Performance of FDE Using Partial LDPC Coding with Double Gray Mapping for Single-Carrier LOS-MIMO

Abstract

This paper presents the bit error rate (BER) performance of frequency domain equalization (FDE) using low-density parity-check (LDPC) coding for single-carrier line-of-sight (LOS)-multiple-input multiple-output (MIMO) multiplexing. We use partial LDPC coding with double Gray mapping and collaborative decoding, which is suitable for a high coding rate such as 0.9. Computer simulation results show that partial LDPC coding decreases the required received signal-to-noise power ratio (SNR) at the bit error rate (BER) of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> by approximately 1.0 dB compared to that for full LDPC coding for 256QAM in a Rummler fading channel. We show that the required received SNR at the BER of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> using partial LDPC coding is decreased by more than 6.6 dB compared to that without LDPC coding even for the deep notch depth of -20dB regardless of the relationship between the notch frequencies in the direct and cross links for 2×2 LOS-MIMO in a Rummler fading channel. Therefore, we conclude that FDE using partial LDPC coding with double Gray mapping and collaborative decoding is effective in achieving a low BER for single-carrier LOS-MIMO in microwave radio backhaul channels.