在分布式残余频偏信道中,考虑多径瑞利衰落,针对采用判决反馈检测的两发射天线STBC-OFDM链路,提出了一种发射功率优化方法:根据平均信道功率增益、残余频偏方差以及噪声方差的大小,以最小化平均误比特率下界为目标,设置两分布发射天线的发射功率.仿真结果表明:相比于传统的各天线满功率发射方法,所提方法能够在节省发射功率的同时提高链路的误比特率性能.
We propose a transmit power optimization method for distributed transmit antenna space-time block coded orthogonal frequency division multiplexing(STBC-OFDM) systems in multipath Rayleigh fading channels with multiple residual frequency offsets(RFOs).We assume that the transmitter is equipped with two distributed transmit antennas and the receiver uses the decision-feedback detector.The proposed method is designed to minimize the lower bound of the average bit error ratio(BER) and the optimal transmit power for each transmit antenna is calculated according to the average channel power gains,the RFOs variance,and the noise variance.Simulation results show that the proposed method can save the transmit power while enhancing the BER performance compared with the conventional full power transmit method.