Method and apparatus for detecting the sub-rate of a punctured data packet for a multi-rate transmission scheme

摘要

A method for detecting the transmission sub-rate of a data packet whose symbols are punctured prior to transmission as with an IS-95 transmission with a 13 kbps speech encoder. Sub-rates are detected by first regrouping the received symbols so as to exclude those symbols for which one or more of its repetitions were punctured. The regrouped symbols are then examined for consecutive identical soft decision symbols, i.e., the repetitive pattern used by the transmitter to mask the sub- rate, with statistical methods used to account for the effects of noise and power bit insertion. The repetitive pattern is then matched to the appropriate sub-rate.