Superposition Signal Input Decoding For Lattice Reduction-aided MIMO Receivers

SUMMARY This paper proposes a novel approach to low complexity soft input decoding for lattice reduction-aided MIMO receivers. The proposed approach feeds a soft input decoder with soft signals made from hard decision signals generated by using a lattice reduction-aided linear detector. The soft signal is a weighted-sum of some candidate vectors that are near by the hard decision signal coming out from the lattice reduction-aided linear detector. This paper proposes a technique to adjust the weight adapt to the channel for the higher transmission performance. Furthermore, we propose to introduce a coe ﬃ cient that is used for the weights in order to enhance the transmission performance. The transmission performance is evaluated in a 4 × 4 MIMO channel. When a linear MMSE ﬁlter or a serial interference canceller is used as the linear detector, the proposed technique achieves about 1 . 0 dB better transmission performance at the BER of 10 − 5 than the decoder fed with the hard decision signals. In addition, the low computational complexity of the proposed technique is quantitatively evaluated. words: