Simplified Turbo equalization algorithm

Abstract

The invention relates to a simplified Turbo equalization algorithm. The Turbo equalization is that: iterative decoding is executed by using a decoding theory of a Turbo code; a front-stage decoding structure of the Turbo code is substituted into a single input single output (SISO) equalizer; external information output by the equalizer is input into a decoder and decoded; and the decoded external information is fed to the front end for the iterative decoding. The invention provides an improved method by which the Turbo equalization calculation complexity is reduced. The fact is that: during iteration at the first time, all variances for sending symbols are the same fixed value, and a coefficient of the equalizer is constant; when the iteration frequency reaches a certain value, a variance for sending a modulation symbol is very small, and the calculation of the coefficient of the equalizer has little relation with the sent symbol, so the part can be ignored and the coefficient of the equalizer cannot be changed after being calculated; therefore, the problem that larger-scale matrix inversion calculation is performed once when the symbol is calculated once can be avoided. Moreover, during calculation of bit soft information, index number and logarithm calculation can be avoided according to a max-log decoding algorithm of decoding of the Turbo code; and the calculation complexity of the algorithm is reduced.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and relates to a Turbo equalization algorithm and its simplification. Background technique [0002] In mobile communication, due to factors such as refraction, reflection, and diffuse reflection, the transmitted signal will reach the receiving end from multiple directions with different amplitudes and different phases. This is the multipath effect. The wireless communication environment determines the existence of the multipath effect. The multipath effect causes the intersymbol interference of the signal. At the receiving end, multiple signals arriving on different paths at different times are superimposed together. The amplitude and phase angle of the received signal have changed, resulting in severe distortion of the signal. [0003] An equalizer is a receiver that can be used to compensate or reduce inter-symbol interference in a received signal. There are roughly the followi...

AI Technical Summary

Problems solved by technology

Although the above algorithms use the idea of ​​iterative decoding algorithm to greatly improve the system performance, the algorithm involves a large number of exponential and logarithmic operations, and there is also a large-scale matrix inversion

Therefore, the computational complexity of Turbo equalization is quite large

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