I spent two hours this afternoon studying the principles of GPRS, and got a rough understanding of its basic common sense.
1. Origin of GPRS
Checking the relevant information, this thing was developed on GSM, so what is GSM, simply speaking, it is Global System For Mobile Communication, which belongs to the second generation mobile communication technology (2G), that is, your previous broken mobile phone can access the Internet ( The speed of the network is dying, sending text messages is still more than enough), the technology that can make calls is now in the 5G era! What is GPRS? Or because the 2G network speed is too slow, and 3G cannot be studied, so there is a 2.5G communication technology, that is, GPRS, a technology between 2G and 3G. Compared with the GSM circuit-switching method, GPRS uses a packet-switched transmission method to increase the network speed.
2. GPRS networking
1. Basic common sense:
SGSN: Serving GPRS Support Node GPRS service support node,
Function: record the current location information of the mobile station, and complete the transmission and reception of mobile packet data between the mobile station and the GGSN
GGSN: Gateway GPRS Support Node GPRS gateway support node, can be understood as a router, used to record SGSN information
Functions: (1) Accept sub-packet data from SGSN and convert it into data that can be recognized by the external network, such as Internet protocol such as Ethernet protocol, IP protocol, UDP protocol, etc.
(2) Accept the data from the external network and parse it into data that can be recognized by the SGSG node
(3) Maintain routing table to realize routing and packet forwarding functions
(4) Other functions
Connection method between GGSN and SSGN: such as connection through a switch, coaxial cable for wiring harness, twisted pair Ethernet, optical fiber should be acceptable, optical fiber can be divided into single-mode and multi-mode
Single-mode optical fiber: The core of single-mode optical fiber is relatively thin, the transmission frequency bandwidth, capacity and transmission distance are long, but the laser source is required and the cost is high. It is usually used in buildings or in geographically dispersed environments;
Multimode fiber: The core of multimode fiber is thick, the transmission rate is low, the distance is short, and the overall transmission performance is tolerated, but the cost is low, and it is generally used in a building or in a geographically adjacent environment
2. Brief analysis of networking methods
As shown in the figure above, the mobile phone sends wireless data to the nearby base station through the GSM module (the base station is the large iron tower that is usually seen, the antenna is above, and the equipment room is the controller device below). After processing the data, it is sent to GGSN. After processing the data, GGSN sends it to the extranet, such as the Internet.
3. How to connect between the base station and the base station
There are three ways: wired connection, microwave transmission, satellite transmission
Most of our country uses wired connection, mainly fiber optic access, microwave transmission requires unobstructed at both ends, and is affected by the weather. It is generally seldom used, satellite access is less, and the cost is too high. Generally, satellite access is used in Mount Everest. .
Third, the mobile phone uses GPRS technology to transmit data classification
1. Voice data, after reaching the base station, go to the telephone network
2. Internet data, go to the Internet after reaching the base station
But now you can call the Internet, such as IP phones, Huawei mobile phones also have a smooth call function, it is estimated that it is also a type of IP phone, I have experienced, the video is very clear, if all mobile phones have a smooth call function, I do n’t know Will it squeeze WeChat, QQ video business.
The above content is personally understood. If there is a mistake, please discuss and correct it!
