IEEE 802.15.4 Network Channel Access Optimization Strategy Research

As a short-range wireless communication standard,IEEE 802.15.4 protocol has been widely used in many military,industrial and medical applications.However,previous studies have shown that the IEEE 802.15.4 CSMA/CA with default parameter values suffers from a severe unreliability problem and thus results in additional energy cost.In order to address this problem,this dissertation proposes three schemes for different types of IEEE 802.15.4 networks as below:(1)For a single-packet reception(SPR)channel,we propose a lightweight distributed algorithm called Blind Adaptive Access Parameter Tuning(BADAPT)for reliable and energy-efficient communication without using the acknowledgement mechanism.We design an approach that allows the sensor nodes to obtain the reliability estimation merely relying on the local measurements in CCAs,and introduce a heuristic tuning algorithm that is triggered only when needed.Simulation results show that the BADAPT is effective both in stationary and dynamic scenarios.(2)Based on BADAPT,we further focus on how to autonomously adjust parameters for reliability guarantees with low energy consumption on a synchronous multi-packet reception(MPR)channel.We propose the reliability estimation method and a heuristic tuning algorithm grounded on this estimation.Simulation results verify that our scheme is effective and robust to different scenarios.(3)Following the asynchronous MPR assumption,we proposed an enhanced algorithm for IEEE 802.15.4 networks.Specifically,we allow a node to adopt a hierarchical transmission and backoff strategy according to its sensed number of concurrent packets.Simulation results demonstrate that the proposed mechanisms significantly enhance the throughput and reliability performance without extra energy cost.