An Adaptive BLAST Successive Interference Cancellation Method for High Data Rate Perfect Space-Time Coded MIMO Systems

Abstract

Linear dispersion (LD) based perfect space-time codes (STBCs) are an efficient means of increasing a multiple-input multiple-output (MIMO) system's overall diversity gain while maintaining the same spectral efficiency as a traditional spatial multiplexed (SM) MIMO system. Because the decoding procedure of LD codes traditionally requires the entire code to be received and decoded simultaneously, complexity increases proportional to the square of the MIMO array size. In this paper, we leverage the increased number of spatial and temporal layers at the decoder to dynamically reduce the complexity of a BLAST optimum ordering and successive interference cancellation (SIC) detector based on the instantaneous system capacity and data rate. The novel approach proposed in this paper is channel code and modulation agnostic, meaning the underlying constellation can be HEX or QAM and there is no feedback from a forward error correction (FEC) decoder, which makes the design useful in a wide range of MIMO systems employing LD codes with linear detectors. We investigate the method's bit error rate (BER) using MIMO dimensions up to $8 \times 8$ and bits per channel use (BPCU) up to 32. We analyze the system's run-time complexity and BER performance in software and implement perfect coding along with the novel method presented here in a custom MIMO orthogonal frequency division multiplexing (OFDM) system and test it over-the-air using an Ettus Research X310 software-defined radio (SDR) testbed.