WiFi and LAA Coexistence: Improvements for WiFi's Performance
Aliasghar Keyhanian · 2017
As the demand for mobile data traffic increased significantly in the past few years, the Mobile Network Operators (MNOs) are considering different solutions to increase the network capacity.Since the licensed spectrum is scarce and expensive, deploying LTE in the unlicensed band can be a promising method to accommodate the market need for mobile data.However, LTE has to coexist with other heterogeneous network, especially WiFi, preexisting in the unlicensed medium.This coexistence can introduce a significant performance degradation for currently deployed WiFi networks.In this study, emphasis is given in analyzing the performance of WiFi and LTE coexistence scenario both analytically and through simulation.To this end, a number of solutions are proposed to increase the performance of WiFi.Firstly, a numerical analysis is performed to mathematically formulate the problem of coexistence between WiFi and LTE.Results show that LTE can outperform WiFi in terms of gaining access to the medium.Therefore, several modifications in the WiFi network have been studied (e.g.maximum packet length) to allow the WiFi network to achieve a fair share of the bandwidth while coexisting with LTE.The study is complemented with a heuristic approach that allows to efficiently calculate the payload length of WiFi packets.Specifically, the packet size is being determined on the fly according to the number of existing WiFi and LTE communicating devices.Finally, an alternative approach to compensate for the WiFi degradation in a coexistence scenario is proposed based on link adaptation.In particular, a number of enhancements in WiFi link adaptation is proposed to increase its adaptability in case of coexistence with LAA-LTE.First of all, I am thankful to the merciful God for helping me to begin, continue and finish my work.I would like to acknowledge the help and support of Dr. I. Lambadaris, my thesis supervisor, for guiding me in my research area and helping