GMP-based Iterative Equalization in MIMO ISI Channels

In iterative equalization, the main problem to be solved is to gain the input information according to posterior probability density. To solve this problem, a generalized message passing algorithm is adopted, which can effectively perform channel estimation and obtain channel response information required for equalization. In MIMO receiving system, by designing an improved STBC frame structure, we can utilize the diversity gain brought by the system, and the receiving signal structure is convenient for calculation, and the performance of iterative reception can be improved. The detector includes a soft equalizer and a channel estimator, whose principle is similar to that of a soft equalizer and a soft decoder. It exchanges external information block by block according to an iterative algorithm, thereby improving the performance of the equalizer. By analyzing the performance of the algorithm, it is proposed to increase the semi-adaptive damping coefficient to ensure the independence of the equalizer and the interleaver. The results show that the performance of the improved algorithm is better than that of the receiver system without the improved STBC frame structure and without the GMP channel estimation algorithm in the MIMO receiving system.