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为了降低正交频分复用(OFDM)系统中信道的时变导致的高误码平台,提出一种联合编码调制算法。该算法利用低密度校验码(LDPC)对删除信道的优良特性,将LDPC编码删余比特进行预编码,映射为零调制符号,辅助调制解调器减轻子载波间干扰(ICI)自干扰。仿真结果表明:与分离的编码调制相比,在相同传输速率条件下,该方法降低时变信道导致的LDPC误码平台达3个数量级以上。该联合编码调制算法可明显提高宽带无线通信系统在高速移动环境下的性能。
In order to reduce the high bit error rate caused by time-varying channels in OFDM systems, a joint coding and modulation algorithm is proposed. The algorithm uses the low-density parity-check-code (LDPC) to delete the excellent characteristics of the channel, pre-encodes the punctured bits of the LDPC code, maps to zero modulation symbols, and assists the modem to mitigate inter-carrier interference (ICI) self-interference. The simulation results show that the proposed method reduces the LDPC bit error rate caused by time-varying channel by more than three orders of magnitude compared with the separated coding modulation at the same transmission rate. The joint coding modulation algorithm can significantly improve the performance of broadband wireless communication system in high-speed mobile environment.