De-spread method of direct sequence spread-spectrum signal

Abstract

This invention discloses a despreading spectrum method for direct sequence spreading spectrum signal, which contains selecting receiving mode to direct sequence spreading spectrum signal through multiple route index pattern outputted from multiple route index module to obtain the estimation value of information bit by adopting different receiver according to the time interval in multiple route index pattern and judging, said invention can reduce the total complexity of receiver, total power consumption and raise performance of total communication system.

Description

technical field [0001] The invention belongs to the technical field of communication, such as wireless communication, mobile communication, radar, electronic countermeasures, etc., and it particularly relates to a wireless mobile communication technology (such as WCDMA, cdma2000, TD-SCDMA, etc.). Background technique [0002] figure 1 The composition of the transmitter of the direct sequence spread spectrum signal is summarized without loss of generality: PN sequence generator module 1 , multiplier 2 , local carrier 3 , radio frequency processing 1 module 4 and transmitting antenna 5 . [0003] Transmitter working process: information bit b(t) passes through multiplier module 2 and spread spectrum sequence element α generated by PN sequence generator module 1 n Multiply (α n A chip duration of T c , the duration of one information bit is T, and T / T c =N, N is the processing gain of direct sequence spread spectrum, 1≤n≤N), the signal d(t) obtained after multiplication is...

AI Technical Summary

Problems solved by technology

[0010] (1) The above-mentioned first despreading method, the time domain direct sequence spread spectrum signal is directly despread in the time domain, and the multipath signal cannot be distinguished, the interference between the paths is large, and the effect of resisting the multipath fading and Doppler frequency shift of the channel is relatively weak. Difference;

[0011] (2) Although the RAKE despreading reception technology can utilize the energy of multipath signals, the number of resolvable paths is limited, the interference between paths is very large, and each branch needs to capture and track modules, so the system is too complicated;

[0012] (3) The method of equivalent despreading in the frequency domain of direct sequence spread spectrum signals in the time domain, the channel estimation is complex, the channel estimation is inaccurate, and the performance of the receiver is limited

And when the number of points N of the DFT operation is large, the requirements for the DFT chip are high, which increases the system overhead and increases the cost of the receiver.

[0013] (4) Time-domain direct sequence spread spectrum signal time-frequency two-dimensional equivalent despreading, which can reduce the influence of inter-path interference, and the time length corresponding to the signal processed by DFT operation can be controlled in a short period of time, improving The accuracy of channel estimation is improved, but when the delay between adjacent paths of the channel is large and the power attenuation of each path is not obvious or the root mean square delay of the channel is large, the time-frequency two-dimensional equivalent despreading needs Number of DFT (FFT) points N f Larger, relatively complicated to implement, unable to make full use of the energy of each path, and unfavorable for improving the bit error rate performance of the system

[0014] As far as the inventor knows, there is no method for despreading direct sequence spread spectrum signals by combining the advantages of any of the above two despreading techniques in the existing despreading receiving technology

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