In Ad-Hoc networks, the performance is significantly degraded as the size of the network grows. The network clustering by which the nodes are hierarchically organized on the basis of the proximity relieves this performance degradation. Finding the weakly connected dominating set (WCDS) is a promising approach for clustering the wireless Ad-Hoc networks. Finding the minimum WCDS in the unit disk graph is an NP-Hard problem, and a host of approximation algorithms have been proposed. In this paper, we first proposed a centralized approximation algorithm called DLA-CC based on distributed learning automata (DLA) for finding a near optimal solution to the minimum WCDS problem. Then, we propose a DLAbased clustering algorithm called DLA-DC for clustering the wireless Ad-Hoc networks. The proposed cluster formation algorithm is a distributed implementation of DLA-CC, in which the dominator nodes and their closed neighbors assume the role of the cluster-heads and cluster members, respectively. In this paper, we compute the worst case running time and message complexity of the clustering algorithm for finding a near optimal cluster-head set. We argue that by a proper choice of the learning rate of the clustering algorithm, a trade-off between the running time and message complexity of algorithm with the cluster-head set size (clustering optimality) can be made. The simulation results show the superiority of the proposed algorithms over the existing methods. KEYWORDS Wireless Ad-Hoc networks, clustering, weakly connected dominating set, distributed learning automata A wireless Ad-Hoc network is a multi hop wireless communication network supporting a collection of mobile hosts. There is no fixed infrastructure and no central administration and the mobile hosts can form a temporary network infrastructure in an Ad-Hoc fashion. Two hosts can directly communicate when they are within transmission range of each other, and indirectly through relaying by the intermediate hosts. In an Ad-Hoc network, each host assumes the role of a router and relays the packets toward the final destinations, if a source can not directly send the packets to a final destination due to the limitation of the radio transmission range. Since the wireless Ad-Hoc networks exhibit severe resource constraints such as the bandwidth and power limitations, network topology changes, and the lack of the fixed infrastructures and consequently,
In REF , two grouping algorithms were proposed to find the weakly connected dominating set (WCDS) for grouping the wireless ad hoc networks.
Clustering the wireless ad hoc networks: a distributed learning automata approach
J. PARALLEL DISTRIB. COMPUT
Computer Science