IEEE 802.15.4 is one of the most prominent MAC protocol standard designed to achieve lowpower, low-cost, and low-rate wireless personal area networks. The contention access period of IEEE 802.15.4 employs carrier sense multiple access with collision avoidance (CSMA/CA) algorithm. A long random backoff time causes longer average delay, while a small one gives a high collision rate. In this paper, we propose an efficient backoff algorithm, called EBA-15.4MAC that enhances the performance of slotted CSMA/CA algorithm. 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 resolves the problem of access collision via the deployment of a novel Temporary Backoff (TB) and Next Temporary Backoff (NTB). In this case, the nodes not choose 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, the network simulator has been conducted. Simulation results demonstrate that the proposed scheme significantly improves the throughput, delivery ratio, power consumption and average delay.

networks, the range of backoff exponent is limited to very small values. Problem arises with increased probability of devices choosing the same number of backoff period (BPs). In return, this problem affects the channel utilization and packet collisions. In this paper, we proposed an efficient and adaptive backoff algorithm (EBA) to minimize the collisions among the contending nodes. While CSMA-CA delays for a limited number of backoff ranges, EBA is designed to enhance the performance of CSMA-CA by choosing the appropriate window size based on the collisions determined by the node. Furthermore, to increase the efficiency of EBA we split the backoff period into sub-backoff period called temporary backoff (TB) and next temporary backoff (NTB). During the implementation of EBA, the node choose the TB and NTB value randomly which is represent 10% to 50% of the actual backoff delay value instead of choosing backoff exponent (BE) randomly as in the standard. In this case, we decrease the probability of choosing the same number of backoff exponent randomly selected by nodes and minimize the probability of collision. Hence, we give better opportunities for successful packet transmissions. Simulation results demonstrated and compared the performance of EBA with that of IEEE 802.15.4 standard. According to the results obtained, EBA achieved better performance than the 802.15.4 standard in terms of throughput, delivery ration, and power consumption.