Abstract:

To guarantee the transmission time constraints of group delay constrained services, a group delay constrained random medium access control algorithm for IEEE 802.15.4 was proposed based on Markov decision process (MDP). Different from the existing researches, the delay experienced by a group of packets instead of one single packet in a group was paid attentions. Also, the group delay constraints was used as quality of service indicators for the first time. In the algorithm, the medium access control layer parameters and decision threshold are estimated dynamically, and the optimal policy is used as a trade-off between the highest immediate rewards in the present and a possibly higher reward in the future. With the proposed algorithm, the terminal device will choose the best transmission strategy to overcome the channel congestion resulting from burst data. Simulation results show the efficiency of the proposed algorithm when the traffic load becomes heavy.

Key words: IEEE 802.15.4, Markov decision process, group delay constrained services, group delay constraints