Topology Control In Wireless Ad Hoc Networks

The progress of society is constantly urging the people's new demands on commu-nications. As these demands were met step by step, the accumulation of the science andtechnology of communications has made themselves develop faster and faster. The mostrevolutionary demand proposed in recent years is that, anyone can exchange any kind of in-formation with others anytime and anywhere, which means the dawning of Ubiquitous Age.In this situation, the wireless ad hoc network which is only for military utility years ago isintroduced to the masses.The wireless ad hoc network is a self-organized, peer-to-peer, multihop network withoutany fixed infrastructure. In most cases, it supports mobile communication. The propertiesof simplicity, fast deployment and strong survivability of the network make it capable ofextending the coverage of the traditional network effectively, and meeting the special ne-cessities in various situations, such as military affair, industry, business, medical treatment,home, office and etc.In this dissertation, the topology control of ad hoc networks is discussed. Without topol-ogy control, every node in the networks uses its maximal transmission power to communi-cate. Therefore, the networks have high energy consumption and also a high interference.Since nodes in ad hoc networks use battery power and meanwhile usually share communica-tion channel, energy consumption and signal interference become two of the most importantissues which have derived a lot of attentions. The objective of topology control is to buildproper topology by controlling node's transmission power to decrease energy consumptionand communication interference, extend network lifetime and improve network throughput.To achieve this objective, we propose our topology control algorithms after reviewing someof the past algorithms.The main contributions of our research include1. Proposing the energy model for wireless ad hoc network which is more realistic thanthe existing models, and based on the model, proposing several modifications to the past nearest-neighbor-based topology control algorithms. The simulation results showthat the modifications make the computed topology more power-efficient. (Refer toChapter 2 and Chapter 3)2. Proposing the local shortest-path-based topology control algorithms LSP and its im-provements LSPk and RLSP to decrease end-to-end communication energy consump-tion. Both theoretical analysis and simulation results prove that LSP and LSPk pre-serve the global shortest-path and have a low energy consumption, while RLSP ismore power-efficient than the former two algorithms. (Refer to Chapter 4, Chapter 5and Chapter 6)3. Proposing the algorithms IALMST and IBEC both of which take power and interfer-ence into account to avoid large interference in power-efficient topology. Both theoret-ical analysis and simulation results prove that both algorithms derive a proper tradeoffbetween energy efficiency and interference decreasing. (Refer to Chapter 7)4. Proposing the neighbor discovery scheme ASND which is adaptable to the networksituation. Simulation results illustrate that ASND can derive more accurate neighborinformation than FPSND and can detect link break faster. Meanwhile it can automati-cally adjust Hello interval according to the network situation to derive a proper tradeoffbetween saving energy and improving information correctness. (Refer to Chapter 8)...