An energy-efficient and traffic-aware CSMA/CA algorithm for LR-WPAN

In this paper, we propose an energy-efficient and traffic-aware CSMA/CA algorithm, referred to as ETCA, that aims to reduce redundant transmission of IEEE 802.15.4 Standard for Low-Rate Wireless Personal Area Networks (LR-WPAN). In Wireless Sensor Networks (WSNs), reducing energy consumption is one of the most important issues because it makes the network life-time longer. Sensor nodes consume most of energy for computing and transmitting operations [1]. Unlike IEEE 802.11, IEEE 802.15.4 MAC doesn't use Request To Send (RTS) and Clear To Send (CTS) frames, and it still has hidden terminal problems. Thus, if there are some hidden nodes, there are many collisions and retransmissions [2]. To reduce retransmission, we improve the carrier sensing features in MAC layer of IEEE 802.15.4. When the network is busy, the MAC detects it and adaptively chooses parameters of CSMA/CA mechanism to minimize collisions and the number of retransmission based on ETCA. We evaluated the proposed scheme with original 802.15.4 MAC on the ns-2 simulator. The results showed that our scheme outperforms the original by 15% in average when there is a retransmission activity.