Features of four wireless extended Communication Technologies

The features of the four wireless extended communication technologies are completely explained. First, let everyone understand the features of the wireless extended communication technology, and then fully introduce the features of the wireless extended communication technology. It does not matter. After reading this article, you will certainly have a lot of GAINS, I hope this article will teach you more things.

The so-called spread-spectrum communication can be simply described as follows: it is an information transmission method, and its signal occupies a bandwidth far greater than the minimum bandwidth required for the transmitted information; the frequency band is extended by encoding and modulation, and has nothing to do with the transmitted information data. at the receiving end, the same Spread Spectrum Code is used for relevant Demodulation to deploy and restore the transmitted information data.

The Spread Spectrum Technology includes the following methods: direct sequence spectrum extension (DS for short), frequency hopping (FH), Time Hopping (TH), and linear frequency modulation (Chirp ). In addition, there are also combinations of these spread spectrum methods, such as FH/DS, TH/DS, and FH/TH. DS, FH, and FH/DS are widely used in communication.

Extended communication technology has the following features:

◆ Wireless extended communication technology features strong anti-interference capabilities

As the signal is extended to a wide frequency band, the relevant processing of the spread spectrum signal at the receiving end is called bandwidth compression, and the signal is restored to a narrow band signal. For interference signals, due to the absence of pseudo-random codes related to the spread spectrum, they are extended to a wide band, greatly reducing the interference power in the signal band, correspondingly, the output signal/Interference Ratio of the relevant device is increased, so it has a strong anti-interference capability. The anti-interference capability is proportional to the expansion of the frequency band. The wider the spectrum, the stronger the anti-interference capability.

◆ Extended wireless communication technology features multi-access communication

Spread Spectrum Communication is a type of multi-Access communication, called Spread Spectrum Multiple Access SSMA-Spread Spectrum Multipe Access), which is actually a type of Code Division Multiple Access (CDMA). Different Spread Spectrum codes are used to form different networks. Although the spread spectrum system occupies a wide frequency band, because each network can share the same frequency band at the same time, its spectrum utilization is even higher than that of a single carrier system. CDMA is a major multi-access communication method for personal communication in the future.

◆ Extended wireless communication technology features security and confidentiality

As the Spread Spectrum System expands the transmitted information to a wide frequency band, its power density decreases with the spread of the spectrum, and even the signal can be drowned in the noise. Therefore, it is highly confidential and it is very difficult to intercept, intercept, or intercept, or detect such signals unless the Spread Spectrum code used by the sender is used and synchronized with it for relevant detection, otherwise, the spread spectrum signal is powerless. Due to the low power spectral density of Spread Spectrum Signals, in many countries, such as the United States, Japan, Europe and other countries, as long as the power spectral density meets certain requirements, this band can be used without approval.

◆ Wireless extended communication technology features multi-path interference resistance

In mobile communication and indoor communication environments, multi-path interference is very serious. The system must have strong anti-interference capabilities to ensure smooth communication. In the features of the wireless extended communication technology, the Spread Spectrum Technology has a strong ability to resist multi-path interference. It uses the characteristics of the spread spectrum codes used by the spread spectrum, the multi-path energy can even be used to improve the system performance.