A Study on Bit Error Rate for Zero-Forcing THP MIMO Communication Systems Using QR Decomposition with Greedy Permutation

This paper discusses the theoretical average bit error rate (BER) of a multiple-input multiple-output (MIMO) communication system using zero-forcing Tomlinson-Harashima precoding (ZF-THP) with greedy replacement based QR de-composition (QRD). In the conventional ZF-THP with QRD, the probability distribution of each sub channel gain is known, and this information can be used to accurately calculate the theoretical average BER. On the other hand, in the case of the MIMO communication system using ZF-THP with greedy replacement (greedy ZF - THP), it is difficult to accurately deter-mine the probability distribution of the sub channel gains except for the first one, resulting in a non-negligible estimation error of the theoretical average BER. This paper proposes a new approximation of the probability distribution of each sub channel gain of the greedy ZF - THP, and shows that the proposed method gives sufficient estimation of the theoretical average BER.