Minimizing Transmit-Power for Coherent Communications in Wireless Sensor Networks using Quantized Channel State Information

We consider minimizing average transmit-power with finite-rate feedback for coherent communications in a wireless sensor network (WSN). where sensors communicate with a fusion center (FC) using adaptive modulation and coding over a wireless fading channel. By viewing the coherent WSN setup as a distributed space-time multi-input single-output (MISO) system, we develop beamforming and resource allocation strategies and design optimal quantizers when the sensors only have available quantized (Q-) channel state information at the transmitters (CSIT) through a finite-rate feedback channel. Numerical results reveal that our novel design based on Q-CSIT yields significant power savings even for a small number of feedback bits.