Development of an Optimum Beamforming Strategy for Outdoor Communication in Millimeter Wave Wireless Sensor Network

— The emerging future wireless sensor networks (WSNs) will utilize the millimeter-wave (mmWave) spectrum for wireless communication. The essence is to avoid spectrum crunch and mitigate bandwidth-hungry applications and services (traffic congestion) in WSNs by exploiting the underutilized spectrum between the 30 GHz and 300 GHz bands, respectively. Since mmWave has a short wavelength, deploying it in WSNs for remote monitoring applications in outdoor environments is still a challenge due to issues of shadowing, blockage effects, and propagation losses associated with atmospheric effects due to rain and oxygen. This paper proposed an optimum beamforming strategy to be employed in mmWave WSNs for remote monitoring applications to offset the additional propagation losses in mmWave outdoor environments through a two-split mix of analog beamforming and hybrid analog/digital beamforming. Also, signal transmission and reception through amplify-and-forward (AF) relay-assisted mmWave WSN is proposed for compensation of the signal fading effect due to blockages. This will ensure greater reliability in the 60 GHz underutilized unlicensed mmWave band when employed in mmWave WSNs for remote temperature monitoring in outdoor environments.