Novel Construction and Optimization of LDPC Codes for NC-OFDM Cognitive Radio Systems

作者：Shebl Seif^*; Shokair Mona; Gomaa Ali

来源：Wireless Personal Communications, 2014, 79(1): 69-83.

DOI：10.1007/s11277-014-1841-9

• Cognitive Radio (CR)
• Random LDPC codes
• NC-OFDM
• BEC-R channel

In this paper, a random Low-Density Parity-Check (LDPC) code is proposed for Noncontiguous Orthogonal Frequency Division Multiplexing (NC-OFDM) Cognitive Radio (CR) systems. Unlike other encoding schemes which achieve a system code rate of only 1/4 when half of the subcarriers are active, the proposed scheme achieves a system code rate of 1/2. The LDPC code is used to enhance the data transmission rate. A new channel model comprised of a binary erasure channel concatenated with an uncorrelated fading channel and an AWGN channel is adopted for NC-OFDM CR systems. Moreover, the adopted channel model is employed with density evolution algorithm to obtain good degree distribution pairs for the LDPC code. Thereafter, a modified shortest-path algorithm is used to construct the parity-check matrix for the LDPC code. Simulation results show that the proposed LDPC code performs well in terms of both error rate and data transmission rate.

• 出版日期2014-11