Performance studies of a multi-band OFDM system using a simplified LDPC code

Ultra-wideband (UWB) is a promising radio technology for networks delivering extremely high data rates at short ranges. Multi-band orthogonal frequency division multiplexing (MB-OFDM) is a suitable solution to implement high speed data in ultra wideband spectrum by dividing the available spectrum into multiple bands. MB-OFDM achieves adaptability as well as high performance, low-power and low-cost characteristics through the usage of OFDM. Due to the importance of error correcting codes for OFDM systems, it is essential to employ a powerful error correcting code for the MB-OFDM system to improve the performance. Recently, low-density parity-check (LDPC) code has attracted great attention because it achieves bit error rate near to the Shannon limit. In this paper, we design and evaluate the performance of the MB-OFDM system using LDPC code. In order to simplify the implementation of the LDPC encoder and decoder, we introduce a joint code and decoder design approach to construct a class of (3, k)-regular LDPC code which exactly fits to a partly parallel decoder implementation. The simulations show that the performance of such a simplified LDPC coded MB-OFDM system is better than that of a convolutional coded MB-OFDM system, and is very close to that of the conventional LDPC coded MB-OFDM system. The implementation complexity of the simplified LDPC code is carefully examined subsequently in the paper.