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Recently the disconnected Delay-Tolerant Network (DTN) draws more and more attention.It is different from the traditional Ad-hoc and MANET. In DTN the disconnected nature and lack of end to end connectivity between nodes mean that the nodes communicate by the way of store-carry-forward. Therefore, it was rencently been recognized that mobility can be turn into a useful ally, by making nodes carry...
QoS support in MANETs is challenging because of unfavourable conditions such as a dynamic topology, limited bandwidth and energy constraints. In the past decade, significant effort has been devoted to QoS routing design which fails to obtain a one-for-all solution for MANETs. This reason, it is believed, is the application dependent nature of routing protocols. Moreover, few researchers consider the...
The rapid growth of wireless networks makes cognitive coexistence an important technology to use the spectrum efficiently. In this paper, a novel sensing based delay optimal method is considered to meet the requirement of the delay-sensitive traffics as well as to minimize the collision between the primary user and the secondary user. After establishing the Markov Decision Process (MDP) model, we...
Low control overhead and power cost are two key issues in wireless sensor networks to improve protocol efficiency. They decide the quality of service provided by the protocol. Ad-hoc On Demand Distance Vector protocol (AODV) is a preferred routing protocol in wireless sensor networks. The routing overhead of AODV is a drawback in power-constrained environment. This paper presents an enhanced routing...
The development and evaluation of Vehicular Ad Hoc Networks (VANET) and their applications is usually based on coupled simulation environments combining microscopic traffic models and packet level network simulations. However, it is difficult or rather impossible to build simulation scenarios where all the protocols, possible situations and various traffic conditions are properly modeled. This can...
In this paper performance modeling for a mobile stations operating according to CSMA/CA with binary exponential back-off (BEB) is discussed. Unlike the previous studies we concentrate on delay and loss performance metrics experienced by individual stations. To obtain delay distribution of an arbitrary packet we use Geo(i)/G(i)/1/K queuing system representing the number of stations having a frame for...
Supporting QoS for safety-critical applications for intelligent transportation systems accentuates the analytical modeling of delays in vehicular networks. Such analysis is, however, challenging due to the dynamics of such a network. We make progress by deriving lower- and upper-bounds for information dissemination delays in multi-hop vehicular networks using two different routing schemes. In particular,...
Providing a service with good quality for transmission and playing real-time voice conversations (voice streaming) over wireless ad-hoc networks is always a big challenge. Buffering and adjusting the playout time of packets is one of the methods used to overcome this challenge which can be deployed in receiver side. In this paper, a new adaptive playout adjustment algorithm to stream the voice conversations...
Delay tolerant networks (DTNs) are a kind of wireless mobile network which may lack continuous network connectivity. Multicast supports the distribution of data to a group of users, a service needed for many potential DTNs applications. While multicasting in the Internet and mobile ad hoc networks has been studied extensively, due to the unique characteristic of frequent partitioning in DTNs, multicasting...
End-to-end delay is critical for the real-time safety message delivery in Vehicular Ad Hoc Networks (VANETs). In this paper, we present an analytical model to evaluate the impact of transmission range on the end-to-end delay in 802.11p-based VANETs. Compared with the previous works, our model derives a concise expression of the transmission delay in saturated networks, and obtains the service rate...
In recent years, multi-channel MACs have attracted considerable attention in wireless networking research. Motivation for research into multi-channel MACs is their potential to increase the capacity of wireless ad hoc networks by exploiting multiple orthogonal frequency bands. This potential has been confirmed by several simulation studies that reported promising results for multi-channel MACs. However,...
Estimating the throughput of an WiFi connection can be quite complex, even when considering simplified scenarios. Indeed, the varying number of parameters specified in the standards makes it hard to understand their impact in terms of delay and throughput. The main contribution of this work is to present a simple scheme to compute the exact maximum throughput for an IEEE 802.11g network. The proposed...
Collusion Attack is an attack against Mobile Ad Hoc Networks and is based on Optimised Link State Routing (OLSR) Protocol. In this attack, two attacking nodes collude to prevent routes to a target node from being established in the network. Packet Delivery Ratio (PDR) of nodes 2-hops away from the victim drops to 0%. Multi Point Relay (MPR) selection process in OLSR is exploited to achieve route denial...
Congestion in mobile ad hoc networks not only results in transmission delay and packet loss, but also degrades throughput. For effective congestion detection and control, accurate estimation of MAC overhead, packet retransmission, backoff interval and queuing delay is necessary. This paper proposes a congestion aware nodes (CAN) based scheme to control congestion in mobile ad hoc networks. In this...
Wireless ad hoc networks are an emerging and popular technology to the world; however, the benefits of them are actually their fragility, too. Owing to mobile node movement, the link break problem always occurs in the network. The problem greatly influences the throughput, delay, jitter, and lots of performance issues of a routing protocol. Hence, this article is proposed to evaluate the influence...
We study the Minimal Delay Path (MDP) of message delivery and its evolving properties in social opportunistic networks where the connectivity is intermittent and evolving over time. Through in-depth analysis of the public released trace dataset from CRAWDAD community, our results show that the network connectivity is highly depended on some rare nodal contacts that occurred only few times rather than...
Guaranteeing quality of service is a key problem to multimedia stream in mobile Ad Hoc networks. The related works study the channel delay and bandwidth based on the MAC layer; however, there is little focus on queue delay. In a mobile environment, the changing of queue is quite different from those in static conditions. How to calculate the queue delay is a challenging question in mobile Ad Hoc networks...
One of the big fundamental issues in Bluetooth ad hoc network is its device discovery in network initialization which would effect the whole performance. The performance of short range wireless Bluetooth ad hoc network technologies depends on the promptness of its self-configuring procedures. Due to continuous inquiry and paging process, battery in Bluetooth-enabled devices is easily drained. This...
This paper presents and exercises a model to estimate the performance of Packet Loss Concealment (PLC) in wireless field environments. In particular, we estimate the probability of successfully receiving a random packet transmitted over an unreliable wireless link where a packet loss concealment algorithm such as the IETF's RFC 2198 standard schemes 1 and 2 are used. The model assumes a channel with...
One important challenge for broadcasting in mobile ad hoc networks is the well known broadcast storm problem. Most of existing techniques to prevent it usually lies in reducing the number of forwarding nodes in the process. One of these algorithms (from the state of the art) is the distance based broadcasting algorithm, that tries to minimize this number considering only as candidates of forwarding...
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