Abstract: For the space-time-frequency block coding based orthogonal matrix can not get the full diversity gain, this paper proposes a novel space-time-frequency block coding scheme. The scheme utilizes Orthogonal Transform?Spreading Coding（OTSC） to achieve?the?full diversity gain by expansion?of ?data?symbols spatial?and frequency domain. And it applies to?MIMO-OFDM system with any?number of transmit antennas. The simulation results show that the BER performance of the system using this scheme is improved, also in low SNR for the system with any?number of transmit antennas.

Key words: space-time-frequency coding, MIMO-OFDM system, spreading code

摘要： 针对基于正交矩阵的空时频分组编码无法得到满分集增益的问题，提出了一种新的空时频分组编码方法，该方法利用正交变换扩展码（OTSC）对数据符号进行空域和频域的扩展，不仅能够实现满分集增益，且该扩展码适用于任意发射天线数下的MIMO-OFDM系统。仿真结果表明，利用该设计方案的系统误比特性能得到了提高，并且系统在任意收发天线数的低信噪比情况下也能获得良好的误比特性能。

关键词: 空时频编码, MIMO-OFDM系统, 扩展码