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Jitter is used in wireless ad hoc networks to reduce the number of packet collisions and the number of transmissions. This is done by scheduling random back-off for each packet to be transmitted and by piggybacking multiple packets in a single transmission. This technique has been standardized by the IETF in RFC 5148. This paper investigates on the impact of the standardized jitter mechanism on network-wide...
Generally, IEEE 802.11 DCF is used as a MAC layer protocol to form an ad hoc network as it enables one to configure a mobile host either in ad hoc mode or infrastructure mode. In this paper, we carry out an analysis of IEEE 802.11 DCF for an ad hoc network under saturation conditions. We focus on the average end-to-end delay, throughput, and the loss probability for single hop as well as multiple...
To improve driving comfort and provide entertainment services, vehicular communication networks (VCNs) have appeared as an emerging solution, which consists of road-side units (RSUs) and on-board units (OBUs) to distribute multimedia contents. However, as most of OBUs always request the stored contents in the RSUs, how to update the contents in these RSUs when the original changes at its original...
Mobile ad hoc network especially follows multihopping mechanism for routing to make a path from source to destination. If we have a sound and solid routing path that would be efficient, reliable and adaptable to the different scenarios of network too by following the next hop mechanism and also should be the farthest node with in the cluster then we could achieve better performance by the network...
In this paper, we present a method for minimizing multi-hop transmission delay by optimally setting data rate along selected paths in Multi-hop Wireless Network (MHWN) based on multi-hop activity aware delay analysis. We develop an analytic model that enables us to obtain closed form expressions for delay in terms of multi-hop activity variables. A measuring deviation algorithm is used to derive the...
Mobile ad hoc network is a distributed wireless communication network, and energy issue has become a hot topic.CMMBCR considers the latest routing strategy about energy issue in ad hoc networks according to different situation , AOMDV multi-path routing protocol is improved based on the energy saving strategy CMMBCR.The improved protocol sets three node status and the nodes that do not work for a...
This paper develops a quite simple yet very accurate mathematical model for performance analysis of 802.11 ad hoc networks with traffic flow diversity (i.e., packet size and arrival rate diversity). The results show that 802.11 ad hoc networks can achieve very low packet delay and maximum throughput in non-saturated conditions. Furthermore, when the normalized total load is less than the critical...
The self-organised nature of Mobile Ad hoc Networks (MANETs) makes it a suitable candidate for rescuer communication in disaster scenarios. This paper presents a model basis for supporting the design of hybrid and adaptive routing protocols such as ChaMeLeon (CML). A size threshold point between proactive and reactive routing approaches is established using a probabilistic analytical model using dimensional...
In this paper we consider a cognitive radio network in a heterogeneous multi-channel scenario where channels are different in terms of achievable bit rates. Upon arrival licensed users (PUs) will occupy first the channels with higher achievable rates. As a result, secondary users (SUs) will see a set of channels which are different not only in their physical capacities but also in the activity profile...
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...
The emerging wireless vehicular communication technology is intended to improve safety and comfort of transportation systems. Different types of traffic information could be delivered through vehicle-to-vehicle and vehicle-to- infrastructure communications. This paper proposes a Quality-of-Service (QoS) supported multi-channel MAC scheme for Vehicular Ad Hoc Networks (VANETs), which can adaptively...
In this paper, we provide an analysis of the information propagation speed in bidirectional vehicular delay tolerant networks on highways. We show that a phase transition occurs concerning the information propagation speed, with respect to the vehicle densities in each direction of the highway. We prove that under a certain threshold, information propagates on average at vehicle speed, while above...
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,...
In delay tolerant network, message delivery can be inspired by biological communication models in realizing encountering and delivering. One way of communications can be through "thrown box" where the messages can be left and collected by different nodes in mimicking pheromone-based communications. In thrown box based model, the box is viewed as message relay and the delivery rate is enhanced...
In this paper, we address the relation between message delivery delay and reliability for the communication between a vehicle and a road side unit (RSU). We focus on sparse or low density vehicular ad hoc networks (VANETs), where timely message delivery and reliable transmission are of significant importance. We present an exact message delivery delay distribution for a two-lane road, where vehicles...
In this paper, we study the information propagation speed in a 1D mobile ad hoc network formed by vehicles Poissonly distributed on a highway and travelling in the same direction but with random Gaussianly-distributed speeds, independent between vehicles. Assume that time is divided into time slots of equal length and that each vehicle changes its speed at the beginning of each time slot, independent...
Recent advances in high-speed wireless LANs with physical layer (PHY) rates reaching 600Mbps make them ideal for multimedia applications. It has been shown that efficiency at medium access control (MAC) layer decreases with increasing the PHY rate. To achieve high efficiency, few researches have tried to use aggregation in which few packets are concatenated into a larger frame. The resultant frame...
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...
Delay tolerant networks (DTNs) can be composed of multiple heterogeneous groups (i.e., communities) of nodes. The nodes from these communities can cooperate with each other in order to carry and forward data packets so that the performance (e.g., delay) can be improved. However, this cooperation will incur additional cost on the nodes. In this paper, we first develop an analytical model to investigate...
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...
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