摘要
在本文中针对频率选择性衰落信道提出了一种采用低密度校验(LDPC)码的多天线(MIMO)正交频分多址(OFDMA)系统。在这一多用户/多速率系统中,首先通过OFDMA消除用户之间的干扰,从而将多用户环境转化为单用户环境;然后通过联合MIMO软解调与LDPC码解码的Turbo迭代算法,消除发射天线之间的干扰并改善系统的性能。仿真结果表明,该方案可以有效地消除多用户干扰和发射天线之间的干扰,在通过利用空分复用以提高频谱效率的同时,也获得了由LDPC码提供的编码增益。由于该方案对于星座图没有任何限制,因此可以通过采用高效的调制方式进一步提高频谱效率。
A new multiuser/multirate transmission scheme for wide-band wireless mobile system is proposed in this paper. This scheme is LDPC coded MIMO OFDMA system to cope with frequency-selective multipath channel for multiuser communications. The two main principles of the proposed scheme are as follows., first, relying on OFDMA to eliminate multiuser interference and to convert multiuser environments to single-user ones; secondly, using joint LDPC decoding and MIMO soft-demodulating to eliminate interferences among transmit antennas and to improve performance. Simulation results show that the proposed system can effectively eliminate multiuser and multi-antenna interference, and is capable to increase spectral efficiency through multiplexing and to improve performance through LDPC coding. Furthermore, there are no restrictions on signal constellations in the proposed scheme, and thus spectral efficiency can be further increased by exploiting efficient modulation techniques like QAM, APSK.
出处
《计算机科学》
CSCD
北大核心
2007年第5期41-44,共4页
Computer Science
关键词
低密度校验码
多天线
正交频分多址
Low-density parity-check codes, Multi-input multi-output, Orthogonal frequency division multiplex access
