【摘要】 针对工作在时变深衰落,尤其是存在长时延、能量较强回波的信道环境下的接收机性能下降问题,提出一种在地面数字电视广播系统中使用的空频发射分集的解调方法。当使用传统正交逆矩阵进行空频解码时,需要假设正交频分复用(OFDM)系统中相邻子载波的信道频域响应相同,而这在衰落较强的信道环境下将不再成立。该文提出的空频解码方法无需上述假设,理论分析和计算机仿真的结果均证明,该方法能够有效提高系统在频率选择性较强的信道环境下的接收性能。更多还原

【Abstract】 The receiver performance degradation is a serious problem in time-variant,deep fading channels with high power echoes and long channel delay.A demodulation method for space frequency coded transmit diversity was developed based on the digital television terrestrial multimedia broadcasting(DTMB) system to solve the problem.The traditional space frequency decoder uses the orthogonal inverse matrix with the assumption that the adjacent sub-channel responses in the frequency domain are similar,which is no longer valid in deep fading channels.The proposed space frequency decoding method works without the assumption mentioned above.Both theoretical analysis and computer simulation show that the method can effectively improve the receiver performance in fading channels with strong frequency selectivity.更多还原