Collision Free MAC Protocols for Wireless Ad Hoc Networks based on BIBD Architecture

Wireless Ad hoc networks represent a powerful telecommunication infrastructure that is being exploited for enabling general wireless networking connectivity for a variety of significant applications, e.g., military applications, industrial automation, sensor networks, vehicular networks, applications in case of disaster, etc. The distributed and flexible architecture of wireless ad hoc networks is a key factor, however, their wide deployment relies on protocols able to provide energetic optimization, high channel utilization, support for real time traffic, etc. In such a context, recently a Collision Free MAC protocol (CFMAC), based on the theory of Balanced Incomplete Block Design (BIBD), has been proposed. Its effectiveness has been already investigated showing significant improvements compared to the Standard IEEE 802.11, in terms of throughput, one -way packet delay, energy consumption and support of real time traffic. In this paper enhanced versions of CF-MAC have been considered with significant novelties regarding the introduction of variable time slot dimension, different management of Power Saving (PS) mechanisms, more efficient utilization of channel bandwidth, etc. The performance of these variants have been investigated by simple analytical models, in terms of energy saving, channel utilization, average access delay, etc., highlighting their improvements over basic CF-MAC protocol. In addition, computer simulations have been exploited to study the suitability of the proposed schemes to support VoIp applications.