Adaptive acquisition of DOA in space-time cochannel TDMA

A direction-of-arrival (DOA) acquisition algorithm is addressed for space-time TDMA signal processing. In our approach a generalized maximum likelihood ratio test (GLRT) is formulated to acquire frame synchronizations and DOA of cochannel TDMA bursts. The maximum likelihood estimators (MLEs) of DOA are derived with/without assumptions on the array geometry. The non-constrained MLE is used for acquiring frame synchronization, while the constrained MLE is applied to refine the DOA. To obtain the constrained MLE two algorithms are developed. One requires a 1-dimensional search and the other avoids the search with the ESPRIT algorithm. The performance of these proposed algorithms is illustrated in computer simulations using cochannel IS-54/136 signals.