Hakim Badis

QOLSR, QoS routing for ad hoc wireless networks using OLSR

This paper describes a novel quality-of-service (QoS) routing protocol for ad hoc networks based on the OLSR protocol. Our protocol, QOLSR, is designed for wireless networks with stationary or moving nodes, where each node is equipped with 802.11 wireless card. The goal of our protocol is not only to find a route from a source to a destination, but an optimal route that satisfies the end-to-end QoS requirement, often given in terms of bandwidth or delay. We present an analytical model to compute the average delay and permissible throughput on links using the IEEE 802.11 medium access protocol and considering correlations and interferences between nodes. This model takes into account packets collision probability, nodes MAC queuing and service times based on the IEEE 802.11 binary exponential backoff algorithm and the events underneath its operation. Afterwards, our protocol assigns weights to individual links based on the average delay and bandwidth metrics of packets over the link. We present a distributed algorithm for multiple QoS requirements to find the source destination optimal paths in terms of bandwidth and delay using the known partial network topology available on each node. However, these optimal paths in partial network topology are not optimal paths in the whole ad hoc network. We show that this problem is due to the heuristic for the selection of MPRs used in OLSR. We propose innovative heuristics for the selection of MPRs based on QoS measurements that allow QOLSR to find optimal paths on the known partial topology having the same bandwidth performances that those on the whole network. The performance evaluation of our protocol in both static and dynamic ad hoc networks is extensively investigated. Mathematical analysis and simulation results show that the QOLSR protocol yields better performance compared to the best-effort OLSR protocol and significantly improves throughput by using our proposed heuristic. Copyright

QoS for Ad hoc Networking Based on Multiple Metrics: Bandwidth and Delay

A link state routing approach makes available detailed information about the connectivity and the condition found in the network. OLSR protocol is an optimization over the classical link state protocol, tailored for mobile ad hoc networks. In this article, we design a QoS routing scheme over OLSR protocol, called QOLSR. In our proposal, we introduce more appropriate metrics than the hop distance used in OLSR. In order to improve quality requirements in routing information, delay and bandwidth measurements are applied. The implications of routing metrics on path computation are examined and the relational behind the selection of bandwidth and delay metrics are discussed. We first consider algorithms for single-metric approach, and then present a distributed algorithm for multiple metrics approach. We also present a scalable simulation model close to real operations in Ad Hoc Networks. The performance of our protocol are extensively investigated by simulation. Our results indicate that the attained gain by our proposal represent an important improvement in such mobile wireless networks.

A link-state QoS routing protocol for ad hoc networks

A quality-of-service (QoS) routing protocol is developed for mobile ad hoc networks. We perform the proposed QoS-based routing in the optimized link state routing (OLSR) protocol, introducing a more appropriate metric than the hop distance. In our simulations the QoS routing protocol produces better performance comparing with the best-effort OLSR protocol.

QOLSR multi-path routing for mobile ad hoc networks based on multiple metrics: bandwidth and delay

Research on multi-path routing protocols to provide improved throughput and resilience in comparison with single-path routing has been explored in detail in the context of wired networks. However, the multi-path routing mechanism has not been explored thoroughly in the domain of ad hoc networks. We propose the path selection criteria and QOLSR multi-path calculation based on bandwidth and delay. QOLSR is an extension to the single-path routing protocol known as the optimized link state routing (OLSR) protocol; it uses bandwidth and delay to satisfy end-to-end QoS requirements. The resulting protocol computes multiple loop-free and node-disjoint paths. The loop-free property is guaranteed by using the shortest-widest path algorithm. The node-disjoint property of multiple paths is achieved using our proposed algorithm. We also present an evaluation comparison of QOLSR multi-path routing against QOLSR single-path routing using a scalable simulation model.

QoS routing in ad hoc networks using QOLSR with no need of explicit reservation

Multimedia applications often require guaranteed quality of service (QoS) and resource reservation, which has raised a number of challenging technical issues for routing. We have proposed the QOLSR protocol, a QoS routing over OLSR protocol introducing metrics, such as bandwidth and delay, that are more appropriate than the hop distance. When using the QOLSR protocol, there are cases in which a source node continuously changes a flows next hop in response to the change of available bandwidth on its path and cannot tell apart the traffic induced by itself from traffic generated by other nodes. The article describes a way to achieve QoS routing without using explicit reservation mechanisms and gives new distributed solutions to the oscillation and collision of flows. We can guarantee that the flows take the appropriate paths and avoid interferences with other existing flows. The performance of our distributed algorithm is extensively investigated by analyses, examples and simulations in both static and dynamic networks. Our results show that the gain achieved by our proposal represents an important improvement in mobile wireless ad hoc networks.

