Beamforming for satellite communications in emergency situations

We consider a multi-beam Ka-band satellite communication system aimed at operating in emergency situations where terrestrial communications systems are no longer effective. In contrast to most systems which use one single beam to cover a large area, we study here the feasibility of a one beam per user concept, where a beamformer is calculated for each user. This should allow to guarantee the maximum antenna gain towards each user. We assess the performance of the minimum variance distortionless response (MVDR) beamformer and of a beamformer using a training sequence in realistic scenarios including channel, steering vector and synchronisation errors. We show that both beamformers provide a sufficiently high output signal to noise ratio in a DVB-RCS system. Copyright (C) 2008 John Wiley & Sons, Ltd.