Ehssan Sakhaee

Aeronautical ad hoc networks

There has been an enormous growth in mobile ad hoc networks (MANETs) in land based small to medium size networks with relatively strict power and resources. In this paper the concept of ad hoc networking between aircraft is introduced, which can be considered as a novel approach in increasing the data rate and practicality of future in-flight broadband Internet access. This method also reduces the Internet traffic load on satellite nodes and also propagation delay for real-time traffic transmissions, by effectively bypassing the satellite link for nonreal time data. A dynamic routing algorithm is also proposed for efficient routing in this kind of system. A new cost metric for increasing path duration is introduced to assist routing in the proposed ad hoc network

The Global In-Flight Internet

In this paper, the concept of a new form of mobile network formed in the sky is introduced, where the mobile routers are simply the commercial aircraft. This implementation aims to eliminate two main problems arising from the current in-flight broadband implementation. The first problem is the resource management issue that may arise from the rapid increase of in-flight broadband Internet use in the near future. This could consequently limit current satellite resources, and bandwidth. The other issue is the inherent problem associated with Internet use over satellite, such as the degraded performance of delay sensitive applications due to the long propagation delay of a satellite link. A system model for data access, stable clustering of aircraft, and efficient routing schemes are introduced, which are suitable for the aeronautical mobility model. Link stability is predicted by a novel approach using Doppler shift subjected to control packets to dynamically form stable clustering and routing protocols. Another aim of this paper is to show that relative velocity between nodes is adequate as a stability metric, dominating relative distance, and this becomes evident in the simulations presented. An outline of how the new system could potentially interact with the traditional Internet using Mobile IP is also briefly discussed

Stable Clustering and Communications in Pseudolinear Highly Mobile Ad Hoc Networks

Clustering of nodes provides an efficient means of establishing a hierarchical structure in mobile ad hoc networks. In this paper, we introduce two new stability-driven clustering algorithms for pseudolinear highly mobile ad hoc networks such as that of communication between aircraft, ships, trains, and cars on highways. The new algorithms aim at establishing stable clusters, where clusterhead reelection is reduced, and cluster membership periods are increased in the targeted system. The first algorithm is used for scenarios where the position information of nodes is not available, and the second algorithm is aimed at scenarios where position information is available [e.g., nodes are equipped with the Global Positioning System (GPS)]. The algorithms involve dynamic clusterhead election, and the scheme incorporates cluster maintenance to cater to changes in network topology as time progresses. Simulations show that the proposed clustering algorithms provide highly stable clusters with several advantages over previous one-hop clustering schemes.

Layered Attractor Selection for Clustering and Data Gathering in Wireless Sensor Networks

In this paper we propose a clustering and data gathering scheme for wireless sensor networks, based on a biologically-inspired approach that uses the concept of adaptive response by attractor selection as observed in a gene network. The approach uses a layered concept of clustering and routing that work independently, yet, resulting in an interdependent interaction via a common activity factor. This approach is aimed at establishing resilience and robustness in a two-layered protocol, where the network would perform a distributed clustering and routing of data to a sink. In this scheme, cluster heads are chosen according to their relative residual energy and routing is performed upon the relative cached data sizes and energy recharging rates of the next hop gateway nodes.

A New Stable Clustering Scheme for Pseudo-Linear Highly Mobile Ad Hoc Networks

The concept of clustering can provide an efficient means of establishing a hierarchical structure in large-scale mobile ad hoc networks. In this paper we introduce a new stability-driven clustering algorithm for pseudo-linear highly mobile ad hoc networks such as that of communication between aircraft, ships, trains and cars on highways. The new algorithm aims at establishing stable clusters, where clusterhead re-election is reduced, and cluster membership periods are increased in the targeted system. The scheme is suitable even in systems where global positioning systems (GPS) is not available. The algorithm involves dynamic clusterhead election. Simulations show that the proposed clustering algorithm provides highly stable clusters with several advantages over previous 1-hop clustering schemes.

