Cooperative communications for sleep monitoring in wireless body area   networks
  This paper investigates the performance of cooperative receive diversity, for the wireless body area network (WBAN) radio channel, compliant with the IEEE 802.15.6 Standard, in the case of monitoring a sleeping person. Extensive WBAN measurements near the 2.4 GHz ISM band were used. Up to 7 dB and 20% improvement for two-hop communications with the use of relays are empirically demonstrated with respect to outage probability and outage duration, with 3-branch cooperative selection combining and 3-branch cooperative switch-and-examine combining. 
Samiya Shimly, Samaneh Movassaghi and David Smith
cs.OH