Modeling the impact of deferred transmission in CSMA/CA algorithm for IEEE 802.15.4 using Markov chain model

IEEE has introduced the 802.15.4 standard for a low rate, low power, low complexity and short range Wireless Personal Area Network (WPAN) in 2003. The basic access mechanism used by the standard is the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). It has been noted that there is a problem of low throughput for short superframe duration due to the collision of the packets at the start of the superframe. Hence in 2006, the standard was revised and the CSMA/CA algorithm was modified such that deferred transmission was assigned another delay of random backoff periods before accessing the medium. In this paper, the effects of deferments on the performance of CSMA/CA have been analyzed, which has not been investigated in the past. An accurate analytical model for the deferred transmission in the CSMA/CA algorithm of IEEE 802.15.4/ 2006 using Markov chain has been developed. It has been found that the deferment of packets to a new superframe significantly affects the throughput for short frame duration.