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Asynchronous digital communication system and method jointly frequencies and amplitudes of multiple sub-bands

A joint modulation and multi-subband technology, applied in multi-frequency code systems, baseband system components, shaping networks in transmitters/receivers, etc., can solve the problem that synchronous communication systems are not suitable for underwater communication environments and have large round-trip times And other issues

Inactive Publication Date: 2011-06-22
SOUTH CHINA UNIV OF TECH
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Problems solved by technology

In addition, the communication carrier of underwater acoustic communication—ultrasonic wave—transmits at a speed of 1500m / s in water, and medium and short-distance communication will generate a relatively large round-trip time, so the synchronous communication system is not suitable for underwater communication environments

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  • Asynchronous digital communication system and method jointly frequencies and amplitudes of multiple sub-bands
  • Asynchronous digital communication system and method jointly frequencies and amplitudes of multiple sub-bands
  • Asynchronous digital communication system and method jointly frequencies and amplitudes of multiple sub-bands

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Embodiment Construction

[0053] The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0054] Such as figure 1 As shown, the functional modules at the transmitter side of the asynchronous multi-subband communication system include: a symbol judgment module 101 , a transmission operation control module 102 , a carrier generation module 103 , a wireless transmission module 104 , and a frequency amplitude judgment storage module 105 . Corresponding to these functional modules is the structural diagram of the transmitter side of the asynchronous multi-subband communication system, as shown in figure 2 shown.

[0055] Such as figure 2 As shown, the transmitter side of the asynchronous multi-subband communication system includes a plurality of symbol judgment units 201, a transmission operation control unit 202, a plurality of carrier generation units 203, a...

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Abstract

The invention discloses an asynchronous digital communication system and method jointly modulating frequencies and amplitudes of multiple sub-bands. The method is as follows: dividing the band width of a communication channel into a sub-band or multiple sub-bands; and carrying out jointly asynchronous relative modulation of frequency and amplitude on each sub-band. The system comprises a transmitter and a receiver, multiple code element decision units of the transmitter are respectively connected with multiple input ends of a transmission and calculation control unit; multiple carrier generation units are connected between multiple output ends of the transmission and calculation control unit and the input ends of multiple wireless transmission units; frequency and amplitude storage units are respectively connected with the input ends of the multiple carrier generation units and the transmission and calculation control unit; and frequency and amplitude decision units are respectively connected with the frequency and amplitude storage units and the multiple input ends of the transmission and calculation control unit. In the invention, a direct digital frequency synthesis technology and a high-precision frequency estimation technology are combined through hardware, thereby taking full advantages of the technologies to realize high-reliable communication resisting Doppler frequency deviation and long time delay.

Description

technical field [0001] The invention relates to frequency and amplitude joint modulation in digital communication, in particular to an asynchronous multi-subband frequency and amplitude joint modulation and demodulation method that is resistant to Doppler frequency shift and long time delay. Background technique [0002] In a wireless communication system, when the sender or the receiver communicates in motion, the frequency of the signal received by the receiver will change, which is called the Doppler effect, which is a characteristic of any fluctuating process. [0003] The size of the Doppler frequency shift is one of the factors that reflect the change speed of the channel characteristics. The larger the Doppler frequency shift is, the faster the channel changes and the more serious the fast fading of the signal is. In the environment of large Doppler frequency shift, due to the rapid movement of the sender or receiver, the signal will produce significant frequency shif...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L25/02H04L25/03
Inventor 韦岗吴伟俊冯振华宁更新
Owner SOUTH CHINA UNIV OF TECH
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