Spectral efficiency optimization with distributed beamforming in UWB based implant body area networks

In this paper, a distributed beamforming problem is investigated based on spectral efficiency (SE) optimization for ultra-wideband (UWB) based implant body area networks (IBANs). We consider a relay network consisting of one implant source, several wearable relays, and one body network coordinator under the assumption that the individual relay power is constrained due to the Federal Communications Commission (FCC) regulations for UWB signals. Taking into account realistic wireless channels and relay locations, the SE optimization problem is mathematically formulated and solved by using convex optimization. Simulation results show that the proposed beamforming scheme is superior to other transmission schemes. Moreover, our numerical examples reveal that the relay location has a significant impact on the beamforming performance and the proposed beamforming scheme provides an efficient way to prolong the lifetime of the implant node.