Patent ID: 6289061
Filing Date: 2001-09-11
Classification: H04B

Abstract:
In a wideband wireless communication system including mobile stations receiving communications from at least one base station, a method for providing automatic frequency control (AFC) to track the carrier frequency of communication signals received along a plurality of transmission paths, with corresponding Doppler frequency shifts, the method comprising the steps of:generating a reference signal having a reference frequency;combining received communication signals from each transmission path, whereby an average received communication signal is derived;in response to the reference signal and the received carrier signal for each transmission path, generating a first received signal for each transmission path;combining the first received signals and providing an average first received signal;in response to the average received communication signal, calculating the frequency error of the average received communication signal, whereby only a single frequency error computation is performed;in response to the frequency error calculated, changing the reference frequency, whereby the first frequency of each transmission path is corrected with a single error signal;comparing the signal to noise ratio of the first received signal of each transmission path with the signal to noise ratio of the average first received signal;in response to the difference between the signal to noise ratios calculated, calculating a weight for each transmission path; andin response to the weights calculated, variably adjusting the importance of each transmission path in the averaging of first received signals, whereby the signal to noise ratio of the combination of received signals is improved.