An efficient QOLSR extension protocol for QoS in ad hoc networks

Quality of service (QoS) support in mobile ad hoc networks (MANETs) is a challenging task. We have developed the QOLSR protocol, a QoS routing over OLSR (optimized link state routing) protocol introducing more appropriate metrics than the hop distance, such as bandwidth and delay. The paper discusses a proposed extension to the QOLSR protocol to provide integrated services, i.e., to support real-time as well as the current non-real-time service of IP. This extension is necessary to meet the growing need for real-time service for a variety of new applications, including teleconferencing, remote seminars. telescience, and distributed simulation. We include the various QoS parameters in the IPv6 flow label. The performance of our extension is extensively investigated by simulation. Our results indicate that the gain attained by our proposal represents an important improvement in such mobile wireless networks.

Admission control in wireless ad hoc networks: a survey

Wireless mobile ad hoc networks (MANETs) have emerged as a key technology for next-generation wireless networking. Because of their advantages over other wireless networks, MANETs are undergoing rapid progress and inspiring numerous applications. However, many technical issues are still facing the deployment of this technology, and one of the most challenging aspects is the quality of service (QoS) provisioning for multimedia real-time applications. MANETs are expected to offer a diverse range of services to support real-time traffic and conventional data in an integrated fashion. Because of the diversified QoS requirements of these services, QoS models are needed for an efficient usage of network resources. One of the most crucial mechanisms for providing QoS support is admission control (AC). AC has the task of estimating the state of networks resources and thereby to decide which application data flows can be admitted without promising more resources than are available and thus violating previously made guarantees. In order to provide a better understanding of the AC research challenges in MANETs, this paper presents a detailed investigation of current state-of-the-art AC models in ad hoc networks. A brief outline of the admission function, feedback to route failures, as well as the advantages and drawbacks of each discussed model are given.

An efficient mobility management in wireless overlay networks

Mobile IP (and Ipv6) is used to keep track of location information and make the data available to the mobile device anytime, anywhere. It designed to address the macro mobility management, it does not address micro-level mobility issues such as handoff latency and packet loss. In this paper, we propose a mobility management scheme to handle the movements of mobile nodes among different wireless network technologies. Our scheme combines: (a) A hierarchical mobility management architecture to hide mobility of mobile nodes within the foreign domain from the home agent (b) The use of multicast as the packet forwarding mechanism from the gateway foreign agent to the base stations (c) A scheme for users with high-mobility/low-mobility to minimize packet loss (d) The use of forwarding pointers to help in providing efficient location management without informing the home agent. We also present simulation results showing that the loss rate can be minimized for faster moving mobiles. The case of a mobile changing speed is also addressed.

Fast and efficient vertical handoffs in wireless overlay networks

Mobile IP is used to keep track of location information and make the data available to the mobile device anytime, anywhere. It designed to address the macromobility management problem, it does not address microlevel mobility issues such as handoff latency and packet loss. In this paper, we propose a fast and efficient handoff scheme to handle the movements of mobile nodes among a different wireless network technologies. Our scheme combines: (a) A hierarchical mobility management architecture to hide mobility of mobile nodes within the foreign domain from the home agent, (b) The use of multicast as the packet forwarding mechanism from the getaway foreign agent to the base stations, (c) The use of our proposed virtual cells in order to reduce the upward vertical handoff latency and disruption as much as possible. Our design is based on the Internet protocol (IP) and is compatible with the mobile IP standard (MIP). We also present simulation results showing that our handoff scheme is very fast and avoid packet loss.

An efficient bandwidth guaranteed routing for ad hoc networks using ieee 802.11 with interference consideration

In multi-hop wireless networks, flows that traverse the same geographical vicinity contend for the same wireless channel capacity. This is in sharp contrast with wireline networks, where only flows that traverse the same link contend for its capacity. Providing bandwidth guaranteed service in ad hoc networks therefore requires consideration of the underlying interference model. To address this issue, we first separate the underlying scheduling problem from QoS routing with guaranteed bandwidth, by presenting clique (complete subgraph) based constraints as the feasibility conditions for flows. We use packet level simulations in OPNET to compare the throughput achieved by distributed MAC protocol like 802.11b with the capacity predicted by our theoretical constraints. Simulations demonstrate that clique constraints are sufficient if they are satisfied on a network whose link capacities are scaled by a factor β according to the variation in interference range used by our interference model. As an example, we integrate our link capacity estimation model to the QOLSR routing protocol functioning. Simulation results show that QOLSR protocol yields better performance compared to the best-effort OLSR protocol.