2,722 research outputs found
Bandwidth and Energy-Efficient Route Discovery for Noisy Mobile Ad-Hoc Networks
Broadcasting is used in on-demand routing protocols to discover routes in Mobile Ad-hoc Networks (MANETs). On-demand routing protocols, such as Ad-hoc On-demand Distance Vector (AODV) commonly employ pure flooding based broadcasting to discover new routes. In pure flooding, a route request (RREQ) packet is broadcast by the source node and each receiving node rebroadcasts it. This continues until the RREQ packet arrives at the destination node. Pure flooding generates excessive redundant routing traffic that may lead to the broadcast storm problem (BSP) and deteriorate the performance of MANETs significantly.
A number of probabilistic broadcasting schemes have been proposed in the literature to address BSP. However, these schemes do not consider thermal noise and interference which exist in real life MANETs, and therefore, do not perform well in real life MANETs. Real life MANETs are noisy and the communication is not error free.
This research argues that a broadcast scheme that considers the effects of thermal noise, co-channel interference, and node density in the neighbourhood simultaneously can reduce the broadcast storm problem and enhance the MANET performance. To achieve this, three investigations have been carried out: First, the effect of carrier sensing ranges on on-demand routing protocol such as AODV and their impact on interference; second, effects of thermal noise on on-demand routing protocols and third, evaluation of pure flooding and probabilistic broadcasting schemes under noisy and noiseless conditions. The findings of these investigations are exploited to propose a Channel Adaptive Probabilistic Broadcast (CAPB) scheme to disseminate RREQ packets efficiently.
The proposed CAPB scheme determines the probability of rebroadcasting RREQ packets on the fly according to the current Signal to Interference plus Noise Ratio (SINR) and node density in the neighbourhood. The proposed scheme and two related state of the art (SoA) schemes from the literature are implemented in the standard AODV to replace the pure flooding based broadcast scheme. Ns-2 simulation results show that the proposed CAPB scheme outperforms the other schemes in terms of routing overhead, average end-to-end delay, throughput and energy consumption
A modified IEEE 802.11 MAC for optimizing broadcasting in wireless audio networks
The use of network infrastructures to replace conventional professional audio systems is a rapidly increasing field which is expected to play an important role within the professional audio industry. Currently, the market is dominated by numerous proprietary protocols which does not allowing interoperability and does not promote the evolution on this sector. Recent standardization actions are intending to resolve this issue excluding however the use of wireless networks. Existing wireless networking technologies are considered unsuitable for supporting real-time audio networks, not because of lack of bandwidth but due to their inefficient congestion control mechanisms in broadcasting. In this paper, we propose an amendment of the IEEE 802.11 MAC that improves the performance of the standard when is used for real-time audio data delivery. The proposed amendment is based on two innovative ideas. First, it provides a protection mechanism for broadcasting and second, replaces the classic congestion control mechanism, based in random backoff, with an alternative traffic adaptive algorithm, designed to minimize collisions. The proposed MAC is able to operate as an alternative mode, allowing regular Wi-Fi networks to coexist and interoperate efficiently with audio networks, with the last ones being able to be deployed over existing wireless network infrastructures
Xcast Based Routing Protocol For Push To Talk Application In Mobile Ad Hoc Networks
Mobile ad-hoc networks comprise a type of wireless network that can be easily
created without the need for network infrastructure or administration. These
networks are organized and administered into temporary and dynamic network
topologies. Unfortunately, mobile ad-hoc networks suffer from some limitations
related to insufficient bandwidth. The proliferation of new IP Multimedia subsystem
services (IMs), such as Push-to-talk (PTT) applications consume large amounts of
bandwidth, resulting in degraded QoS performance of mobile ad-hoc networks. In
this thesis, a Priority XCAST based routing protocol (P-XCAST) is proposed for
mobile ad-hoc networks to minimize bandwidth consumption. P-XCAST is based on
demand route requests and route reply mechanisms for every destination in the PXCAST
layer. To build the network topology and fill up the route table for nodes,
the information in the route table is used to classify the XCAST list of destinations
according to similarities on their next hop. Furthermore, P-XCAST is merged with a
proposed Group Management algorithm to handle node mobility by classifying nodes
into two types: group head and member. The proposed protocol was tested using the
GloMoSim network simulator under different network scenarios to investigate
Quality of Service (QoS) performance network metrics. P-XCAST performance was
better by about 20% than those of other tested routing protocols by supporting of
group size up to twenty receivers with an acceptable QoS. Therefore, it can be
applied under different network scenarios (static or dynamic). In addition Link
throughput and average delay was calculated using queuing network model; as this
model is suitable for evaluating the IEEE 802.11 MAC that is used for push to talk applications. The analytical results for link throughput and average delay were used
to validate the simulated results
USING NS-2 COMPARISON OF GEOGRAPHICAL AND TOPOLOGICAL MULTICAST ROUTING PROTOCOLS ON WIRELESS AD HOC NETWORKS
Performance evaluation of geographical and topological multicast routing algorithms for cellular Wi-Fi ad-hoc networks is offered. Flooding and On-call for Multicast Routing Protocol (ODMRP) are simulated and in comparison with novels protocols: Topological Multicast Routing (ToMuRo) and Geographical Multicast Routing (GeMuRo) in pedestrian and vehicular situations. The situations evaluated recollect one multicast transmitter and one, two and three multicast receivers under numerous mobility and transmission levels. The conduct of 150 nodes is evaluated in terms of cease to end postpone (EED), jitter, packet delivery ratio, and overhead. Consequences display that ToMuRo is suitable for pedestrian eventualities because of its tree-based structure and GeMuRo is right for vehicular situations because its miles based on a mesh topology
Recommended from our members
Dynamic wireless mobile framework for distributed collaborative real-time information generation and control systems
Intelligent Transportation Systems (ITS) have only recently discovered the exciting possibilities in the nomadic and ubiquitous computing space to build a new generation of information systems by allowing the vehicle to act both as a carrier and consumer of wireless (and thus omnipresent) information. Wide deployment of such ITS systems may eventually allow for more dynamic and efficient transportation systems, which can contribute in several ways towards greater economic growth whilst respecting environmental sustainability. A great number of researchers have dedicated considerable time and resources to tackling traffic related issues by utilising the new wireless capabilities enabled by ITS; such initiatives cover a wide range of applications such as safety, knowledge sharing and infotainment. Indicative of the extent of such efforts is the plethora of research projects initiated by many national and multi-national organisations such as the EU Framework Programme for Research and Technological Development. To achieve their goals, proposed solutions from such organisations depend on the development and deployment of intelligent wireless mobile communication systems, where data dissemination issues make the prospect of efficient and effective communication a challenging proposition. Presently, Car-to-Car and Car-to-Infrastructure communications are two distinct avenues that make possible efficient and reliable delivery of messages via direct radio links in traffic areas. In all cases, high quality of communication performance is desirable for a communication system composed mostly of roaming participants; such a system needs to be dynamic, flexible and infrastructure-less. Consequently, Mobile Ad hoc Network (MANET)-based networks are a natural fit to ITS
- …