452 research outputs found
Joint Head Selection and Airtime Allocation for Data Dissemination in Mobile Social Networks
Mobile social networks (MSNs) enable people with similar interests to
interact without Internet access. By forming a temporary group, users can
disseminate their data to other interested users in proximity with short-range
communication technologies. However, due to user mobility, airtime available
for users in the same group to disseminate data is limited. In addition, for
practical consideration, a star network topology among users in the group is
expected. For the former, unfair airtime allocation among the users will
undermine their willingness to participate in MSNs. For the latter, a group
head is required to connect other users. These two problems have to be properly
addressed to enable real implementation and adoption of MSNs. To this aim, we
propose a Nash bargaining-based joint head selection and airtime allocation
scheme for data dissemination within the group. Specifically, the bargaining
game of joint head selection and airtime allocation is first formulated. Then,
Nash bargaining solution (NBS) based optimization problems are proposed for a
homogeneous case and a more general heterogeneous case. For both cases, the
existence of solution to the optimization problem is proved, which guarantees
Pareto optimality and proportional fairness. Next, an algorithm, allowing
distributed implementation, for join head selection and airtime allocation is
introduced. Finally, numerical results are presented to evaluate the
performance, validate intuitions and derive insights of the proposed scheme
Design and analysis of a beacon-less routing protocol for large volume content dissemination in vehicular ad hoc networks
Largevolumecontentdisseminationispursuedbythegrowingnumberofhighquality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well
Previous hop routing: exploiting opportunism in VANETs
Routing in highly dynamic wireless networks such as Vehicular Ad-hoc Networks
(VANETs) is a challenging task due to frequent topology changes. Sustaining
a transmission path between peers in such network environment is difficult. In
this thesis, Previous Hop Routing (PHR) is poposed; an opportunistic forwarding
protocol exploiting previous hop information and distance to destination to
make the forwarding decision on a packet-by-packet basis. It is intended for use in
highly dynamic network where the life time of a hop-by-hop path between source
and destination nodes is short. Exploiting the broadcast nature of wireless communication
avoids the need to copy packets, and enables redundant paths to be
formed. To save network resources, especially under high network loads, PHR
employs probabilistic forwarding. The forwarding probability is calculated based
on the perceived network load as measured by the arrival rate at the network
interface. We evaluate PHR in an urban VANET environment using NS2 (for
network traffic) and SUMO (for vehicular movement) simulators, with scenarios
configured to re
ect real-world conditions. The simulation scenarios are configured
to use two velocity profiles i.e. Low and high velocity. The results show that the
PHR networks able to achieve best performance as measured by Packet Delivery
Ratio (PDR) and Drop Burst Length (DBL) compared to conventional routing
protocols in high velocity scenarios
From MANET to people-centric networking: Milestones and open research challenges
In this paper, we discuss the state of the art of (mobile) multi-hop ad hoc networking with the aim to present the current status of the research activities and identify the consolidated research areas, with limited research opportunities, and the hot and emerging research areas for which further research is required. We start by briefly discussing the MANET paradigm, and why the research on MANET protocols is now a cold research topic. Then we analyze the active research areas. Specifically, after discussing the wireless-network technologies, we analyze four successful ad hoc networking paradigms, mesh networks, opportunistic networks, vehicular networks, and sensor networks that emerged from the MANET world. We also present an emerging research direction in the multi-hop ad hoc networking field: people centric networking, triggered by the increasing penetration of the smartphones in everyday life, which is generating a people-centric revolution in computing and communications
- …