Prevention of collisions among two Wireless Personal Area Networks

With the increasing need for Wireless Personal Area Network (WPAN) technology to glue together various person-centric devices, the support for mobility and coexistence of these networks becomes crucial. Such support is of paramount importance in healthcare environments, where transmission collisions due to neighboring WPANs lead to degraded performance and loss/delay of transmitted critical data. In this paper we perform the theoretical analysis for collision occurrence between two close-range IEEE 802.15.4 WPANs, thus laying the grounds for collision prevention mechanisms. Specifically, we develop and state the necessary and sufficient conditions for collision to be prevented, as well as, compute the collision probabilities as function of Beacon Intervals. We show that collision is highly probable and that detection-restoration mechanisms do not mitigate and only postpone collisions. Finally, we propose initial guidelines for structural collision prevention as the only acceptable mechanism to guarantee performance and proper operations in safety critical mobile WPANs.