A Novel OFDM MIMO-Multiplexing Architecture with QRM-MLD Detection and LDPC Decoding

This paper is focused on the study of layered space-time-frequency (LSTF) architectures with channel coding for orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) multiplexing systems for high speed wireless communications over a frequency-selective fading channel. In order to achieve the available spatial, temporal and frequency diversities, and also make the system implementation feasible for high speed OFDM MIMO multiplexing, a novel LSTF architecture with multiple channel encoders is proposed with each independently coded layer being threaded in the three-dimensional (3-D) space-time-frequency transmission resource array. The maximum likelihood detection with QR decomposition and M-algorithm (QRM-MLD) is adopted. An irregular low-density parity-check (LDPC) code is chosen as the channel code. Simulation results show that the performance of the proposed multiple-encoders LSTF architecture is very close to that of the conventional single-encoder LSTF where coding is applied across the whole information stream. However, due to the use of multiple parallel encoders/decoders with a shorter codeword length, the proposed LSTF architecture is more suitable for high speed wireless communications.