Maximum likelihood sequence estimation based equalization within a mobile digital cellular receiver

In a digital communications receiver for receiving data transmitted sequentially over a channel in time slots, the transmitted data having values, a method of estimating the values of the sequentially transmitted data using sequential samples of the transmitted data as received over the channel within the time slots, the method comprising the steps of:

• storing the samples received during a time slot in a time sequential manner;
• estimating the location within the time slot at which a data value estimate error is most probable;
• processing the stored samples, starting with the first received sample in the time slot and proceeding in a forward direction with respect to the time sequence in which the samples were stored, beyond the estimated most probable error location, using a preselected maximum likelihood sequence estimation procedure to generate estimates of the values of the transmitted data;
• processing the stored samples, starting with the last received sample in the time slot and proceeding in a reverse direction with respect to the time sequence in which the samples were stored, beyond the estimated most probable error location, using the maximum likelihood sequence estimation procedure to generate estimates of the values of the transmitted data sequence;
• and
• processing the estimates of the preceding processing steps to generate enhanced estimates of the values of the transmitted data sequence.