Directed diffusion is a prominent example of data-centric routing based on application layer data and purely local interactions. In its functioning it relies heavily...

Abstract. Ad hoc routing protocols that use broadcast for route discovery may be inefficient if the path between any source-destination pair is frequently broken. We propose and evaluate a simple mechanism that allows fast route repair in on demand ad hoc routing protocols. We apply our proposal to the Ad hoc On-demand Distance Vector (AODV) routing protocol. The proposed system is based on the Controlled Flooding (CF) framework, where alternative routes are established around the main original path between source-destination pairs. With alternative routing, data packets are forwarded through a secondary path without requiring the source to re-flood the whole network, as may be the case in AODV. We are interested in one-level alternative routing. We show that our proposal reduces the connection disruption probability as well as the frequency of broadcasts.

Ad hoc wireless networks are growing in popularity and usefulness, however they rely on broadcasting as a fundamental process for routing. Improvements to broadcasting have made ad hoc networks more feasible, but sometimes benefit only specific situations. Delayed Intelligence (DI) is proposed as a new load balancing approach where small delays are introduced to allow distributed responsibility delegation. Preliminary results show delayed intelligence, when applied in existing broadcasting methods such as passive clustering, can be used to improve the energy disparity and therefore extend ad hoc network lifetime.

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 Terms 1-hop clustering, algorithm/protocol design and analysis, message complexity, routing protocol, scalability, time complexity, wireless mobile ad hoc network. I.

Abstract In this paper we consider implementing efficient broadcasting of queries in a sensor network. In general, there are certain nodes in the network that do not need to broadcast in order for all nodes to hear the query. The primary task is therefore to identify these nodes. We propose a heuristical, distributed algorithm whereby the nodes rely on local information to make the decision. We then compare the performance of our distributed algorithm with a clustering algorithm, as well as a heuristical algorithm using global information, and show that it performs well. Key words: sensor networks, efficient broadcasts 1 Introduction Sensor nodes are physically small, and when fitted with various sensors such as digital thermometers as well as some means of wireless communications, can form a sensing network. These properties allow the sensor networks to be easily deployed in all types of environments, and we expect such networks to become ubiquitous in the near future. However, having a small form factor and being distributed without a connection to any steady power source means that the sensors have limited power, prompting many researchers to produce various algorithms that attempt to minimize usage of resources. Such algorithms are often closely related and tailored to the applications that use them. A query for data from the network originates from a root node, and this query is flooded throughout the network, i.e. all nodes broadcast the query once they receive their neighbors ' broadcasts. A simple example of such a query is given in Figure 1. In the figure, we see that the optimal set of nodes that should broadcast the message consists of nodes root and B only, thus not all the nodes need to broadcast. For this example, we call the nodes that do not need to broadcast (i.e. nodes A and C) redundant nodes.

Ad hoc wireless networks are growing in popularity and usefulness, however they rely on broadcasting as a fundamental process for routing. Improvements to broadcasting have made ad hoc networks more feasible, but sometimes benefit only specific situations. A history and comparison of broadcasting implementations will be explored, as well as how they relate to some key ad hoc on-demand routing protocols for implementation in a defined first responder scenario. After an exploration and comparison of existing methods, the benefits of specific broadcasting and routing advances will be combined to propose a novel ad hoc routing protocol. The proposed protocol will be an area for future research.

The EYES project (IST-2001-34734) is a three years European research project on self-organizing and collaborative energy-efficient sensor networks. It will address the convergence of distributed information processing, wireless communications, and mobile computing. The goal of