Cluster overlay broadcast (COB): MANET routing with complexity polynomial in source-destination distance

Abstract

Routing algorithms with time and message complexities that are provably low and independent of the total number of nodes in the network are essential for the design and operation of very large scale wireless mobile ad hoc networks (MANETs). In this paper we develop and analyze Cluster Overlay Broadcast (COB), a low-complexity routing algorithm for MANETs. COB runs on top of a 1-hop cluster cover of the network, which can be created and maintained using, for instance, the Least Cluster Change (LCC) algorithm. We formally prove that the LCC algorithm maintains a cluster cover with a constant density of cluster leaders with minimal update cost. COB discovers routes by flooding (broadcasting) route requests through the network of cluster leaders with a doubling radius technique. Building on the constant density property of the network of cluster leaders we formally prove that if there exists a route from a source to a destination node with a minimum hop count of ∆, then COB discovers a route with at most O(∆) hops from the source to the destination node in at most O(∆) time and by sending at most O(∆ 2 ) messages. We prove this result for arbitrary node distributions and mobility patterns and also show that COB adapts asymptotically optimally to the mobility of the nodes. In our simulation experiments we examine the network layer performance of COB, compare it with Dynamic Source Routing, and investigate the impact of the MAC layer on COB routing. Index Terms1-hop clustering, algorithm/protocol design and analysis, message complexity, routing protocol, scalability, time complexity, wireless mobile ad hoc network.

MANET Routing with Provably Low Complexity Through Constant Density Clustering and Route Request Broadcast

“…We have proven that the route discovery approach outlined in Section 4.1 finds a route with a hop distance that is linearly proportional to the shortest source-to-destination hop distance [9]. Note that this results holds even though we are employing long-range hops between cluster leaders in the route discovery and the transmission of the actual message.…”

“…We have proven that for this algorithm, the density of the overlay network of cluster leaders -i.e., the number of cluster leaders per unit area -is no higher than a constant, which is independent of the number of nodes or their distribution; specifically the cluster leader density is no higher than 4/π [9]. This result in turn can be used to show that a given cluster leader has no more than 49 other cluster leaders within its long transmission range.…”

“…The COB routing protocol [9] incorporates the efficient node clustering mechanism outlined in Section 3 and the efficient route discovery mechanism outlined in this section. These mechanisms are broadly applicable to MANET routing and can be incorporated in a wide range of MANET routing protocols.…”

“…In this paper, we give a tutorial overview of a recent line of algorithm-theoretic work [8,9] that has formally analyzed the elementary mechanisms of node clustering and route request broadcast for low-complexity MANET routing. More specifically, we explain how (i) node clustering with a specific constant density of cluster leaders (whereby density refers to the number of cluster leaders per unit area) that adapts optimally to node mobility can be combined with (ii) broadcasting of route requests over the network of cluster leaders with a doubling radius technique to achieve MANET route discovery with a complexity proportional to the distance between the source and destination node and independent of the overall network size.…”

“…More specifically, we explain how (i) node clustering with a specific constant density of cluster leaders (whereby density refers to the number of cluster leaders per unit area) that adapts optimally to node mobility can be combined with (ii) broadcasting of route requests over the network of cluster leaders with a doubling radius technique to achieve MANET route discovery with a complexity proportional to the distance between the source and destination node and independent of the overall network size. The Cluster Overlay Broadcast (COB) routing protocol [9] is build upon the combination of these two elementary mechanisms, which are broadly applicable in MANET routing.…”