What is Peer-to-peer Communication? Introduction to Point-to-point Communication

 

 

Point-to-point communication realizes the exchange of information between any two users in the network. After receiving the data with the point-to-point communication identification information, the radio station compares the system number and address code. When the system number and address code are consistent with the local, the data will be transmitted to the user terminal, otherwise the data will be discarded and not transmitted to the user terminal. In peer-to-peer communication, only 1 user can receive information.

 

 

According to the direction and time of message transmission, it is divided into three types: simplex communication, half-duplex communication, and full-duplex communication.

 

 

2.1.1 Simplex communication: data can only be transmitted in one direction, with a fixed sender and receiver. Such as: remote control.

 

2.1.2 Half-duplex communication: data can be transmitted alternately in both directions, but not at the same time. Such as: walkie-talkie.

 

2.1.3 Full-duplex communication: data can be transmitted in both directions at the same time. For example: telephone.

 

2.2 Detailed explanation

 

2.2.1 Simplex Communication

 

Simplex Communication refers to a working mode in which messages can only be transmitted in one direction.

 

In simplex communication, the communication channel is one-way, and the sender and receiver are also fixed, that is, the sender can only send information, but cannot receive information; the receiver can only receive information, but cannot send information. Based on this situation, the data signal is transmitted from one end to the other end, and the signal flow is unidirectional.

 

For example: broadcasting in life is a simplex communication way of working. The radio station is the sender and the listener is the receiver. Radio stations send information to listeners, and listeners receive information. The broadcasting station cannot obtain the information of the listeners as a receiver, and the listeners cannot send signals to the broadcasting station as a sender.

 

The two sides of the communication adopt "Push To Talk" (Push To Talk, PTT) simplex communication, which belongs to point-to-point communication. According to the similarities and differences of sending and receiving frequencies, simplex communication can be divided into intra-frequency communication and inter-frequency communication.

 

 

Half-duplex communication (Half-duplex Communication) can realize two-way communication, but it cannot be carried out in both directions at the same time, and must be carried out alternately.

 

In this way of working, the sender can be transformed into a receiver; correspondingly, the receiver can also be transformed into a sender. But at the same moment, information can only travel in one direction. Therefore, half-duplex communication can also be understood as a simplex communication that switches directions.

 

For example, the walkie-talkie is the most common half-duplex communication method in daily life. The two parties holding the walkie-talkie can communicate with each other, but at the same time, only one party can speak.

 

 

Full duplex communication means that at any time of communication, there is bidirectional signal transmission from A to B and B to A on the line.
 

Full-duplex communication allows data to be transmitted in both directions at the same time, also known as two-way simultaneous communication, that is, both parties in the communication can send and receive data at the same time. In full-duplex mode, each end of the communication system is provided with a transmitter and a receiver, so that control data can be transmitted in both directions at the same time. The full-duplex mode does not require switching of directions, so there is no time delay caused by the switching operation, which is very beneficial for interactive applications (such as remote monitoring and control systems) that cannot have time delays. This method requires that both sides of the communication have a transmitter and a receiver, and at the same time, two data lines are required to transmit data signals. (May also need control and status lines, as well as ground).

 

In theory, full-duplex transmission can improve network efficiency, but in practice it is only useful with other related devices. For example, a twisted-pair network cable must be used for full-duplex transmission, and the hub (HUB) connected in the middle must also be capable of full-duplex transmission; finally, the network operating system used must also support full-duplex operation , so as to truly exert the power of full-duplex transmission.

 

For example: a computer host connects to a display terminal with a serial interface, and the display terminal has a keyboard. In this way, on the one hand, the characters entered on the keyboard are sent to the host memory; on the other hand, the information in the host memory can be sent to the screen for display. Usually, after entering a character on the keyboard, it will not be displayed first. After the computer host receives the character, it will immediately return it to the terminal, and then the terminal will display the character. In this way, the echoing process of the previous character and the inputting process of the next character are carried out simultaneously, that is, they work in full-duplex mode.

 

Most of the current point-to-point communication is full-duplex communication.

 

 

In recent years, with the rapid development of radio frequency technology, integrated circuit, automatic control, and wireless data communication technology, wireless transmission technology has been mentioned more and more, and the current smart city, smart agriculture, smart factory, etc. all need wireless transmission technology. to support. The following mainly introduces several specific applications of point-to-point wireless communication.

