Fading channel tracking properties of several adaptive algorithms for the Northern American Digital Cellular System

When maximum likelihood sequence estimation is used in a receiver for a time division multiple access (TDMA) mobile radio channel, the quality of fading channel tracking via different adaptive algorithms becomes very important. The concept of a tracking error filter, which is a key factor in calculating the mean square error for adaptive algorithms in the frequency domain, is introduced. Employing this analysis method, a new way is shown to prove the equivalence of the least mean squares algorithm and the exponential windowed recursive least squares algorithm. A general condition for the equivalence of the exponential windowed recursive least squares algorithm and the rectangular windowed recursive least squares algorithm is given, and the expression for the mean square error of the channel estimate is derived and the adaptive parameters are optimized