Quasi OTDM transmitting method and system

Abstract

The disclosed QOTDM method and system comprise: connecting N continual signals with BHz bandwidth or corresponding sampling sequence into one continual signal to transmit in continual channel; converting the received signal on receive end into a composite zero-IF signal with orthogonal down-conversion and sampling digitalization, connecting frequency deviation by a carrier phase-locking loop; using frame-synchronization loop and adaptive channel balancer for high-precise sampling point synchronization and correction channel distortion; finally, recovering N signals. This invention has well performance for satellite communication system.

Description

technical field [0001] The invention belongs to the technical field of communication and relates to data transmission, specifically a punctual time division multiplexing transmission method and a communication system formed by the method, which are applied to digital communication. Background technique [0002] Orthogonal Time Division Multiplexing, OTDM for short is the same as Orthogonal Frequency Division Multiplexing, OFDM for short, see "OFDM Mobile Communication Technology and Application" published by People's Posts and Telecommunications Publishing House in 2003 Tong Xuejian, Luo Tao edited) a relatively dual information transmission technology. According to the Fourier transform time-frequency domain duality principle, a signal that is a square wave in the time domain has a spectral function in the frequency domain that is a Sinc function; conversely, a low-pass filter with ideal characteristics in the frequency domain, its The time domain impulse response is a Sin...

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Problems solved by technology

These two problems are: 1) If a higher frequency band efficiency is required, it requires that the overall channel characteristics accurately obey the first Nyquist criterion, and a slight deviation will introduce mutual crosstalk between channels and signal waveform distortion, Therefore, it is necessary to use a very good channel equalizer to compensate the channel to achieve this goal; 2) After the sample point sequence of N continuous signals is transmitted to the receiving end by sample point interleaving CWTDM, the receiving end is required to use a very high-precision Frame synchronization and sample point synchronization technology can make the signals of each channel completely separated, and a slight deviation will cause mutual leakage between sub-channels

Even as long as there is a deviation of 1% of the sampling interval in the position of the sampling point, there may be a leakage of nearly -40dB between sub-channels

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