Multiple-Encoder Layered Space-Time-Frequency Architecture with QRM-MLD Detection

In this paper, in order to achieve the available spatial, temporal and frequency diversities, and also make the system implementation feasible for high speed orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) multiplexing, a novel LSTF transmitter architecture with multiple channel encoders is proposed with each independently coded information sub-stream being threaded in the three-dimensional (3-D) space-time-frequency transmission resource array. The performance of a receiver consisting of a maximum-likelihood detector with QR decomposition and M-algorithm (QRM-MLD) is exploited, by employing irregular low-density parity-check (LDPC) code as the channel code. The threaded distribution of each coded information sub-stream in the proposed LSTF makes it to achieve the spatial, temporal and frequency diversities the same as the conventional single-encoder LSTF where coding is applied across the whole information stream, and simulation results show that the performance of the proposed multiple-encoder LSTF architecture is very close to that of the conventional single-encoder LSTF. However, due to the use of multiple parallel encoders/decoders with a shorter codeword length, the proposed LSTF architecture has much lower hardware processing speed and complexity than the conventional LSTF.