 

 

At present, the development of oilfield automation and intelligence has become a trend. Efficiency and benefit are very important for every link of oilfield exploitation, and they are interlinked. In the process of mining, oil pressure, flow rate, temperature, load, etc. are all important parameters of efficiency and benefit, and are an important part directly related to the stability of oilfield production and the quality of crude oil. Due to the scattered geographical location, the high fluidity of production operations, and the harsh field construction environment, the communication cables of wired communication need to be constantly moved, which will inevitably cause wiring difficulties and cable damage, resulting in high maintenance costs, so we need better way to deal with the problems encountered in practice. The use of wireless transmission can realize the production management of oil fields and the data detection of oil wells, and achieve informationization and automation. Improve work efficiency and improve the working conditions of workers. Once there is an anomaly in the data, it is immediately possible to determine where the problem is in that well. There will be no additional wiring costs due to the transfer of oil wells, which not only reduces the wiring costs but also does not generate subsequent maintenance costs. It has multiple benefits in oilfield exploitation, greatly reducing development costs and improving production efficiency and benefits.

 

The pressure, temperature, displacement, load and infrared information of the oilfield oil pump are sent wirelessly through the wireless digital radio. The remote receiving end receives the data and transmits the data to the computer, and the computer can display the current oil pump in real time. information, achieve real-time monitoring, and improve production efficiency.

 

 

With the rapid development of social economy and the acceleration of urbanization, the area of ??urban areas continues to expand, and various fires and disasters occur frequently. Once a major danger occurs, the 119 command center must maintain uninterrupted contact with the disaster accident site, vehicles on the way, and the duty rooms of various grass-roots squadrons, so that the 119 command center can dispatch fire officers and soldiers and fire trucks to the disaster accident site for disaster relief in a timely and accurate manner. In the command room, dispatch and command should be made in a timely manner according to the rescue situation fed back by the disaster accident site, so as to ensure that the rear commanders can keep abreast of the disaster accident site situation and the real-time dynamics of the reinforcements. Provide reliable information for decision-making. Especially when a large disaster occurs and multi-squadron cross-regional joint operations are carried out, the application of wireless communication in fire protection is of great significance. The wireless communication module detects the voltage, temperature, current, switch status and other information of the power supply equipment, and reports it in real time to prevent potential safety hazards before it occurs. Phase did not occur.

 

The smart power consumption system can store a large amount of data in real time, obtain first-hand data at any time, form a data center, and extract, mine, analyze, and summarize data to provide the basis for important decisions. In the mode of electricity safety supervision, the smart electricity system can realize 7×24-hour all-weather monitoring, get rid of the limitation and inefficiency of manual work, and monitor the operation status of equipment at any time through the Internet of Things system; on the operation side, through the big data system, it can be The user's electricity consumption becomes a visual digital presentation, which can visually display and monitor the safety of electrical operation with graphics; if there are hidden dangers of electricity consumption such as abnormal lines and overloading, the system can activate the alarm mechanism in time to accurately report the fault. In a large area, there are tens of millions of electrical equipment, and the "smart power consumption" system can help the management party to carry out scientific and effective management. The specific method is to use smart power The system, based on the geographic information system, realizes the positioning of monitoring points, the distribution of projects and equipment is clear at a glance, and at the same time monitors the status of regional electricity consumption, realizes the "transparent" management of electrical fire safety, saves time and improves efficiency. In a word, the smart electricity monitoring system has changed the traditional operation and maintenance mode. By establishing an automatic monitoring and management platform, the use of electricity safety supervision has become simpler, so as to eliminate potential safety hazards and achieve the purpose of scientific management.

 

In any field involving data transmission, wireless data transmission can have its place. At present, the wireless transmission technology is developing rapidly, there are more and more wireless module manufacturers, and solutions involving public network transmission and private network transmission are emerging one after another. Compared with public network transmission, private network transmission is more and more accepted by users. First of all, the investment is low. The wired communication method requires laying cables, which consumes material and manpower. The public network module needs to be paid for renting. However, the private network transmission module establishes a dedicated wireless data transmission method. It only needs to connect the wireless data transmission equipment and erect it properly. This is especially obvious in long distances and complex terrains; secondly, the opening is fast. When connecting remote sites with a distance of several kilometers or tens of kilometers to the main station to communicate with each other, the wired method must be used. To erect long-distance cables or dig long cable trenches, this engineering cycle may take several months, while using wireless data transmission equipment to establish dedicated wireless data transmission only needs to erect antennas of appropriate height, and the engineering cycle only takes a few days It is completed; once again, it is highly adaptable, and the limitations of wired communication are too large. When encountering some special application environments, such as encountering special geographical environments such as mountains, lakes, forest areas, roads, buildings, etc., or wiring comparisons such as moving objects When the application environment is difficult, it will have a strong restriction on the wiring project of the wired network, and the method of establishing dedicated wireless data transmission with wireless data transmission equipment will not be subject to these restrictions; finally, the scalability of the dedicated network transmission is also relatively strong. After users set up a communication network, new equipment is often added due to the needs of the system. If the wired method is used, re-wiring is required, the construction is more troublesome, and the original communication line may be damaged. Or the WiFi module, ZigBee module, lora module, Bluetooth module, etc.) can be connected to realize the expansion of the system.