Simultaneous multiuser demodulation based on digital array processing

The use of antenna arrays to increase the efficiency of a communication link is studied. This work addresses a technique to solve the collision problem that takes place when various users ask simultaneously for access. It consists in a Time Reference Multi-beamformer/conformer system (TRM), which is implemented on a two-stage architecture. Taking advantage of the statistical independence of the impinging references and of the spatial diversity introduced by the array, the goal is the simultaneous demodulation of users, regardless their co-channel nature. The results show the increased system capacity for the specific case of a BPSK communication link. Other desirable features as robustness to calibration errors or good performance of the multiuser system both in adquisition and tracking are illustrated.