Efficient DOA tracking for TDMA-based SDMA mobile communications

In this paper, we discuss subspace tracking algorithms for DOA estimation that take a burst-wise data flow-as it naturally occurs in systems using a TDMA component-into account. This leads to a matrix model rather than to the well known snapshot vector model for the sensor array outputs. Unfortunately, many existing algorithms take advantage of the vector model and do either not support the matrix model or are not efficient with it. Therefore, we derive three efficient algorithms based on the matrix model which are extensions of the known ISU and PAST methods. Furthermore, we show how changes in the number of present signals can be detected and how to incorporate this step. Simulation results are presented