An efficient backoff algorithm for IEEE 802.15.4 with MAC techniques in slotted CSMA/CA networks

The IEEE 802.15.4 standard was proposed and has been commercially adapted as the protocol for the physical and data link layers. It is basically aimed for two devices communication and is viewed as promising for low-cost, low-ability and low data rate networks like Wireless Sensor Networks (WSNs).To avoid all nodes transmit at the same time, a commonly followed approach in (CSMA/CA) mechanism through which clients can compete with each other’s when accessing a channel, IEEE802.15.4 based devices shall wait for a randomly chosen back off period []120−−BEbefore they start emitting data. In this project, theefficient backoff algorithm, called EBA-15.4MAC that enhances the performance of slotted CSMA/CA algorithmis proposed. EBA-15.4MAC is designed based on two new techniques.Firstly, it updates the contention window size based on the probability of collision parameter. Secondly, EBA-15.4MAC resolved the problem of access collision via the deployment of a novel Temporary Backoff (TB) and Next Temporary Backoff (NTB). In this case, the nodes didnot choosethe backoff exponent randomly as mentioned in the standard but they select TB and NTB values which can be 10–50 % of the actual backoff delay selected by the node randomly. By using these two new methods, EBA-15.4MAC minimizes the level of collision since the probability of two nodes selecting the same backoff period will be low. To evaluate the performance of EBA-15.4MAC mechanism, extensive simulations is done using NS-2 simulation software. Simulation results demonstrate that the proposed scheme significantly improves the throughput, delivery ratio, power consumption and average delay