TDMA based IEEE 802.15.4 for low latency deterministic networked control systems

In this paper, we propose a time division multiple access (TDMA) based protocol that works on slightly modified IEEE 802.15.4 network in star topology for low latency deterministic networked control systems. Each end device in network transmits its data frame after certain time delay in response to periodic request from network coordinator. This time delay is optimized for channel bandwidth utilization and reliable data frame exchange. While this TDMA based protocol eliminates the risk of frame collisions to great extent, MAC sub-layer modifications reduces the non-determinism of the network and increases its bandwidth efficiency. Experiments were conducted to evaluate the suggested protocol. Based upon these experiments results, the proposed protocol is a feasible solution for control systems with real time constraints.