General
5.1.1.1.1 Physical channel
The physical sidelink channel corresponds to a set of resource elements carrying information from higher layers. The sidelink contains the following physical channels.
——Physical Sidelink Shared Channel, PSSCH.
——Physical Sidelink Control Channel, PSCCH.
——Physical Sidelink Broadcast Channel, PSBCH.
Figure 1 specifies the processing procedure of baseband signal of physical sidelink channel.
Figure 1 Overview of processing procedure of baseband signal in physical sidelink channel
5.1.1.1.2 Physical signal
The physical sidelink signal is used by the physical layer but does not carry information from the higher layer. The sidelink contains the following physical signals:
——DMRS;
——Synchronization signal.
5.1.1.2 Time slot structure and physical resources
5.1.1.2.1 Radio frame structure
The transmission of sidelink is composed of radio frames with a length of Tf, and each radio frame contains 20 time slots with a length of Tslot. A sidelink subframe contains two contiguous time slots, starting from an even-numbered slot. Wherein, Tf=307200×Ts=10ms, Tslot=15360·Ts=0.5ms, Ts=1/(15000×2048). The sidelink radio frame structure is shown in Figure 2.
Figure 2 Sidelink radio frame structure
5.1.1.2.2 Resource grid
A physical sidelink channel or signal contains subcarriers and SC-FDMA symbols in a time slot. When the serving cell and the sidelink have the same uplink frequency and meet the S criterion according to 5.2.3.2 of 3GPP TS 36.304 (Release 14), the bandwidth of the sidelink is , and the bandwidth in other cases is a configurable value (defined in 5.5).
The PSSCH, PSCCH, PSBCH and synchronization signals of the sidelinks configured for transmission mode 3 and transmission mode 4 only support the normal cyclic prefix.
The resource grids are shown in Figure 3.
Figure 3 Sidelink resource grids
An antenna port is defined as the channel to which one symbol transmitted at the antenna port belongs, which may be inferred from the channel to which another symbol transmitted at the same antenna port belongs. Each antenna port corresponds to a resource grid, and the antenna ports used for physical channel or signal transmission are shown in Table 1.
Table 1 Antenna ports used for different physical channels and signals
Physical channel or signal Antenna port number
PSSCH 1000
PSCCH 1000
PSBCH 1010
Synchronization signal 1020
5.1.1.2.3 Resource elements
Every element in the resource grid is called a resource element, and (k, l) is uniquely indicated by an index in a time slot. Wherein, k=0, …, , l=0, …, represent the number in frequency domain and time domain respectively.
The resource element (k, l) on the antenna port p corresponds to a complex number , and the index pp may be omitted where no confusion will be caused or no specific antenna port is designated.
If a resource element is not used to transmit physical channel or physical signal, the value of shall be set to 0.
5.1.1.2.4 Resource block
A resource block is defined as contiguous SC-FDMA symbols and contiguous frequency-domain subcarriers in the time domain, see Table 2 for and . A physical resource block is composed of resource elements, which respectively correspond to a time slot in a time domain and 180kHz in a frequency domain.
Table 2 Physical resource block parameters
Configuration
Normal cyclic prefix 12 7
Extended cyclic prefix 12 6
The relationship between physical resource block number nPRB and the resource element (k, l) in a time slot is shown in Equation (1).
(1)
5.1.1.2.5 Resource pool
5.1.3 defines the subframe pool and resource block pool.
For PSSCH, the current time slot number in the subframe pool is , where i∈{0,1} is the number of the current time slot in the current sidelink subframe , k is equal to the footnote of , is defined by sidelink transmission mode 3 in 5.1.3.2.1.2 and by sidelink transmission mode 4 in 5.1.3.2.1.3.
5.1.1.2.6 Guard interval
The last SC-FDMA symbol of the sidelink subframe serves as a guard interval and cannot be used for the transmission of sidelink.
