Evaluation of the backoff procedure of Homeplug MAC vs. DCF

The standardized Medium Access Control (MAC) protocols for Power Line Communication (PLC) networks (Homeplug and IEEE 1901) are based on the Distributed Coordination Function (DCF) defined for IEEE 802.11. However, the backoff procedure is modified with the goal of decreasing the collision probability. In this work, the backoff procedure of PLC MAC protocols is compared to DCF in different traffic conditions and scenarios, including scenarios with all nodes in coverage range as well as topologies with hidden and exposed terminal problems. The goal is to demonstrate and quantify the pros and cons of each approach in each particular case. Results show that the modified backoff procedure of the Homeplug MAC reduces the collision probability when there is high contention. However, the performance is not always improved compared to DCF. Moreover, when Homeplug provides better performance than the vanilla DCF, we show that the DCF can be easily tuned to achieve similar gains.