table of Contents
Chapter 1 Physical Layer Channel Definition
1.1 The nature of the physical channel
1.2 Why classify and plan time-frequency resource REs (divide channels)
1.5 Location of physical layer channels
Chapter 2 Physical Channel Overview
2.1 Overview of physical channels and signals
2.2 Overall view of physical layer reference signal design
2.3 The relationship between physical channels and signals
2.4 Introduction to the physical layer protocol
3. The relationship diagram between physical channels, transmission channels, and logical channels
4. LTE physical channel VS NR physical channel
Chapter 1 Physical Layer Channel Definition
1.1 The nature of the physical channel
(1) Physical layer sub-carrier resources
(2) Time-frequency resources of the physical layer
(3) Physical layer 10ms frame
(4) Physical channel
By classifying the functions of all the two-dimensional wireless time-frequency resource PRBs in the 10ms frame , various physical channels are obtained .
Simply put, a physical channel is to classify a group of people and their time. Each department is equivalent to a channel, and a channel completes the task of a specific goal.
Some departments, some departments are only responsible for finance, some departments are only responsible for production, some departments are responsible for technology, some departments are responsible for strategy, some are responsible for logistics, and some are responsible for human resource management.
And some departments can be responsible for multiple tasks, and they can also be shared by multiple departments to complete their different tasks.
Because the tasks of each department are different, the skills and methods required to complete the task are not exactly the same. This is because the technical realization of the physical channel is different.
Broadcast channel: the company's external marketing department, responsible for publishing company information.
Synchronous signal: the company's external advertisement, through the advertisement, the client (terminal) can obtain the company's name and the contact number of the marketing department (MIB)
Business channel: The business department of the company that can provide business services to customers.
1.2 Why classify and plan time-frequency resource REs (divide channels)
Why should time-frequency resources be classified according to their functions? To divide it into channels?
If you compare a cell of a base station to a company, and regard each subcarrier RE capable of carrying binary as an employee of the company? The above question has a qualitative and understandable answer:
(1) It is conducive to institutionalized organization and management of the company's large and scattered employee REs, and prevents resource confusion.
(2) It is conducive to specialized division and cooperation of various tasks in accordance with the needs of the company's operations. Employees in some departments are responsible for sales, employees in some departments are responsible for finance, and employees in some departments are responsible for production.
(3) Each department performs its own duties, operates independently, and cooperates with each other.
(4) It is beneficial for the company (base station) to provide services to customers (mobile phones). The customers (terminals) first obtain the information of the business department (data channel) through the management department (control channel), and then obtain data transmission through the business department (business channel) Service.
1.3 Definition of channel
Channel: It is the channel through which information is transmitted.
Physical channel: Generally refers to the channel that relies on physical media to transmit information. The time-frequency resources that carry high-level information (layers above the physical layer) are called physical channels.
And here it refers to a physical channel: it refers to a transmission channel that can be constructed to transmit specific types of information based on all the two-dimensional wireless time-frequency resources in a 10ms frame .
In other words, it is a collective term for a set of time-frequency resources PRB that completes the transmission of specific types of information .
Different types of information identify different types of physical channels.
1.4 credible direction
According to the direction in which the channel transmits information, it is divided into a downlink channel and an upper and lower channel.
1.5 Location of physical layer channels
The physical channel is the interface between the physical layer and the MAC layer. The physical layer provides services to the MAC layer in the form of a physical channel, which is similar to that TCP/IP provides different types of application layer ports.
Chapter 2 Physical Channel Overview
2.1 Overview of physical channels and signals
Channel: used for communication between the base station and the terminal at the L2, L3, and App layers above the physical layer.
Signal: Used for communication between the physical layer of the base station and the terminal , and terminates in the physical layer.
2.2 Overall view of physical layer reference signal design
2.3 The relationship between physical channels and signals
2.4 Introduction to the physical layer protocol
3. The relationship diagram between physical channels, transmission channels, and logical channels
The following pictures show from different aspects and from a macro perspective
(1) The relationship between physical channels, transmission channels, and logical channels.
(2) The position of different channels in the wireless air interface protocol stack
3.1 Mapping diagram 1
3.2 Mapping diagram 2
3.3 Mapping diagram 3
3.4 Mapping diagram 4
4. LTE physical channel VS NR physical channel
(1) Downstream
- 5G NR cancels the LTE physical layer control format indicator channel PCFICH and the physical layer hybrid retransmission indicator channel PHICH, and its function is merged into the physical layer control channel PDCCH and is reflected through DCI.
- 5G NR binds the LTE PSS/SSS and PBCH channels together, which is called a synchronization signal block. This is binding, not merging.
- 5R NR cancels the entire cell-level cell reference signal CRS of LTE. Instead, it adds a separate reference signal DMRS for each channel. The main reason for this change is that the bandwidth of 5G is very large and the cell-level The reference signal can no longer reflect the channel conditions of the entire bandwidth. Another reason is that 5G needs to support large-scale antenna arrays and beamforming. In different beam directions, the channel quality is different.
(2) Uplink
- 5G NR adds the uplink channel reference signal DMRS
Chapter 5 Discussion Framework on Follow-up Channels
(1) The role of the channel
(2) The content transmitted by the channel
(3) Frequency domain resources where the channel is located
(4) Time domain resources where the channel is located
Remarks:
This article does not make an in-depth interpretation of various channels and signals. Therefore, the main significance of this article is embodied in the role of the outline.
For specific signals and the connotation of signals, the relevant chapters need to be inquired.