Signal demodulation method

Abstract

The invention discloses a signal demodulation method, which comprises the following steps of: positioning an intermediate code of a signal and extracting a signal of one time slot; carrying out channel estimation and joint detection on the extracted signal; and carrying out hard decision on data subjected to joint detection. The hard decision step particularly comprises the following steps of: dividing the data into symbol data in front of the intermediate code and symbol data behind the intermediate code according to the position of the intermediate code and carrying out reverse order arrangement on the symbol data in front of the intermediate code; carrying out phase compensation on the symbol data in front of the intermediate code, which is subjected to reverse order arrangement, one by one and carrying out hard decision on the compensated data, wherein a phase compensation value of first symbol data closest to the intermediate code is zero and phase compensation values of other data are respectively a phase-angle difference of the hard decision of previous symbol data and data obtained after the previous symbol data is subjected to phase compensation; carrying out the same treatment on the symbol data behind the intermediate code according to the treatment method of the symbol data in front of the intermediate code, which is subjected to reverse order arrangement; after carrying out reverse order arrangement on the symbol data in front of the intermediate code, combining the symbol data in front of the intermediate code, which is subjected to hard decision, with the symbol data behind the intermediate code, which is subjected to hard decision.

Description

technical field [0001] The invention relates to the field of communication technology, in particular to a signal demodulation method. Background technique [0002] In 3G (Third Generation, third generation) and B3G (Beyond Third Generation, super third generation) mobile communication systems, the coding technology uses QPSK (Quadrature Phase Shift Keying, quadrature phase shift keying), 16QAM ( QuadratureAmplitude Modulation, quadrature amplitude modulation) modulation method. Due to the existence of ISI (Inter-Singnals Interference, inter-symbol interference), MAI (Multi-Access Interference, multiple access interference) and frequency error (such as Doppler effect, the frequency error is not up to standard during the test) and other interference between signals , the performance of the communication system is limited. [0003] In order to improve the performance of the communication system, channel estimation and joint detection techniques are used to eliminate the ISI a...

AI Technical Summary

Problems solved by technology

[0004] However, after removing ISI and MAI interference through channel estimation and joint detection, there is still a linear deviation in the signal, which is the phase deviation caused by the frequency error

Due to the influence of Doppler frequency shift and local carrier error, the received data signal will have a slow frequency drift, which will cause the phase drift of the received data signal, which will have a bad impact on the communication system and degrade the system performance

Existing methods for eliminating frequency offset are very complicated, require a large amount of calculation and occupy a large amount of hardware resources

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