1，General description of layer 1（层1的基本型描述）
1.1 Relation to other layers（和其他层的关系）
1.1.1 General protocol architecture（一般协议体系结构）
图1显示了围绕物理层(第一层)的NR无线电接口协议体系结构。
物理层接口第二层的介质访问控制(MAC)子层和第三层的无线电资源控制(RRC)层。不同层/子层之间的圆圈表示服务访问点(sap)。
物理层为MAC提供一个传输通道。传输通道的特征是信息如何在无线电接口上传输。MAC为第二层的无线链路控制(RLC)子层提供不同的逻辑通道。逻辑通道的特征是所传输的信息的类型。
1.2，General description of layer 1（层1的基本型描述）
1.2.1 多址接入：
NR物理层的多址接入方案是基于带循环前缀的正交频分复用(OFDM)。对于上行链路，也支持带有CP的离散傅里叶变换-扩展- ofdm (DFT-s-OFDM)。为了支持成对和非成对频谱传输，需要使能FDD (Frequency Division Duplex)和TDD (Time Division Duplex)。
第一层基于资源块以一种不考虑带宽的方式定义，允许NR第一层适应各种频谱分配。一个资源块以给定的子载波间隔跨越12个子载波。
无线电帧的持续时间为10ms，由10个子帧组成，子帧持续时间为1ms。子帧由一个或多个相邻槽组成，每个相邻槽具有14个相邻符号。
1.2.2 物理信道和调制：
The physical channels defined in the downlink are:
- the Physical Downlink Shared Channel (PDSCH),
- the Physical Downlink Control Channel (PDCCH),
- the Physical Broadcast Channel (PBCH),
The physical channels defined in the uplink are:
- the Physical Random Access Channel (PRACH),
- the Physical Uplink Shared Channel (PUSCH),
- and the Physical Uplink Control Channel (PUCCH).
The physical channels defined in the sidelink（旁/副/边/侧 链路，Sidelink用于终端之间不通过网络设备进行直接传输） are:
- the Physical Sidelink Broadcast Channel (PSBCH),
- the Physical Sidelink Control Channel (PSCCH),
- the Physical Sidelink Feedback Channel (PSFCH),
- and the Physical Sidelink Shared Channel (PSSCH).
In addition, signals are defined as reference signals, primary and secondary synchronization signals.
The modulation schemes supported are
- in the downlink, QPSK, 16QAM, 64QAM, and 256QAM,
- in the uplink, QPSK, 16QAM, 64QAM and 256QAM for OFDM with a CP and π/2-BPSK, QPSK, 16QAM, 64QAM and 256QAM for DFT-s-OFDM with a CP
1.2.3 信道编码：
传输块的信道编码方案为准循环LDPC码，每个基图分别具有2个基图和8组奇偶校验矩阵。一个基图用于编码块大于一定大小或初始传输码率高于阈值;否则，使用另一个基本图。在LDPC编码之前，对于较大的传输块，传输块被分割成大小相等的多个代码块。针对PBCH和控制信息的信道编码方案是基于嵌套序列的极性编码。采用针刺法、缩短法和重复法进行速率匹配。
1.2.4 物理层过程：
这涉及到几个物理层过程。物理层所涵盖的这些过程是;
——小区搜索
——功率控制
—上行同步和上行定时控制
—随机访问的相关程序
- harq相关程序
-波束管理和CSI相关程序
-旁链相关程序
-信道接入程序
通过对物理层资源在频域、时域和功率域的控制，在NR中提供了隐式的干扰协调支持。
1.2.5 物理层测量：
无线电特性由UE和网络测量并报告给高层。这些包括:频率内和频率间切换的测量、系统间切换、时间测量和RRM的测量。
系统间切换的测量被定义为支持切换到E-UTRA。
2，物理层规范的文档结构
2.1 Overview:
物理层规范由一个通用文档(TS 38.201)和七个文档(TS 38.202、38.211到38.215和37.213)组成。图2显示了较高层环境中的物理层规范之间的关系。
2.2 TS 38.201: Physical layer; General description
The scope is to describe:
- The contents of the Layer 1 documents (TS 38.200 series);
- Where to find information;
2.3 TS 38.202: Physical layer services provided by the physical layer(物理层提供的服务)
The scope is to describe services provided by the physical layer, and to specify:
- Services and functions of the physical layer（物理层的业务和功能）;
- Model of physical layer of the UE（终端物理层的模型）;
- Parallel transmission of simultaneous physical channels and SRS（SRS和物理信道的并行传输）;
- Measurements provided by the physical layer（物理层的测量）.
2.4 TS 38.211: Physical channels and modulation（物理信道和调制）
The scope is to establish the characteristics of the Layer-1 physical channels, generation of physical layer signals and modulation, and to specify:
- Definition of the uplink, downlink and sidelink physical channels（定义上下行和旁链物理信道）;
- Frame structure and physical resources（帧结构和物理资源）;
- Modulation mapping (BPSK, QPSK, etc)（调制映射）;
- OFDM signal generation;
- Scrambling, modulation and upconversion（置乱、调制和上转换）;
- Layer mapping and precoding（层映射和预编码）;
- Physical shared channel in uplink, downlink and sidelink（上行链路、下行链路和旁链路中的物理共享信道）;
- Reference signal in uplink, downlink and sidelink（上行链路、下行链路和旁链路中的参考信号）;
- Physical random access channel（物理随机接入信道）;
- Primary and secondary synchronization signals（主辅同步信号）.
2.5 TS 38.212: Multiplexing and channel coding（多路复用和信道编码）
The scope is to describe the transport channel and control channel data processing, including multiplexing, channel coding and interleaving, and to specify:
- Channel coding schemes（信道编码方案）;
- Rate matching（速率匹配）;
- Uplink transport channels and control information（上行传输信道和控制信息）;
- Downlink transport channels and control information（下行传输信道和控制信息）;
- Sidelink transport channels and control information（胖链传输信道和控制信息）.
2.6 TS 38.213: Physical layer procedures for control（物理信道的程序控制）
The scope is to establish the characteristics of the physical layer procedures for control, and to specify:
- Synchronization procedures（同步过程）;
- Uplink power control（上行功控）;
- Random access procedure（随机接入过程）;
- UE procedure for reporting control information（UE程序报告控制信息）;
- UE procedure for receiving control information（UE接收控制信息的程序）.
2.7 TS 38.214: Physical layer procedures for data（数据的物理层程序）
The scope is to establish the characteristics of the physical layer procedures for data, and to specify:
- Power control（功控）;
- Physical downlink shared channel related procedures（物理下行共享信道和相关流程）;
- Physical uplink shared channel related procedure（物理上行共享信道相关流程）;
- Physical sidelink shared channel related procedure（物理旁链共享信道和相关流程）.
2.8 TS 38.215: Physical layer measurements（物理信道测量）
The scope is to establish the characteristics of the physical layer measurements, and to specify:
- Control of UE/NG-RAN measurements（UE/NG-RAN测量的控制）;
- Measurement capabilities for NR（NR的测量能力）.
2.9 TS 37.213: Physical layer procedures for shared spectrum channel access（物理层程序用于共享频谱信道的访问）
The scope is to establish the characteristics of the physical layer procedures for shared spectrum channel, and to specify:
- Downlink channel access procedures（下行信道接入过程）;
- Uplink channel access procedures（上行信道接入过程）.