Wireless ad hoc network

About: Wireless ad hoc network is a research topic. Over the lifetime, 49048 publications have been published within this topic receiving 1172232 citations. The topic is also known as: ad hoc mode & WANET.

Using LIME to support replication for availability in mobile ad hoc networks

Abstract: Mobile ad hoc networks (MANETs) define a challenging computing scenario where access to resources is restrained by connectivity among hosts. Replication offers an opportunity to increase data availability beyond the span of transient connections. Unfortunately, standard replication techniques for wired environments mostly target improvements to fault-tolerance and access time, and in general are not well-suited to the dynamic environment defined by MANETs. In this paper we explore replication for mobility in the context of a veneer for lime, a Linda-based middleware for MANETs. This veneer puts into the hands of the application programmer control over what to replicate as well as a set of novel replication and consistency modes meaningful in mobile ad hoc networks. The entire replication veneer is built on top of the existing lime model and implementation, confirming their versatility.

A quantitative analysis of partitioning in mobile ad hoc networks

Abstract: The performance of distributed algorithms in mobile ad hoc networks (MANETs) is strongly influenced by the connectivity of the network. In cases where the connectivity is low, network partitioning occurs, e.g., due to node mobility. In this paper we introduce a set of metrics that describe several characteristics of partitioning in mobile ad hoc networks. We have conducted an extensive simulation study for a wide range of network scenarios to show the impact of node mobility, density and transmission range on the proposed metrics. We present some of the results we obtained, i.e., for the average number of partitions and the rate at which the partition in which an individual node is contained in changes.

Proactive address autoconfiguration and prefix continuity in IPv6 hybrid ad hoc networks

Abstract: In ad hoc networks (MANETs), wireless nodes spontaneously collaborate to route packets among a multi-hop and versatile topology. While such networks have originaly been considered as autarkical systems, it becomes clear that there is a growing interest in connecting them to the Internet. In such a hybrid ad hoc network, one or more nodes act as gateways to the outside world. This situation requires the use of a global addressing scheme in order to allow end-to-end communications between MANET nodes and correspondents in the Internet. In this paper, we present and evaluate an IPv6 address autoconfiguration protocol based on the original concept of prefix continuity. This feature ensures that there exists, between a node N and its gateway G, a path of nodes such that all nodes on this path use the same IPv6 prefix than N and G. As a result, all the nodes of a given sub-network form a logical tree rooted at the sub- network's gateway, and in which all nodes share an identical IPv6 prefix. In a multiple-gateways and multiple-prefixes environment, our protocol proactively and dynamically reacts to topological changes in order to maintain the prefix continuity of each sub- network.

Optimal SINR-based Random Access

Abstract: Random access protocols, such as Aloha, are commonly modeled in wireless ad-hoc networks by using the protocol model. However, it is well-known that the protocol model is not accurate and particularly it cannot account for aggregate interference from multiple interference sources. In this paper, we use the more accurate physical model, which is based on the signal-to-interference-plus-noise-ratio (SINR), to study optimization-based design in wireless random access systems, where the optimization variables are the transmission probabilities of the users. We focus on throughput maximization, fair resource allocation, and network utility maximization, and show that they entail non-convex optimization problems if the physical model is adopted. We propose two schemes to solve these problems. The first design is centralized and leads to the global optimal solution using a sum-of-squares technique. However, due to its complexity, this approach is only applicable to small-scale networks. The second design is distributed and leads to a close-to-optimal solution using the coordinate ascent method. This approach is applicable to medium-size and large-scale networks. Based on various simulations, we show that it is highly preferable to use the physical model for optimization-based random access design. In this regard, even a sub-optimal design based on the physical model can achieve a significantly better performance than an optimal design based on the inaccurate protocol model.

A Brownian Motion Model for Last Encounter Routing

Abstract: We use a mathematical model based on Brownian motion to analyze the performance of Last Encounter Routing (LER), a routing protocol for ad hoc networks. Our results show that, under our model, LER outperforms the simple flooding mechanism employed by reactive protocols.