Patent ID: 7079601

Claim:
A method of estimating a transmission channel in a digital communications system which operates in accordance with GSM specifications, said communications system including a receiver which receives a signal transmitted over the transmission channel, said receiver including a channel estimation-based equalizer, said equalizer having a window size adapted to the actual delay spread of the transmission channel, and said equalizer using an estimate of the transmission channel for synchronizing and correcting said received signal, said received signal including a 26-symbol training sequence, said method comprising: estimating without matrix inversion, the transmission channel for different channel spans m, where 1≦m≦8, using at different synchronization points, the last m+15 consecutive symbols of the 26-symbol training seguence except for a group of symbols comprising the last four or fewer symbols: wherein tap values for different synchronization points and tap positions are obtained in a two-dimensional recursive computation step for joint optimization of synchronization and window sizing of the egualizer using Least Sguare Error (LSE) criterion; and wherein the tap values for different synch points are calculated in a 2-dimensional “north-west” direction.