2553 words - 10 pages

1. INTRODUCTION

A Mobile Ad hoc Network (MANET) is a self-configuring infrastructure less network of mobile devices connected by wireless. In a MANET each and every node is free to move in any direction, and hence change its links to other nodes frequently. All the nodes cooperatively maintain network connectivity without the aid of any fixed infrastructure units. Each node has a routing function whereby it communicates by forwarding packets via intermediate nodes. If two nodes are within the transmission range of each other, they communicate directly. Otherwise, other nodes are needed to forward their packets. MANET is characterized by non-restricted mobility and easy deployment, which makes them very promising.

It is known that the problem of QoS multicast routing with multiple QoS constraints is NP-complete. In the ﬁeld of artiﬁcial intelligence, genetic algorithm is a powerful tool to solve the NP-complete problem. Energy-efﬁcient Genetic Algorithm is used to ﬁnd the delay-constrained multicast tree and to reduce the total energy consumption of the tree. Thus reducing the power consumption of the nodes in the network and thereby prolonging the lifetime of the battery[1]. Choosing the energy consumption model plays an significant role in ad hoc network. Energy consumption models accounts for energy consumption due to data packets, control packets and retransmission. Different metrics based on power consumption of batteries at nodes are available. Such metrics ensures that the mean time to node failure is significantly increased. The remainder of this letter is organized as follows. Section II states problem description and Genetic Algorithm. Section III presents the proposed genetic algorithm and analyzes its convergence. The performance evaluation of the proposed algorithm done in Section IV. Section V concludes this paper.

2. PROBLEM FORMULATION AND GENETIC ALGORITHM .

2.1 NETWORK AND ENERGY CONSUMPTION MODEL

For a unit message transmission, the minimum energy needed by a link between nodes vi and vj is Pi,j = k1 (ri,j )β+k2,where ri,j Euclidean distance between vi and vj , k1 is a constant, β is the path loss exponent, and k2 is a constant that accounts for the overheads of electronics and digital processing. Each node in the network determine the distance between itself and its neighbor nodes. The connection of network is dependent on the transmission power of each node. Transmission power levels can be dynamically changed by each node. Every node vi in the network has two coverage areas: control coverage area (CRi ), data coverage area (DRi ). For transmission of control and data packets these coverage areas depends on the transmission power level selected by node vi. A MANET can be modeled as a graph G(V,E),where V = {v1,v2, ..., vn } is a set of nodes and E = {(i, j)|vi ,vj ∈ V } is a set of links. (i, j) . Each link (i, j) is associated with a distance li,j and a delay di,j. di,j is the data transmission delay between vi and vj ....

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