基于原模图LDPC码的不等保护传输性能研究

摘要

Unequal error protection( UEP) is an important measurement regarding transportation of multimedia data. When the channel is in poor receiving condition, introduction of unequal error protection can effectively protect the more important transmitted data. In this paper, we make use of different performances of high and low bits of the constellation and combine protograph low density parity check (PLDPC) codes proposed by JPL which show better performances than conventional LDPC codes with pulse amplitude modulation (4PAM ) to realize the unequal error protection of transmitted data through AWGNC. We can get from simulation results that the BER performance of PLDPC codes is almost equal to that of regular LDPC codes when code length is small. The BER performances of PLDPC codes are more competitive than regular LDPC codes as the code length increases.%不等错误保护(unequal error protection,UEP)是多媒体数据传输的一个重要举措.在接收状态不理想的情况下,采用不等错误保护技术能够有效地保护传输过程中更重要的数据.利用星座图中信号点高低比特位的不同错误性能,将JPL(jet propulsion laboratory)实验室提出的易于实现且性能优异的原模图低密度奇偶校验码(protograph low density parity check,PLDPC)与四进制脉冲幅度调制(pulse amplitude modulation,4PAM)相结合实现在加性高斯白噪声信道(additive white Gaussian noise channel,AWGNC)下传输数据的不等保护.仿真结果表明,当码长较小时,原模图LDPC码与规则LDPC码不等保护性能相当,随着码长增长,原模图LDPC码的性能优于规则LDPC码.