Contention Window based Parameter Selection to Improve Powerline MAC Efficiency for Large Number of Users

Power line based communication systems (PLC) are emerging as strong contenders in the home and personal environments. Their advantages of high data rates, no additional wiring and easy scalability make them very attractive for deployment in local area networks and broadband power line (BPL) Internet access. Effective use of the powerline bandwidth requires robust physical and medium access control (MAC) protocols to mitigate the harsh conditions of the powerline channel, as well as the capability to support prioritized multimedia traffic. Home Plug 1.0 is the most commonly used technology for powerline communication. HomePlug 1.0 uses carrier sense multiple access/collision avoidance (CSMA/CA) to provide a maximum MAC data rate of 8 Mbps. Just as in 802.11, the throughput performance of this scheme becomes critical when the number of users increases, as in BPL. In this paper, a modification in the medium access control protocol of Home Plug 1.0 is proposed, to make it a constant contention window based scheme. This modification is shown to significantly enhance the MAC performance under saturation conditions. An analytical and simulation framework is used to tune the modified protocol for best performance, under the assumption that the number of active stations is known or can be reliably estimated.