5.1.1.3 PSSCH
5.1.1.3.1 Scrambling
Bit blocks b(0), ..., b(Mbit-1) transmitted on PSSCH within a subframe (where Mbit is the number of transmitted bits) shall be scrambled according to 5.3.1 of 3GPP TS 36.211 (Release 14).
Scrambling sequence shall be initialized at the beginning of each PSSCH subframe according to , where, for sidelink transmission modes 3 and 4, , p and L are given in 5.1.1 of 3GPP TS 36.212 (Release 14), is equal to the decimal representation of CRC check code of PSCCH transmitted in the same subframe as PSSCH.
5.1.1.3.2 Modulation
Conduct modulation according to 5.3.2 of 3GPP TS 36.211 (Release 14). See Table 3 for the modulation mode of PSSCH.
Table 3 Modulation mode of PSSCH
Physical channel Modulation mode
PSSCH QPSK, 16QAM
5.1.1.3.3 Layer mapping
Conduct layer mapping according to 5.3.2A of 3GPP TS 36.211 (Release 14), assuming that there is only one antenna port with v=1.
5.1.1.3.4 Transform precoding
Conduct transform precoding according to 5.3.3 of 3GPP TS 36.211 (Release 14), and replace and with and respectively.
5.1.1.3.5 Pre-coding
Conduct pre-coding according to 5.3.3A of 3GPP TS 36.211 (Release 14), and it shall be assumed that there is only one antenna port with v=1.
5.1.1.3.6 Physical resource mapping
Multiply complex symbol blocks z(0), ..., z( ) by the amplitude scaling factor βPSSCH to adjust the transmission power PPSSCH (defined in 5.1.3.2.1.5), and then map to the physical resource blocks allocated to PSSCH for transmission on the antenna port p in a sequence from z(0). The mapping to the resource elements (k, l) starts from the first time slot of the subframe, and the index k is increased first, and then the index l is increased, wherein the resource elements (k, l) are those except for reference signal transmission in the above resource block for transmission. The resource elements of the last SC-FDMA symbol in a subframe need to be counted in the mapping procedure but cannot be used for transmission.
V2X communication does not support sidelink hopping, and the physical resource block for transmission is nPRB=n′VRB, where n′VRB is provided in 5.1.3.
Foreword i
Introduction ii
1 Scope
2 Normative references
3 Abbreviations
4 General
