Unbalanced GTS Assignment Mechanism based on Delay Constraint in IEEE802.15.4

This article studied the GTS allocation mechanism of the IEEE802.15.4 protocol. Firstly, it discusses the existing deficiencies in the standard and studies the advantages and disadvantages of other improved algorithm. A mechanism is proposed in this paper breaking the original standard fixed GTS timeslot number firstly and making the time slot allocation more flexible. Secondly, it considers the demand that some nodes have special request for time delay and bandwidth, it analysis the constraints by using network calculus theory and tests nodes whether meet the allocation principle. Finally, it allocates the resources for nodes which meet the demand using their priority. Experiments show that this improved GTS allocation mechanism raises the time slot bandwidth utilization rate, satisfy the special requirements for some nodes, reduce the packet delay.