Software architecture design,implementation, and evaluation of DCF-based MAC protocol on a low-power transceiver

The carrier-sensing multiple access with collision avoidance (CSMA/CA) protocol is the most well-known medium access control (MAC) protocol for wireless networks. Both the distributed coordination function (DCF) defined in IEEE 802.11 and the MAC layer defined in IEEE 802.15.4 are based on the CSMA/CA protocol. Nevertheless, these two standards have quite different carrier-sensing mechanisms. Different to continuous carrier sensing in DCF, an IEEE 802.15.4 node only senses the channel once just after a backoff. Sensing-once mechanism can reduce the computation loading on the CPU. However, it significantly increases the probability of failure transmission because a node is not fully aware of channel activity. This paper first proposes a software architecture integrating proper hardware features for designing a DCF-based MAC protocol and then successfully implements it on a low-power transceiver. In addition, this paper conducts experiments in a star topology network to compare the performance of the above DCF-MAC protocol with the IEEE 802.15.4 MAC protocol. Experimental results show that, without continuous sensing, the IEEE 802.15.4 network suffers a high transmission failure probability as the network size increases. Consequently, the proposed DCF-based MAC protocol outperforms the IEEE 802.15.4 MAC protocol in terms of packet loss probability and throughput.