Maximum likelihood timing synchronizers for sampled PSK burst TDMA systems

A new maximum-likelihood (ML) symbol timing estimator for sampled, coherent, burst time division multiple access (TDMA), phase shift keyed (PSK) systems is derived. The estimator uses a periodic bit pattern for acquisition. The sufficient statistic turns out to be the ratio of the even and odd sample sums which is easily implementable digitally with much lower complexity as compared to previously proposed ML implementations. The performance of the new estimator is very close to the Cramer-Rao (CR) bound. It outperforms previously proposed sub-optimal estimators by about 2.0 dB and does not suffer from hangups, a common problem in all phase lock loop (PLL) based timing acquisition systems