Research On Adjustable Topology Control Algorithms For Maximizing Ad Hoc Network Lifetime

The advancement of some scientific domains, including microelectronicstechnology, computer technology and wireless communication techniques and so on,gives an impulse to the generation and development of Ad Hoc networks. Ad Hocnetwork is a collection of devices that are equipped with wireless communicationcapabilities forming a multi-hop and self-organized wireless network, without theneed for a fixed infrastructure. With the merits of flexibility, fast networking and highdemanding of survivability and so on, it is applied to military affairs anddisaster-saving fields broadly. Each node in such a network typically operates onbatteries and is thus limited in its active lifetime. Even one node out of energy canhave important effect on network connectivity and performance. Therefore, in Ad Hocnetworks, maximizing the network lifetime under energy constrained network is acritical problem.In order to extend network lifetime, many algorithms in network layers havebeen proposed. As one of the most important techniques in Ad Hoc networks,topology control can be benefical to saving energies of nodes, prolonging the networklifetime and increasing network capacity. In this paper, the network topology controlalgorithm is discussed according to the characteristics of Ad Hoc network. In order toprolong network lifetime, we present an adjustable lifetime prolonging structure forAd Hoc networks to control topology. The research work focuses on the followingparts:(1) By summizing characteristics of wireless Ad Hoc networks and keytechniques, make sure the problem to be solved and the solution to be applied. Findthe drawbacks through the research on the existing approaches to topology controlwhich can prolong network lifetime and lay the foundation for the follow-up work.(2) Through the research found that the existing topology control algorithmsexist some drawkbacks as follows: First, most existing approaches to topology controlmainly considered to preserve minimum-energy paths in the resulting topologystructures which may not allow networks to realize maximum potential lifetime.Second, for most topology control algorithms, the energy model adopted is quiteunrealistic. When considering energy, only transmission energy is typicallyconsidered and the influence of different reception energy on underlying topologystructure is commonly neglected. Third, almost previous topologies have usually been constructed for the whole network in a static manner. As a result, network topologycan not be adjusted in response to changes of network dynamics. Hence, based on themore realistic energy model, considering both transmit power and receive power, inthis paper, we present an adjustable lifetime prolonging structure ALPS for wirelessAd Hoc networks. The topology deprived by ALPS is the minimum-power subgraphthat contains all the maximal lifetime paths between any pair of nodes. Unlike otheradjustable structures, this structure is adjustable in response to changes of receptionenergy consumption of wireless network interface. We show properties of ALPS byproof or simulation that it can effectively prolong network lifetime.(3) Based on ALPS, an adjustable lifetime prolonging structure ALPH isproposed for heterogeneous wireless sensor networks. It extends the idea of ALPSinto hybrid wireless networks and becomes more generalized. Theoretic analysis andexperiment results show that just like ALPS, the topology deprived by ALPH is theminimum-power subgraph that contains all the maximal lifetime paths between anypair of nodes and it can extend network lifetime remarkably.