Study of Adjustment Delay Scheme on IEEE 802.15.4 Networks at Beacon Enabled Mode

摘要

In the contention mechanism used to slotted carrier sense multiple access with collision avoidance (CSMA/CA) on IEEE 802.15.4 standard. Device nodes will perform a backoff process as soon as the clear channel assessment (CCA) detects as busy condition. The challenge of CSMA/CA as following: first, when the device nodes detect the channel in busy condition, the device nodes have to increase the value of backoff exponent (BE) which cause range of blind backoff process also increase. Second, when the device nodes detect the channel in busy condition, the device nodes have to increase number of backoff stage which cause more energy consumptions for entering next backoff stage. This article proposes a scheme to improve IEEE 802.15.4 medium access control, called adjustment delay scheme (ADES). ADES not only reduce probability of collision but also reduce probability of going to next backoff stage. The validity of study is proven by simulation experiments. ADES performs better than IEEE 802.15.4 standard in term of the probability of successful packet transmission, network goodput, bandwidth utilization as well as energy consumption in the networks