Wireless Knowledge Charging Station: Graphical Multiple Access Technology
In a wireless communication system, multiple users simultaneously communicate with other users through the same base station, and different signals must be assigned to signals sent by different users and base stations. These features enable the base station to distinguish which of the user's mobile phones are transmitting signals from the signals transmitted by the plurality of mobile phones; each user's mobile phone can identify which one is the signal sent to itself in the signal sent by the base station. In wireless communication systems, addressing is performed using multiple access techniques.
1. Everything is done - Frequency Division Multiple Access (FDMA) technology
It is to let different earth communication stations occupy channels of different frequencies for communication. Since each user uses channels of different frequencies, there is no interference with each other. Early mobile communications used this technology.
2. Take turns to speak - Time Division Multiple Access (TDMA) technology
This multiple access technique allows a number of base stations to use one channel in common. However, the time taken is different, so there is no interference between them. Obviously, with the same number of channels, using time division multiple access can accommodate more users than frequency division multiple access. Most mobile communication systems today use this multiple access technology.
3. Deafness - Code Division Multiple Access (CDMA) technology
This multiple access technique is also used by multiple base stations in one channel. But each earth station is assigned a unique "code sequence" that is different from all other "code sequences", so each user does not interfere with each other. Because different "code sequences" are used to distinguish different earth stations, it is called "code division multiple access".
Using CDMA technology can accommodate more users than time division multiple access. This technology is more complicated, but it has been adopted by many mobile communication systems. In the third generation mobile communication system, wideband code division multiple access technology is also adopted. The ZWD series DTU is a typical module that uses code division multiple access. The module provides a fully transparent data channel, which can easily realize remote, wireless and networked communication methods. Make your device easy to connect wirelessly to the Internet.
The industrial embedded 3G module is embedded in the device to realize bidirectional high-speed transparent transmission of RS-232/485 and 3G networks. The maximum baud rate of the serial port is 921600bps. And use the graphical configuration interface, the device is equipped with a dedicated graphical configuration tool, that is, ready to use! Users do not need to understand complex TCP/IP, PPP and other protocols.
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