5 Technical requirements of PC5 interface
5.1 Physical layer
5.2 MAC Layer
5.3 RLC Layer
5.4 PDCP layer
5.5 RRC layer
5.6 UE procedure in idle mode
6 Technical requirements of Uu interface
6.1 Physical layer
6.2 MAC Layer
6.3 RLC layer
6.4 PDCP layer
6.5 RRC layer
6.6 UE procedure in idle mode
基于LTE的车联网无线通信技术空中接口技术要求
1 范围
本标准规定了基于LTE的车联网无线通信技术的空中接口技术要求,包括终端之间直通链路通信方式的PC5接口技术要求,以及终端与基站之间的上/下行链路通信方式的Uu接口技术要求;规定了这两种工作方式下的物理层、MAC层、RLC层、PDCP层、RRC层以及空闲模式下的UE过程。
本标准适用于基于LTE的车联网无线通信系统,包括V2V、V2I、V2P、V2N通信场景。
2 规范性引用文件
下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件,仅注日期的版本适用于本文件。凡是不注日期的引用文件,其最新版本(包括所有的修改单)适用于本文件。
YD/T 3340—2018 基于LTE的车联网无线通信技术 总体技术要求
3GPP TS 23.285(Release 14)服务和系统方面技术规范组;V2X服务架构增强(“Technical Specification Group Services and System Aspects;Architecture enhancements for V2X services”)
3GPP TS 24.334(Release 14)邻近服务用户设备邻近服务功能协议;阶段3(“Proximity-services (ProSe)User Equipment(UE)to ProSe function protocol aspects;Stage 3”)
3GPP TS 24.386(Release 14)用户设备V2X控制功能;协议;阶段3(“User Equipment(UE)to V2X control function;protocol aspects:Stage 3”)
3GPP TS 36.101(Release 14)演进通用陆地无线接入(E-UTRA);用户设备无线发送与接收(“Evolved Universal Terrestrial Radio Access(E-UTRA);User Equipment(UE)radio transmission and reception”)
3GPP TS 36.133(Release 14)演进通用陆地无线接入(E-UTRA);支持无线资源管理功能的要求(“Evolved Universal Terrestrial Radio Access(E-UTRA);Requirements for support of radio resource management”)
3GPP TS 36.211(Release 14)演进通用陆地无线接入(E-UTRA);物理信道和调制(“Evolved Universal Terrestrial Radio Access(E-UTRA):Physical channels and modulation”)
3GPP TS 36.212(Release 14)演进通用陆地无线接入(E-UTRA);复用和信道编码(“Evolved Universal Terrestrial Radio Access(E-UTRA);Multiplexing and channel coding”)
3GPP TS 36.213(Release 14)演进通用陆地无线接入(E-UTRA);物理层过程(“Evolved Universal Terrestrial Radio Access(E-UTRA);Physical layer procedures”)
3GPP TS 36.214(Release 14)演进通用陆地无线接入(E-UTRA);物理层测量(“Evolved Universal Terrestrial Radio Access(E-UTRA);Physical layer-Measurements”)
3GPP TS 36.304(Release 14)演进通用陆地无线接入(E-UTRA);空闲模式下的UE过程(“Evolved Universal Terrestrial Radio Access(E-UTRA);User Equipment(UE)procedures in idle mode”)
3GPP TS 36.321(Release 14)演进通用陆地无线接入(E-UTRA):媒体接入控制(MAC)协议规范(“Evolved Universal Terrestrial Radio Access(E-UTRA):Medium Access Control(MAC)protocol specification”)
