MIMO Beamforming with Reduced Pilots and Radio Map for Emergency Wireless Communications

In large social gatherings or emergencies, the increasing communication demands can lead to congestion of the network, resulting in some user equipment (UE) being out of service. In such situations, it is crucial to provide emergency communication service to ensure reliable connectivity for all UEs. A key to this service is the rapid and accurate acquisition of channel state information (CSI) for beamforming, which is typically obtained by pilot-based methods. However, pilot-based methods may degrade seriously due to overhead and contamination. To address this issue, in this paper we consider reducing the pilot overhead and incorporating radio map to assist pilot-based beamforming. The prior location information provided by the radio map can reduce pilot overhead and help to counteract the loss caused by pilot contamination. According to the numerical simulations, beamforming with reduced pilots is superior to that with full pilots and can be further improved by integrating with the radio map.