Design and Performance of LDPC Codes for OFDM Based Aeronautical Communication Systems

Abstract

With recent developments in forward error correction (FEC) schemes, low-density parity check (LDPC) codes are gaining more and more popularity with their performance approaching to near Shannon's limits. In this paper a flexible LDPC codec is designed and optimized for OFDM transceivers in aeronautical channels. We considered OFDM based aeronautical communication systems and investigated en-route and taxi scenarios. The basic aim was to achieve a targeted BER for the proposed OFDM system, despite channel impairments and high Doppler shift (aircraft traveling at twice the supersonic speed).Through simulations, performance was evaluated for best possible system configuration. Performance of both regular and irregular LDPC codes is evaluated as a function of code rate, column weight, number of decoder iterations, coding delay, number of cycles and block length. For OFDM system type of modulation, number of subcarriers and FFT size are used as metrics for performance evaluation.