Wi-Fi was originally designed to provide broadband wireless Internet access for devices which generate rather heavy streams. And Wi-Fi succeeded. The coming revolution of the Internet of Things with myriads of autonomous devices and machine type communications (MTC) traffic raises a question: can the Wi-Fi success story be repeated in the area of MTC? Started in 2010, IEEE 802.11 Task Group ah (TGah) has developed a draft amendment to the IEEE 802.11 standard, adapting Wi-Fi for MTC requirements. The performance of novel channel access enhancements in MTC scenarios can hardly be studied with models from Bianchi's clan, which typically assume that traffic load does not change with time. This paper contributes with a pioneer analytical approach to study Wi-Fi-based MTC, which can be used to investigate and customize many mechanisms developed by TGah.
The authors of @cite_7 study the power saving mechanism. They have developed a model, which allows estimating the average energy consumed by a STA and average time used by a STA to retrieve its data. As shown in , even though the model developed in @cite_7 can be used to find the average frame transmission time for a STA, it can not be used to find the correct time distribution required in problem A. Besides that, it can not be used at all to solve problem B.
@cite_7
1991290762
Communication is an enabling technology for the efficient control and management of next-generation Smart Grids. Energy conservation of the communication devices is essential for future large scale deployment of Smart Grid communication networks. However, existing power save protocols experience high contention in Smart Grid communication networks that have a large number of nodes and periodic traffic. We design a new energy conservation protocol, Power Save with Offset Listen Interval (PS-OLi), to address such contention problems. PS-OLi avoids message collisions by controlling the station wake up time with a calculated offset. A new analytical model is developed to characterize the power save performance of networks with periodic traffic. Simulation results show that our analytical model accurately predicts the collision probability and packet delay. We use our model to evaluate the energy efficiency of PS-OLi and standard power save protocols. Our results show that PS-OLi extends the lifetime of a Smart Grid communication network by more than 10 .