3GPP TS 36.322(Release 14)演进通用陆地无线接入(E-UTRA);无线链路控制(RLC)协议规范(“Evolved Universal Terrestrial Radio Access(E-UTRA):Radio Link Control(RLC)protocol specification”)
3GPP TS 36.323(Release 14)演进通用陆地无线接入(E-UTRA);分组数据汇聚协议(PDCP)规范(“Evolved Universal Terrestrial Radio Access(E-UTRA);Packet Data Convergence Protocol(PDCP)Specification”)
3GPP TS 36.331(Release 14)演进通用陆地无线接入(E-UTRA);无线资源控制(RRC)协议规范(“Evolved Universal Terrestrial Radio Access(E-UTRA):Radio Resource Control(RRC)Protocol specification”)
3 缩略语
下列缩略语适用于本文件。
3GPP 第三代合作伙伴计划 the 3rd Generation Partnership Project
AM 确认模式 Acknowledged Mode
BSR 缓存状态报告 Buffer Status Report
CBR 信道忙率 Channel Busy Ratio
CR 信道占用率 Channel Occupancy Ratio
CRC 循环冗余码校验 Cyclic Redundancy Check
CSI 信道状态指示 Channel Status Indicator
DCI 下行链路控制信息 Downlink Control Information
DL 下行链路 Downlink
DFN 直接帧序号 Direct Frame Number
DMRS 解调参考信号 Demodulation Reference Signal
eNB 演进型基站 E-UTRAN Node B
E-PDCCH 增强物理下行控制信道 Enhanced Physical Downlink Control Channel
E-UTRA 演进型通用陆地无线接入 Evolved Universal Terrestrial Radio Access
E-UTRAN 演进型通用陆地无线接入网 Evolved Universal Terrestrial Radio Access Network
FDD 频分双工 Frequency Division Duplex
FDM 频分复用 Frequency Division Multiplex
GNSS 全球导航卫星系统 Global Navigation Satellite System
IE 信息元素 Information Element
LCID 逻辑信道标识 Logical Channel ID
LTE 长期演进 Long Term Evolution
MAC 媒体控制接入 Medium Access Control
MBMS 多媒体广播多播业务 Multimedia Broadcast Multicast Service
MCCH 多播控制信道 Multicast Control Channel
MCS 调制编码方式 Modulation and Coding Scheme
MIB 主信息块 Master Information Block
MIB-SL 直通链路主信息块 Master Information Block-Sidelink
NAS 非接入层 Non Access Stratum
P2X 行人对外界 Pedestrian-to-Everything
PCell 主小区 Primary Cell
PDCCH 物理下行控制信道 Physical Downlink Control Channel
PDCP 分组数据汇聚协议 Packet Data Convergence Protocol
PDU 协议数据单元 Protocol Data Unit
PLMN 公共陆地移动网络 Public Land Mobile Network
PPPP 邻近业务数据包优先级 ProSe Per-Packet Priority
PRACH 物理随机接入信道 Physical Random Access Channel
PRB 物理资源块 Physical Resource Block
PSBCH 物理直通链路广播信道 Physical Sidelink Broadcast Channel
PSCCH 物理直通链路控制信道 Physical Sidelink Control Channel
PSSCH 物理直通链路共享信道 Physical Sidelink Shared Channel
PSSS 直通链路主同步信号 Primary Sidelink Synchronisation Signal
PUCCH 物理下行链路控制信道 Physical Uplink Control Channel
