Simplified Turbo equalization algorithm

An algorithm and equalizer technology, applied in the direction of error correction/detection, digital transmission system, electrical components, etc. by combining multiple code structures, can solve problems such as high computational complexity, reduce complexity, and simplify computational complexity degrees, avoiding the effects of exponential and logarithmic operations

CN102185617AInactive Publication Date: 2011-09-14UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2011-09-14
Estimated Expiration
Not applicable · inactive patent

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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.
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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...

Examples

Embodiment Construction

[0016] The present invention is based on the fact that the variances of the transmitted symbols are all the same fixed value during the first iteration, and the coefficients of the equalizer are fixed at this time, and when the iteration reaches a certain number of times, the variance of the transmitted modulation symbols is very small. When the calculation of the coefficients of the equalizer has little relationship with the transmitted symbols, this part can be ignored, then we can think that the coefficients of the equalizer will not change once they are calculated. Therefore, it is possible to avoid performing a large-scale matrix inversion operation every time a symbol is calculated. In addition, when calculating bit soft information, the max-log decoding algorithm of Turbo code decoding can be used for reference, which can avoid exponential and logarithmic operations, thereby simplifying the computational complexity of the algorithm.

[0017] Technical scheme of the pres...