VCMA: Efficient channel access in wireless mesh networks using virtual coordinates

The Virtual Coordinate Multiple Access (VCMA) protocol is introduced and analyzed. VCMA is a medium access control protocol that defines transmissions schedules dynamically based on the assignment and exchange of virtual coordinates relative to an elected root node in a mesh network. VCMA is shown to attain feasible transmission schedules within a finite time, and its channel access delay properties are analyzed. The performance of the VCMA is compared with the performance of 802.11 DCF, which is a contention based MAC protocol; the five-phase reservation (FPRP) protocol, which is a schedule-based MAC protocol based on reserving time slots over fixed-length frames; and the node activation multiple access (NAMA) protocol, which is representative of distributed transmission scheduling based on probabilistic elections per slot. The performance comparison shows that VCMA attains much higher throughput than 802.11 DCF, FPRP or NAMA, and that it has lower variance in channel access intervals than contention-based schemes and schedule-based protocols based on probabilistic elections or reservations carried out in fixed-length frames.