PUSCH 物理下行链路共享信道 Physical Uplink Shared Channel
QAM 正交幅度调制 Quadrature Amplitude Modulation
QPSK 正交移向键控 Quadrature Phase Shift Keying
RB 资源块 Resource Block
RIV 资源指示值 Resource Indication Value
RLC 无线链路控制 Radio Link Control
RNTI 无线网络临时标识 Radio Network Temporary Identifier
RRC 无线资源控制 Radio Resource Control
RSRP 参考信号接收功率 Reference Signal Received Power
SBCCH 直通链路广播控制信道 Sidelink Broadcast Control Channel
SCell 辅小区 Secondary Cell
SCI 直通链路控制信息 Sidelink Control Information
SC-FDMA 单载波频分多址接入 Single Carrier Frequency Division Multiplex Access
SDU 业务数据单元 Service Data Unit
SFN 系统帧序号 System Frame Number
SIB 系统信息块 System Information Block
SL 直通链路 Sidelink
SL-BCH 直通链路广播信道 Sidelink Broadcast Channel
SL-SCH 直通链路共享信道 Sidelink Share Channel
SLSS 直通链路同步信号 Sidelink Synchronisation Signal
SL-RNTI 直通链路无线网络临时标识 Sidelink RNTI
SL-V-RNTI V2X直通无线网络临时标识 Sidelink V2X RNTI
SPS 半持续调度 Semi-Persistent Scheduling
S-RSRP 直通参考信号接收功率 Sidelink Reference Signal Received Power
S-RSSI 直通链路接收信号强度指示 Sidelink Received Signal Strength Indicator
SSSS 直通链路辅同步信号 Secondary Sidelink Synchronisation Signal
STCH 直通链路传输信道 Sidelink Traffic Channel
SyncRef UE 同步源终端 the UE as synchronization reference
TDD 时分双工 Time Division Duplex
TDM 时分复用 Time Division Multiplex
TM 透明模式 Transparent Mode
TTI 传输时间间隔 Transmission Time Interval
UE 用户设备 User Equipment
UL 上行信道 Uplink
UL-SCH 上行链路共享信道 Uplink Shared Channel
UM 无确认模式 Unacknowledged Mode
V2I 车辆对基础设施 Vehicle to Infrastructure
V2N 车辆对网络 Vehicle to Network
V2P 车辆对行人 Vehicle to Pedestrian
V2V 车辆对车辆 Vehicle to Vehicle
V-RNTI V2X无线网络临时标识 V2X RNTI
4 概述
基于LTE的车联网无线通信技术分为两种工作方式,一种是终端之间直通链路通信方式,其中终端之间的空中接口称为PC5接口;另一种是终端与基站之间的上/下行链路通信方式,其中终端和基站之间的空中接口称为Uu接口。
第5章规定基于LTE的车联网无线通信技术的PC5接口技术要求。直通链路通信方式包括两种发送模式,其中直通链路发送模式3为资源调度分配,直通链路发送模式4为UE自主资源选择具体定义见YD/T 3340-2018《基于LTE的车联网无线通信技术总体技术要求》的7.2.2。
第5章文档结构及文档内容与3GPP技术规范的对应关系如下。
——5.1规定物理层技术要求。
——5.1.1规定物理信道和调制,对应3GPP TS 36.211(Release 14)。
——5.1.2规定复用和信道编码,对应3GPP TS 36.212(Release 14)。
——5.1.3规定物理层过程,对应3GPP TS 36.213(Release 14)。
——5.1.4规定物理层测量,对应3GPP TS 36.214(Release 14)。
——5.2规定媒体接入控制(MAC)层技术要求,对应3GPP TS 36.321(Release 14)。
——5.3规定无线链路控制(RLC)层技术要求,对应3GPP TS 36.322(Release 14)。
——5.4规定分组数据汇聚协议(PDCP)层技术要求,对应3GPP TS 36.323(Release 14)。
——5.5规定无线资源控制(RRC)层技术要求,对应3GPP TS 36.331(Release 14)。
