A Study of Connectivity in MIMO Fading Ad-Hoc Networks

We investigate the connectivity of fading wireless ad-hoc
networks with a pair of novel connectivity metrics. Our first metric
looks at the problem of connectivity relying on the outage capacity
of MIMO channels. Our second metric relies on a probabilistic
treatment of the symbol error rates for such channels. We
relate both capacity and symbol error rates to the characteristics
of the underlying communication system such as antenna configuration,
modulation, coding, and signal strength measured in terms
of signal-to-interference-noise-ratio. For each metric of connectivity,
we also provide a simplified treatment in the case of ergodic
fading channels. In each case, we assume a pair of nodes are connected
if their bi-directional measure of connectivity is better than
a given threshold. Our analysis relies on the central limit theorem
to approximate the distribution of the combined undesired signal
affecting each link of an ad-hoc network as Gaussian. Supported
by our simulation results, our analysis shows that (1) a measure of
connectivity purely based on signal strength is not capable of accurately
capturing the connectivity phenomenon, and (2) employing
multiple antenna mobile nodes improves the connectivity of fading
ad-hoc networks.