On the Coexistence of Uncoordinated Ad-Hoc Networks

We consider a wireless communication model where a large number of transmitter-receiver pairs share a common Rayleigh fading channel without any coordination between them. The performance of a simple coexistence etiquette is analyzed in details, where packets are allowed to be transmitted from a given terminal only if the signal-to-interference-plus-noise ratio (SINR) at their intended receiver exceeds a given threshold, and transmission from that terminal is prohibited otherwise. Accurate interference models are developed assuming a large number of transmitter-receiver pairs that are randomly distributed according to a Poisson spatial point process. These are used to derive accurate expressions for packet error rates in the case of direct-sequence code division multiple access (CDMA) physical layer model and slotted packet transmission schemes. These results are then used to study the efficiency of this threshold-based coexistence etiquette and compare it with systems which are based on CDMA only.