——5.6规定空闲模式下的UE过程技术要求,对应3GPP TS 36.304(Release 14)。
第6章规定基于LTE的车联网无线通信技术的Uu接口技术要求。
第6章文档结构及文档内容与3GPP技术规范的对应关系如下:
——6.1规定物理层技术要求。
——6.1.1规定物理信道和调制,对应3GPP TS 36.211(Release 14)。
——6.1.2规定复用和信道编码,对应3GPP TS 36.212(Release 14)。
——6.1.3规定物理层过程,对应3GPP TS 36.213(Release 14)。
——6.1.4规定物理层测量,对应3GPP TS 36.214(Release 14)。
——6.2规定媒体接入控制(MAC)层技术要求,对应3GPP TS 36.321(Release 14)。
——6.3规定无线链路控制(RLC)层技术要求,对应3GPP TS 36.322(Release 14)。
——6.4规定分组数据汇聚协议(PDCP)层技术要求,对应3GPP TS 36.323(Release 14)。
——6.5规定无线资源控制(RRC)层技术要求,对应3GPP TS 36.331(Release 14)。
——6.6规定空闲模式下的UE过程技术要求,对应3GPP TS 36.304(Release 14)。
5 PC5接口技术要求
5.1 物理层
5.1.1 物理信道和调制
5.1.1.1 概述
5.1.1.1.1 物理信道
直通链路物理信道对应于一组携带源自高层信息的资源元素。直通链路中包含如下的物理信道。
——直通链路物理共享信道,PSSCH。
——直通链路物理控制信道,PSCCH。
——直通链路物理广播信道,PSBCH。
如图l所示,规定了物理直通链路信道基带信号的处理过程。
码字
层
天线端口
加扰
调制
交换预编码映射
资源单元
SC-FDMA信号产生
层映射
预编码
加扰
调制
交换预编码
资源单元映射
SC-FDMA信号产生
图1 直通链路物理信道基带信号的处理过程综述
5.1.1.1.2物理信号
真通链路物理信号由物理层使用但不携带来源于高层的信息。直通链路中包含如下的物理信号:
——解调参考信号;
——同步信号。
5.1.1.2时隙结构和物理资源
5.1.1.2.1无线帧结构
直通链路的发送是由长度为Tf的无线帧组成,每个无线帧包含20个长度为Tslot的时隙。一个直通链路子帧包含两个连续的时隙,并从偶数时隙起始。其中Tf=307200×Ts=10ms,Tslot=15360·Ts=0.5ms,Ts=1/(15000×2048)。直通链路无线帧结构如图2所示。
无线帧,Tf=307200Ts=10ms
时隙,Tslot=15360Ts=0.5ms
子帧
图2 直通链路无线帧结构
5.1.1.2.2 资源格
一个直通链路物理信道或信号在一个时隙内包含 的子载波和 个SC-FDMA符号。当服务小区和直通链路拥有相同的上行频率,并且按3GPP TS 36.304(Release 14)5.2.3.2满足S准则,直通链路的带宽为 ,其他情况下的带宽是一个可配置的数值(5.5定义)。
配置为发送模式3和发送模式4的直通链路的PSSCH、PSCCH、PSBCH和同步信号只支持常规循环前缀。
资源格如图3所示。
上行链路时隙Tslot
符号
资源块
资源单元
子载波
子载波
资源单元(k,l)
图3 直通链路资源格
天线端口定义为在该天线端口发送的一个符号所属的信道,可以从在同一天线端口发送的另一个符号所属的信道推断出来。每一个天线端口对应一个资源格,物理信道或信号发送使用的天线端口见表1。
表1 不同物理信道和信号使用的天线端口
物理信道或信号 天线端口序号
PSSCH 1000
PSCCH 1000
PSBCH 1010
同步信号 1020
5.1.1.2.3 资源元素
在资源格中的每一个元素叫作资源元素,通过在一个时隙中的索引对(k,l)进行唯一指示。其中k=O,…, ,l=O,…, 分别表示在频域和时域的序号。
在天线端口p上的资源元素(k,l)对应于一个复数 ,在不至于混淆或没有指定特定的天线端口的情况下,索引pp可省略。
如果一个资源元素没有用于传输物理信道或物理信号, 的值应设为0。
5.1.1.2.4 资源块
一个资源块定义为时域上 个连续的SC-FDMA符号和 个连续的频域子载波, 和 见表2。一个物理资源块由 个资源元素组成,分别对应时域中的一个时隙和频域中的180kHz。
表2 物理资源块参数
配置
常规循环前缀 12 7
扩展循环前缀 12 6
一个时隙内物理资源块的编号nPRB和资源元素(k,l)的关系如公式(1)所示。
(1)
5.1.1.2.5 资源池
5.1.3定义了子帧池和资源块池。
对于PSSCH,子帧池中的当前时隙编号为 ,其中i∈{0,1}是在当前直通链路子帧 中的当前时隙的编号,其中k等于 的脚注, 在5.1.3.2.1.2为直通链路发送模式3定义,在5.1.3.2.1.3为直通链路发送模式4定义。
5.1.1.2.6 保护间隔
直通链路子帧的最后一个SC-FDMA符号作为保护间隔,并且不能用作直通链路的发送。
5.1.1.3 直通链路物理共享信道
5.1.1.3.1 加扰
