Abstract: A method, system and computer program product for obtaining the reliability values for the hard decisions obtained by a Viterbi equalizer in a wireless communication system. A difference parameter is obtained for each Viterbi state at a stage while advancing the Viterbi trellis by the stage. The difference parameter for a Viterbi state at a stage is obtained by subtracting the path metric of the non-surviving path from the path metric of the surviving path for the Viterbi state at the stage. The difference parameter corresponding to the Viterbi state on the ML path at a stage is used as the reliability value for the hard decision obtained at L stages behind the stage, where L is the memory of the Viterbi trellis. A method for obtaining the accurate reliability values for the hard decisions corresponding to the last L stages of a truncated Viterbi trellis is also provided.

Abstract: A system, method and computer program product for detecting a frequency burst in a received signal at a wireless receiver is disclosed. The invention predicts the current sample of the received signal by filtering the past samples of the received signal through an adaptive filter. A prediction error is further obtained by subtracting the actual current sample and the predicted current sample. The prediction error is then used to adapt the adaptive filter. Since the frequency burst is a substantially predictable signal, the adaptive filter adapts to accurately predict the samples of the frequency burst. Therefore, the prediction error decreases when the frequency burst is received at the receiver. The end of the frequency burst is identified using the prediction error at each discrete time instant.

Abstract: A method and an apparatus for improving the equalization performance of a wireless receiver in the presence of co-channel interference by selectively filtering a received signal are disclosed. In the presence of co-channel interference, the noise in the received signal comprises a white noise component and a non-white noise component. Improvement in equalization is achieved by whitening the non-white noise component by selectively filtering the received signal. The selective filtering is governed by the dominant component of the noise in the received signal. The disclosed invention is suitable for use in Global System for Mobile Communications (GSM) wireless receivers using Gaussian Minimum Shift Keying (GMSK) signaling. The non-white noise component in the received signal, caused predominantly by co-channel interference, is whitened before feeding the received signal to Maximum Likelihood Sequence Estimator (MLSE), thereby improving the performance of MLSE.