The aim of this dissertation is to study the performance of distributed and opportunistic multi-channel bonding protocol in IEEE 802.11ac... Show moreThe aim of this dissertation is to study the performance of distributed and opportunistic multi-channel bonding protocol in IEEE 802.11ac WLANs, and design channel bonding strategies to efficiently utilize the available spectrum. To this end, we first develop an analytical framework to study the throughput performance of WLANs with co-existing ac users and legacy users, characterizing the contentions among ac and legacy users in both primary and secondary channels. By modeling the transmissions of legacy users and ac users with and without bonding as a twolevel renewal process, the channel bonding probability of ac users in each secondary channel can be derived. Based on the bonding probability, MAC throughput of ac and legacy users can be analyzed respectively. Our analysis show that in a homogeneous multi-channel WLAN where only ac users are present, the contention probability of ac users is the same as that in a single channel with the same number of users; and in a heterogeneous WLAN with both ac and legacy users, an ac user can achieve a higher throughput than a legacy user, although the overall throughput decreases due to the increased contention level imposed by ac users in secondary channels. Based on the analysis, we further propose a channel selection strategy for ac users to select the best primary channel, in order to mitigate the contentions in the network and attain the maximal throughput. Analytical results show that primary channel selection is indifferent in a homogeneous network, whereas in a heterogeneous network, ac users should select the least congested channel as the primary channel to attain the maximal throughput. To evaluate the performance of a multi-channel WLAN, we develop an event-driven simulator based on network simulator-3 (NS-3). Extensive simulations validate our analyses and the efficiency of the proposed channel selection strategy. M.S. in Electrical Engineering, December 2016 Show less