在一个子帧内的PSSCH上发送的比特块b(0),…,b(Mbit-1)(其中Mbit是发送的比特数)应按3GPP TS 36.211(Release 14)5.3.1进行加扰。
加扰序列应在每个PSSCH子帧起始时根据 进行初始化,其中对于直通链路发送模式3和直通链路发送模式4, 、p和L由3GPP TS 36.212(Release 14)5.1.1给出, 等于与PSSCH在同一子帧发送的PSCCH的CRC校验码的十进制表示。
5.1.1.3.2 调制
按3GPP TS 36.211(Release 14)5.3.2进行调制。PSSCH的调制方式见表3。
表3 PSSCH调制方式
物理信道 调制方式
PSSCH QPSK、16QAM
5.1.1.3.3 层映射
按3GPP TS 36.211(Release 14)5.3.2A进行层映射,假设只有单独一个天线端口,v=l。
5.1.1.3.4 变换预编码
按3GPP TS 36.211(Release 14)5.3.3进行变换预编码,分别将其中的 和 替换成 和 。
5.1.1.3.5 预编码
按3GPP TS 36.211(Release 14)5.3.3A进行预编码,应假设只有单独一个天线端口,v=1。
5.1.1.3.6 物理资源映射
复数符号块z(0),…,z( )乘以幅度缩放因子βPSSCH以调整发送功率PPSSCH(5.1.3.2.1.5定义),然后从z(0)开始按次序映射至天线端口P上分配给PSSCH发送的物理资源块。到资源元素(k,l)的映射从子帧的第一个时隙开始,先是索引k的增加,再是索引l的增加,其中资源元素(k,l)是上述用于发送的资源块中除了参考信号发送之外的资源元素。一个子帧内的最后一个SC-FDMA符号中的资源元素在映射过程中需要被计数但是不能用于发送。
V2X通信不支持直通链路跳频,用于发送的物理资源块为nPRB=n′VRB,其中n′VRB由5.1.3提供。
5.1.1.4 直通链路物理控制信道
5.1.1.4.1 加扰
在一个子帧内的PSCCH上发送的比特块b(0),…,b(Mbit-1)(其中Mbit是发送的比特数)应按3GPP TS 36.211(Release 14)5.3.1进行加扰。
加扰序列发生器应在每个PSCCH子帧起始时根据cinit=510进行初始化。
5.1.1.4.2 调制
按3GPP TS 36.211(Release 14)5.3.2进行调制。PSCCH的调制方式见表4。
表4 PSCCH调制方式
物理信道 调制方式
PSCCH QPSK
5.1.1.4.3 层映射
按3GPP TS 36.211(Release 14)5.3.2A进行层映射,应假设只有单独一个天线端口,v=1。
5.1.1.4.4 变换预编码
按3GPP TS 36.211(Release 14)5.3.3进行变换预编码,将其中的 和 分别替换成 和 。
5.1.1.4.5 预编码
按3GPP TS 36.211(Release 14)5.3.3A进行预编码,假设只有单独一个天线端口,v=1。
5.1.1.4.6 物理资源映射
复数符号块z(0),…,z( )乘以幅度缩放因子βPSCCH以调整发送功率PPSCCH(5.1.3.3.1.2定义),然后从z(0)开始按次序映射至天线端口p上分配给PSCCH发送的物理资源块。到资源元素(k,l)的映射从子帧的第一个时隙开始,先是索引k的增加,再是索引l的增加,其中资源元素(k,l)是上述用于发送的资源块中除了参考信号发送之外的资源元素。一个子帧内的最后一个SC-FDMA符号的资源元素在映射过程中应被计数但不能用于发送。
5.1.1.5 直通链路物理广播信道
5.1.1.5.1 加扰
在一个子帧内的PSBCH上发送的比特块b(0),…,b(Mbit-i)(其中Mbit是发送的比特数)应按3GPP TS 36.211(Release 14)5.3.1进行加扰。加扰序列应在每个PSBCH子帧起始时根据 进行初始化。
5.1.1.5.2 调制
按3GPP TS 36.211(Release 14)5.3.2进行调制。PSBCH的调制方式见表5。
表5 PSBCH调制方式
物理信道 调制方式
PSBCH QPSK
5.1.1.5.3 层映射
按3GPP TS 36.211(Release 14)5.3.2A进行层映射,假设只有单独一个天线端口,v=l。
5.1.1.5.4 变换预编码
按3GPP TS 36.211(Release 14)5.3.3进行变换预编码,分别将其中的 和 替换成 和 。
5.1.1.5.5 预编码
按3GPP TS 36.211(Release 14)5.3.3A进行预编码,假设只有单独一个天线端口,v=1。
5.1.1.5.6 物理资源映射
复数符号块z(0),…,z( )乘以幅度缩放因子βPSBCH以调整发送功率PPSBCH(在5.1.3定义),然后从z(0)开始按次序映射至天线端口P的物理资源块。PSBCH使用和同步信号相同的资源块。到资源元素(k,l)的映射从子帧的第一个时隙开始,先是索引k的增加,再是索引l的增加,其中资源元素(k,l)是用于发送PSBCH的资源块中除了参考信号和同步信号发送之外的资源元素,并且索引k由公式(2)给出。