The RCAP: a concept for robust beamforming and high resolution DOA tracking

Motivated by the objective of finding a reduced complexity implementation of the EM (estimate and maximize) algorithm, the authors move the concept of alternating projection (AP), reported Ziskind and Wax (1988), to a specific architecture for array processing in communications. Direction of arrivals (DOAs) are estimated by scanning the scenario with a dedicated beamvector, proving that low-resolution procedures with constraints, working in parallel, may enhance the performance of high resolution methods. Since no inverse is involved the method is robust and copes with full coherent sources (specular multipath) and fast updates. The procedure proved to be useful for adaptive beamforming in either point-to-point or mobile communications. Preserving the EM performance the array processing architecture offers a wide range of possibilities in updating and framing taking the best of hardware resources.