Performance evaluation of ISA100.11A industrial wireless network

The ISA100.11a standard defining wireless systems for industrial automation and control applications has been released by the international society of automation recently. ISA100.11a readopts the CSMA/CA mechanism of the original IEEE 802.15.4 for contention transmission purpose combined with TDMA-MAC scheme to provide deterministic services. This paper evaluates the performance limits of the CSMA/CA and TDMA mechanism of the ISA100.11a industrial wireless network. The evaluation is based on an accurate simulation model of ISA100.11a MAC and physical layer using OPNET modeler. Several sets of simulations with different network settings are conducted to study its various features, including the effects of 1) timeslot duration, 2) superframe period, and 3) maximum backoff exponent. The network throughput, average delay, and energy consumption/superframe are investigated as the performance metrics. It is demonstrated that ISA100.11a provides a maximum throughput about 35% and that the aforementioned parameter must be chosen carefully when designing ISA100.11a network based on network load in order to obtain the optimum performance of ISA100.11a.