Research On Topology Control Algorithms For Ad Hoc Network Lifetime

Wireless Ad hoc networks are decentralized and multi-hop networks. Ad hoc networks do not relay on a preexisting infrastructure. Minimal configuration and quick deployment make ad hoc networks suitable for emergency situations like natural disasters, civilian or military conflicts.While nodes in Ad hoc network are handheld devices, the battery of device is constrained. When energy is exhausted, it will impact on the performance and the lifetime of networks. So how to save the power consumption and lengthen the network lifetime are hot issues.In this dissertation, the topology control of Ad hoc networks is discussed. Without topology control, every node in the networks uses its maximal transmission power to communication. Therefore, the networks have high energy consumption and also a high interference. And retransmission because of the interference will increase the energy consumption. Therefore, the objective of topology control is to build proper topology by controlling node's transmission power to decrease energy consumption and communication interference, extend network lifetime. To achieve this objective, this paper proposes our topology control algorithm after reviewing some of the past algorithms.(1) By analysis of the characteristics of Ad hoc networks, we study the significance of topology control and research issues. This paper detailed introduces several representative topology control algorithms optimizing energy consumption and lifetime in Ad hoc networks, and analyzes weaknesses of algorithms.(2) Considering both transmit power and receive power, this paper proposes the energy model for wireless Ad hoc networks, which is more realistic. Based on the model, this paper analyzes factors which impact on network consumption and network lifetime by theory and experiment.(3) Nowadays, most focusing on energy topology control algorithms's aim is to get a topology which has minimum network consumption. But this topology could not maximum extend network lifetime. Based on the definition of the network lifetime, this paper gets the relationship of the network lifetime, the node's transmit range, electronics consumption. This paper proposes a distributed topology control algorithms, referred to as MLTC(Maximum Network Lifetime Topology Control). The topology graph which the algorithms generate has several nice properties: connectivity, less transmit range of per-node. Theoretical analysis and experimental results shows that MLTC can extend network lifetime.(4) Simulating correctly the process of node's energy consumption will most impact on right evaluation for energy consumption and lifetime in Ad hoc networks. This paper analyzes process of node's energy consumption in NS2 and introduces how to use Tcl language to implement the simulation. Based on the process of node's energy consumption, this paper add energy model to the MAC layer of OPNET. Experiment shows the model is effective.