时变多径Rayleigh衰落信道中的匹配滤波界

Matched filter bound for time-varying multipath Rayleigh fading channels

通过将时变多径Rayleigh衰落信道中传输符号的判决变量表示为高斯随机矢量的二次形式,得出其特征函数以加权协方差矩阵之特征值为变量的解析表达式.因而该信道下的匹配滤波界可以简洁地表示为该特征函数部分分式展开中负特征值对应的系数之和.进一步比较了几种调制脉冲波形在时变多径Rayleigh衰落信道下的匹配滤波性能,发现矩形脉冲可以取得最好的时频分集.

By expressing the decision variables of transmission symbols in time-varying multipath Rayleigh fading channels as the Gaussian quadratic vector form, we derive the analytic expression for its characteristic function as a function of the eigenvalues of the weighted covariance matrix. Therefore, the matched filter bound for such channels can be expressed as the sum of the coefficients corresponding to the negative eigenvalues in the partial fraction expansion of the characteristic function. We further compare in matched filtering performance several modulation pulses in time-varying multipath Rayleigh fading channels, with the result that the rectangular pulse can achieve the best time and frequency diversity.