TDS-OFDM系统中的差分空频发射分集方法

Differential space-frequency transmit diversity scheme for TDS-OFDM systems

在采用相干检测方法的发射分集方案中,进行信道估计需要付出很高的代价,为了降低接收端的实现复杂度,根据时域同步正交频分复用(TDS-OFDM)系统结构的特点,提出了差分空频发射分集及相应的非相干检测方法。该方法在时域进行差分编码,而在频域进行空频编码以获得分集增益。理论分析和仿真结果表明,尽管非相干检测方法损失了一定的接收性能,但无需进行信道估计,在慢衰落和快衰落信道中均能适用,是一种比较好的实现复杂度与接收性能之间的折衷方法。

Estimates of the channel state information are very costly in coherent transmit diversity schemes. To reduce the receiver complexity, a differential space frequency transmit diversity scheme was developed with a noncoherent detection method based on the frame structure of the time domain synchronous-orthogonal frequency division multiplexing （TDS-OFDM） system. The differential coding is performed in the time domain, while the space-frequency coding is processed in the frequency domain to achieve the diversity gain. Theoretical analyses and simulations show that the scheme works well in both slow and fast fading channels without channel estimates, with very little degradation of the bit-error-rate （BER） performance. The system is a good trade-off between realization complexity and system performance.