What is the principle of spread spectrum communication

Spread spectrum communication is an information transmission method, which is often used in military communications, mobile communications, satellite communications, and ranging and positioning. Whether in military or civilian use, spread-spectrum communication plays an important role. The further maturity of technology makes it more widely used, and the development trend is very good. In the next few years, it will make greater contributions to human society. So, what is the principle of spread spectrum communication and what are its advantages?

Features of spread spectrum communication

1. It is a digital transmission method.
2. Broadening of the bandwidth is achieved by modulating the transmitted information with a function that has nothing to do with the transmitted information (spread spectrum function).
3. Use the same spread spectrum function to demodulate the spread spectrum signal at the receiving end to restore the transmitted information.

Basic principles of spread spectrum communication

In terms of its modulation method, spread spectrum communication is no different from traditional data communication. It also includes ASK, FSK, PSK, and the recently rapidly developed QAM. The difference is that a spread spectrum processing link is added before modulation. The symbols to be transmitted are expanded with the signature code, and the expanded symbols are called chips; a despreading process is also added at the receiving end to restore N chips to one symbol.

Advantages of spread spectrum communication

(1) Spread spectrum communication has features such as message concealment, low probability of interception and anti-interference, and has great potential for military communications. Foreign military communications have been equipped with frequency hopping radios using HF, VHF and UHF frequency bands, and direct sequence spread spectrum radios have also begun to enter the practical stage.

(2) Using different predetermined spreading code (address code) sequences, code division multiple access (CDMA) and address-selective communication can be realized in the same frequency band, which can be used in satellite communication and indoor wired and wireless communication.

(3) The direct sequence spread spectrum signal has a high-resolution ranging capability independent of the distance, and is used in the Global Positioning System (GPS) and deep space exploration.

The above are the principles and advantages of spread-spectrum communication. Spread-spectrum communication has strong anti-interference, good concealment, and excellent performance characteristics, making it widely used in various fields. Looking at the history and status quo of spread spectrum communication, it can be expected that the development trend of spread spectrum communication is good, and it plays an important role in many applications.