  In this paper, a cooperative two-hop communication scheme, together with
opportunistic relaying (OR), is applied within a mobile wireless body area
network (WBAN). Its effectiveness in interference mitigation is investigated in
a scenario where there are multiple closely-located networks. Due to a typical
WBAN's nature, no coordination is used among different WBANs. A suitable
time-division-multiple-access (TDMA) is adopted as both an intra-network and
also an inter-network access scheme. Extensive on-body and off-body channel
gain measurements are employed to gauge performance, which are overlaid to
simulate a realistic WBAN working environment. It is found that opportunistic
relaying is able to improve the signal-to-interference-and-noise ratio (SINR)
threshold value at outage probability of 10% by an average of 5 dB, and it is
also shown that it can reduce level crossing rate (LCR) significantly at a low
SINR threshold value. Furthermore, this scheme is more efficient when on-body
channels fade less slowly.