Multipath Doppler Routing with QoS Support in Pseudo-linear Highly Mobile Ad Hoc Networks

Sustaining long link durations in highly mobile ad hoc networks presents a great challenge, mostly untreated in recent literature. In this paper we introduce a new routing algorithm based on the relative velocity of mobile nodes, which also incorporates Quality of Service (QoS), termed QoS Multipath Doppler Routing (QaS-MUDOR). The primary aim of QoS-MUBOR is to maintain long link durations, whilst meeting QoS constraints. The routing protocol proposed is based on data retrieval from nodes, where nodes act as content providers. This simulates scenarios such as downloading a file, a web page, or any form of data from other nodes which can provide it. We will show how utilizing the relative velocity of nodes using the Doppler shift subjected to packets assists in selecting stable paths, whilst maintaining the QoS requirements in highly mobile pseudo-linear systems such as an aeronautical ad hoc network.

Self-adaptive and mobility-aware path selection in mobile ad-hoc networks

In this paper we propose a protocol that uses mobility information and attractor-selection to effectively and adaptively establish stable communication in mobile ad hoc networks (MANETs). The aim of this approach is to not only establish stable durable communication paths between mobile entities, but also to create a resilient network which can quickly recover from unexpected changes in the network topology. In the proposed protocol, links will have longer lifetimes and break less frequently (as a result of mobility) and the established network will be more stable and resilient to sudden changes in network topology.

Aerouter/spl trade/ - a graphical simulation tool for routing in aeronautical systems

The enormous growth and demand for in-flight Internet access has driven the need for producing effective simulation tools in order to identify effectively the best resources, such as satellites and gateways, for routing in these large-scale systems. We introduce a simple simulation tool called Aerouter, which can assist in identifying the best satellites and gateways for routing in aeronautical applications. The proposed simulation tool includes new routing techniques and also takes Doppler and atmospheric attenuations into account in its automatic calculations. Preliminary results illustrate the effectiveness and usefulness of Aerouter for future in-flight Internet access networks.

A Transmission Range Reduction Scheme for Reducing Power Consumption in Clustered Wireless Sensor Networks

In this paper we propose a transmission range reduction scheme for a clustered wireless sensor network (WSN), in order to reduce power consumption while maintaining the network connectivity, particularly in scenarios where consecutive reporting of sensing values is inherent in the network. The platform WSN is based on a multi-hop clustering algorithm, where clusterheads send information to the sink via either gateway nodes or other clusterheads of intermediate clusters towards the sink. The main idea of this scheme is that the sink initially gathers the number of nodes or clusters in the network and instructs the reduction in the transmission range of the sensors until this number, hence connectivity is compromised. The proposed scheme does not require geographical information of nodes, and is independent of propagation model and environmental conditions that may cause non-uniform attenuation to radio signals. Furthermore, the scheme is independent of network topology, and can be applied to both uniform and non-uniform distribution of nodes. Simulation results show the effectiveness of the approach in two different clustering schemes, in regards to reducing energy consumption in the network.

Self-Organized Data-Energy-Aware Clustering and Routing for Wireless Sensor Networks

In this paper we propose a clustering and routingscheme for wireless sensor networks based on a self-organizing approach. The aim of thisapproach is for nodes to perform an integrated emergent task (data gathering and reporting to the sink) by simply following rules based on their individual local environment. Clusterhead election is also performed in a distributed manner and is based on sensorfs relative residual energy and the relative amount of information that they need to send to the sink. Hence nodes are assumed to possess variable data sizes across the network. In the scheme clusters are formed, and decide on their roles in the data gathering and routing procedure. Clusters at theedge of the network identify themselves and become in charge of initiating the routing of data, whilst intermediate clusters await data from higher clusters from the edge of the network for further aggregation and forwarding towards the sink. Simulation results show that the clustering scheme is able to reduce the total amount of energy used up by the network and efficiently routedata back to the sink.