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）.