Energy-efficient, reliable wireless body area networks: Cooperative diversity switched combining with transmit power control

Cooperative diversity using switched combining, incorporating transmit power control (PC), is investigated for wireless body area networks (BANs). Outage probability and switching rate are derived from extensive empirical measurements, along with savings in circuit power consumption using simple 'sample-and-hold' PC in conjunction with switch-and-examine combining (SwC). Theoretical approximation of the switching rate gives a reasonable match with the empirical analysis. It is shown that transmit PC with SwC is an attractive method for increasing network lifetime, through reduced power usage, and for improving radio communications reliability in BANs.