Improving the performance metrics of beacon enabled IEEE 802.15.4 using adaptive synchronization algorithm for reliable communication

This paper proposes an improvement for beacon enabled IEEE 802.15.4 medium access control (MAC) protocol for better energy consumption, reliability and synchronization among the sensors. First, we suggest an improved model over the existing beacon enabled IEEE 802.15.4. The modified IEEE 802.15.4 MAC protocol is modeled through a Markov chain using retry limits, acknowledgements and a new parameter namely `number of sleep slots´. Second, in beacon superframe structure there is an inactive period, which is used by sensors during sleep mode; the random sleep time for each sensor reduces the reliability of the network. We have proposed an optimized sleep time which divides the inactive period into number of slots in which the sensor utilizes a single slot in the sleep mode and then returns to the idle state. Third, sensors are synchronized by periodic transmission of beacon superframe from personal area network (PAN) coordinator. We have modified this by an adaptive synchronization method. We have simulated our suggested model in ns 2.34 to test the performance. The performance of our model is compared with the existing model for different performance metrics as reliability, data packet collision probability, data transmission failure probability and energy consumption of the sensors.