| Multiple access protocols have great impact on wireless network performance. Researchers have conducted extensive studies considering the multiple access protocols in single-hop network scenarios (one tier). For many wireless systems, such as ad hoc and sensor networks, hierarchical network structures are utilized. In this dissertation, we investigate time division multiple access (TDMA) and Aloha-based multiple access protocols (including Carrier Sense Multiple Access (CSMA) protocol), with a focus on two-tier protocols, for the hierarchical networks (with multiple clusters). We study two-tier TDMA, two-tier slotted Aloha, TDMA-slotted Aloha as well as slotted Aloha-TDMA. For each type of the two-tier protocols, we consider Rayleigh fading and inter-cluster interference. For two-tier TDMA, we present analyses of throughput, average packet delay and dropping rate. We also extend the analysis to N-tier TDMA. For two-tier slotted Aloha, besides throughput and delay, we analyze the stability of the system. Following the approaches used to analyze two-tier TDMA and two-tier slotted Aloha, we also study hybrid protocol structures, TDMA-slotted Aloha and slotted Aloha-TDMA. In addition, we investigate the performance of the multiple access point (multi-AP) structure in which users have more than one AP to access. All analytical derivations and results are validated through simulations. |
