New media access protocols for wireless ad hoc networks based on cross-layer principles

摘要

We introduce two new medium access control (MAC) protocols for wireless ad hoc networks, the progressive backoff algorithm (PBOA) and the progressive ramp up algorithm (PRUA). Both protocols divide time in frames in which a contention slot is followed by a data slot. PBOA is integrated with a well known power control algorithm. PRUA performs no power control, and so is not as energy efficient, but can achieve a tight packing of transmissions by allowing nodes to make educated decisions during the contention period. Under both protocols, contenting nodes try to select their potential destinations so that spatial reuse is as high as possible, even if that means transmitting a packet that is not on the head of their routing buffer. We compare both protocols with carrier sense multiple access with collision avoidance (CSMA/CA), and also with the power control MAC (PCM) protocol. We also compare them with a hypothetical MAC protocol that would be able to make optimal decisions and so achieve the network capacity. We show that both protocols perform better than CSMA/CA and PCM in terms of throughput and robustness with respect to the choice of the routing protocol. Also, PRUA is more energy efficient than CSMA/CA, and PBOA is more energy efficient than both CSMA/CA and PCM. However, due to their distributed nature, our protocols still can not achieve the network capacity, even in simple network topologies.