George Neonakis Aggelou

Bio: George Neonakis Aggelou is an academic researcher from University of Surrey. The author has contributed to research in topics: Adaptive quality of service multi-hop routing & Ad hoc On-Demand Distance Vector Routing. The author has an hindex of 2, co-authored 3 publications receiving 181 citations.

RDMAR: a bandwidth-efficient routing protocol for mobile ad hoc networks

Abstract: We present a loop-free routing protocol for ad hoc mobile networks. The protocol is highly adaptive, efficient and scaleable; and is well-suited in large mobile networks whose rate of topological changes is moderate. A key concept in its design is that protocol reaction to link failures is typically localised to a very small region of the network near the change. This desirable behaviour is achieved through the use of a novel mechanism for route discovery, called Relative Distance Micro-discovery (RDM). The concept behind RDM is that a query flood can be localised by knowing the relative distance (RD) between two terminals. To accomplish this, every time a route search between the two terminals is triggered, an iterative algorithm calculates an estimate of their RD, given an average nodal mobility and information about the elapsed time since they last communicated and their previous RD. Based on the newly calculated RD, the query flood is then localised to a limited region of the network centred at the source node of the route discovery and with maximum propagation radius that equals to the estimated relative distance. This ability to localise query flooding into a limited area of the network serves to minimise routing overhead and overall network congestion. Simulation results illustrate its performance and demonstrate its good behaviour comparing to other protocols proposed by IETF Working Group. We refer to the protocol as the Relative Distance Micro-discovery Ad Hoc Routing (RDMAR) protocol.

A simulation analysis on reactive route repair techniques for QoS sensitive applications in mobile ad hoc networks

Abstract: One of the main challenges in mobile ad hoc networks (MANETs) is the routing of calls to mobile users moving frequently. The major tasks of routing are to find a route to a terminal quickly, a process often called ROUTE DISCOVERY, and to maintain and repair the active routes, a process often called ROUTE MAINTENANCE/REPAIR. ROUTE MAINTENANCE/REPAIR is a vital process as it deals with the salvage of calls when a link failure along a data route occurs. Data losses or failures in turn impact the end-to-end perceived quality of the application. In this paper we analyse through simulations various ROUTE REPAIR techniques tailored for operation in MANETS and demonstrate the effects of relative node velocity, node density and communication range on the communication cost and scalability of a routing protocol.

A review of routing protocols for mobile ad hoc networks

Abstract: The 1990s have seen a rapid growth of research interests in mobile ad hoc networking. The infrastructureless and the dynamic nature of these networks demands new set of networking strategies to be implemented in order to provide efficient end-to-end communication. This, along with the diverse application of these networks in many different scenarios such as battlefield and disaster recovery, have seen MANETs being researched by many different organisations and institutes. MANETs employ the traditional TCP/IP structure to provide end-to-end communication between nodes. However, due to their mobility and the limited resource in wireless networks, each layer in the TCP/IP model require redefinition or modifications to function efficiently in MANETs. One interesting research area in MANET is routing. Routing in the MANETs is a challenging task and has received a tremendous amount of attention from researches. This has led to development of many different routing protocols for MANETs, and each author of each proposed protocol argues that the strategy proposed provides an improvement over a number of different strategies considered in the literature for a given network scenario. Therefore, it is quite difficult to determine which protocols may perform best under a number of different network scenarios, such as increasing node density and traffic. In this paper, we provide an overview of a wide range of routing protocols proposed in the literature. We also provide a performance comparison of all routing protocols and suggest which protocols may perform best in large networks.

Age matters: efficient route discovery in mobile ad hoc networks using encounter ages

Abstract: We propose FResher Encounter SearcH (FRESH), a simple algorithm for efficient route discovery in mobile ad hoc networks. Nodes keep a record of their most recent encounter times with all other nodes. Instead of searching for the destination, the source node searches for any intermediate node that encountered the destination more recently than did the source node itself. The intermediate node then searches for a node that encountered the destination yet more recently, and the procedure iterates until the destination is reached. Therefore, FRESH replaces the single network-wide search of current proposals with a succession of smaller searches, resulting in a cheaper route discovery. Routes obtained are loop-free.The performance of such a scheme will depend on the nodes' mobility processes. Under standard mobility processes our simulations show that route discovery cost can be decreased by an order of magnitude, a significant gain given that route discovery is a major source of routing overhead in ad hoc networks.

A survey of QoS routing solutions for mobile ad hoc networks

Abstract: In mobile ad hoc networks (MANETs), the provision of quality of service (QoS) guarantees is much more challenging than in wireline networks, mainly due to node mobility, multihop communications, contention for channel access, and a lack of central coordination. QoS guarantees are required by most multimedia and other time- or error-sensitive applications. The difficulties in the provision of such guarantees have limited the usefulness of MANETs. However, in the last decade, much research attention has focused on providing QoS assurances in MANET protocols. The QoS routing protocol is an integral part of any QoS solution since its function is to ascertain which nodes, if any, are able to serve applications? requirements. Consequently, it also plays a crucial role in data session admission control. This document offers an up-to-date survey of most major contributions to the pool of QoS routing solutions for MANETs published in the period 1997?2006. We include a thorough overview of QoS routing metrics, resources, and factors affecting performance and classify the protocols found in the literature. We also summarize their operation and describe their interactions with the medium access control (MAC) protocol, where applicable. This provides the reader with insight into their differences and allows us to highlight trends in protocol design and identify areas for future research.

Scalability study of the ad hoc on-demand distance vector routing protocol

Abstract: As mobile networking continues to experience increasing popularity, the need to connect large numbers of wireless devices will become more prevalent. Many recent proposals for ad hoc routing have certain characteristics that may limit their scalability to large networks. This paper examines five different combinations of modifications that may be incorporated into virtually any on-demand protocol in order to improve its scalability. The scalability of current on-demand routing protocols is evaluated through the selection of a representative from this class of protocols. The performance of the un-modified on-demand protocol is compared against that of it combined with each of the scalability modifications. Each scheme's behavior is analyzed in networks as large as 10,000 nodes through detailed simulation. Based on the observations, conclusions are drawn as to the expected scalability improvement that can be achieved by each modification.