Simulation & Performance Evaluation of QoS Routing Protocol for Adhoc Networks Using Directional Communication

We have proposed a scheme for supporting priority-based QoS in mobile ad hoc networks by classifying the traffic flows in the network into different priority classes, and giving different treatment to the flow-rates belonging to different classes. We have adopted a control-theoretic approach to adaptively control the low-priority flows so as to maintain the high priority flow-rates at their desired level, thus guaranteeing QoS to high-priority flow. At the same time, our objective is to adaptively maximize low priority flows while maintaining high priority flows at a desired level so that full utilization of wireless medium can be achieved through adaptive rate control. To provide this desired service guarantee to high priority flows, we need a distributed flow-control algorithm. Here, the low priority flows, causing interference to a high priority flow, detect and measure high priority flow-rate at each node on their routes and consequently adjust their flow-rates using a feedback control mechanism to maintain the high priority flow at its desired level. This detection and measurement is done at MAC layer of each node participating in routing from source to destination. We have proposed this protocol with a very nominal overhead using omni-directional antenna and modified the scheme to show the overall improvement in throughput using directional antenna. The performance has been evaluated using QualNet network simulator and the results indicate the effectiveness of our scheme.

In this paper, we propose a new quality-of-service (QoS) routing protocol for mobile ad hoc network (MANET) using directional antennas. The proposed scheme offers a bandwidth-based routing protocol for QoS support in MANET using the concept of multi-path. Our MAC sub-layer adopts the CDMA-over-TDMA channel model. The on-demand QoS routing protocol calculates the end-to-end bandwidth and allocates bandwidth from the source node to the destination node. The paths are combined with multiple cross links, called shoelace, when the network bandwidth is strictly limited. Due to the property of the directional antenna, these cross links can transmit data simultaneously without any data interference. We develop a shoelace-based on-demand QoS routing protocol by identifying shoelaces in a MANET so as to construct a QoS route, which satisfied the bandwidth requirement, more easily. The shoelace-based route from the source to the destination is a route whose sub-path is constructed by shoelace structure. With the identified shoelaces, our shoelace-based scheme offers a higher success rate to construct a QoS route. Finally, simulation results demonstrate that the proposed routing protocol outperform existing QoS routing protocols in terms of success rate, throughput, and average latency.

Quality of service (QoS) in wireless 802.11 networks cannot be achieved without the support for service differentiation at the medium access layer. IEEE802.11 suffers from QoS limitations that have often been summarized in the literature. We present simulation results to show the effectiveness of several proposed techniques of improving the QoS in the IEEE802.11 protocol. Specifically, we closely examine the sliding contention window (SCW) technique and present a performance study that augments the work done by the original authors, by considering the determinism of QoS achieved. We find that simple approaches such as priority queuing and differential inter-frame spacing provide service differentiation at a single station but are not successful in providing it across a number of stations. Further, we find that the SCW approach provides a high service differentiation and deterministic QoS guarantees. It achieves these by a strict separation of the contention window range of different priority classes. Further, it measures and reacts to losses suffered by high priority flows at the MAC layer and to the increase in network load. These cross layer design techniques help SCW maintain good performance even at high network load. However, this strict service differentiation comes at the cost of reduced performance of low priority flows at heavy load.

Improving the performance of the Mobile Ad hoc NETworks (MANETs) is a challenge. MANETs present several constraints such as dynamic topology, wireless link communication and limited resources like bandwidth and energy. Routing without taking into account these constraints degrades performance and aggravates congestion problem. This paper proposes a new solution combining QoS (Quality of Service) routing protocol and flow control mechanism. This QoS routing protocol selects the routes with more resources in an intelligent manner rather than diffusion. It returns the best route offering a higher transmission rate, a less delay and a more stability. This protocol uses a new metric to compute the most stable route. To reinforce the congestion avoidance, we add a flow control mechanism to adjust the sender's transmission rate for each route. The solution is modeled by the ant systems. The results obtained under the Network Simulator (NS2.31) show that our QoS routing protocol improves the network performance compared to QoS-AODV protocol. The addition of flow control mechanism produces significant improvements in network system performance.

In Mobile Ad-Hoc Networks (MANET), the increasing demand for multimedia application is more challenging and the existing routing protocols are not adequate owing to the complex design requirements of Quality of Service (QoS) routing. This paper proposes a stateless position-based solution for QoS routing issues and offers an efficient end-to-end communication guarantee. The proposed Stateless QoS (SQoS) routing protocol is based on adaptive compass greedy routing to determine a qualified path which satisfies the QoS requirements and the void handling scheme overcomes the local maximum issue. In addition, the SQoS routing utilises the node overhearing capacity to obtain the link quality measurement to provide a guarantee for efficient end-to-end transmission through the identification of high-quality links for multimedia streams. The performance of the proposed SQoS routing protocol is compared with existing QoS-GPSR. Finally, the performance evaluation proves that the SQoS routing protocols outperform the existing protocols.

The quality-of-service (QoS) communication that supports mobile applications to guarantee bandwidth utilization is an important issue for Bluetooth wireless personal area networks (WPANs). In this paper, we address the problem of on-demand QoS routing with interpiconet scheduling in Bluetooth WPANs. A credit-based QoS (CQ) routing protocol is developed which considers different Bluetooth packet types because of different types of Bluetooth packets have different bandwidth utilization levels. This work improves the bandwidth utilization of Bluetooth scatternets by providing a new interpiconet scheduling scheme. Centralized and distributed algorithms are investigated in this work to improve the bandwidth utilization for the on-demand QoS routing protocol The performance analysis illustrates that our credit-based QoS routing protocol achieves enhanced performances, compared to existing QoS routing protocols.

Previous quality‐of‐service (QoS) routing protocols in mobile ad hoc networks (MANETs) determined bandwidth‐satisfied routes for QoS applications. Since the multi‐rate enhancements have been implemented in MANETs, QoS routing protocols should be adapted to exploit them fully. However, existing works suffer from one bandwidth‐violation problem, named the hidden route problem (HRP), which may arise when a new flow is permitted and only the bandwidth consumption of the hosts in the neighborhood of the route is computed. Without considering the bandwidth consumption to ongoing flows is the reason the problem is introduced. This work proposes a routing protocol that can avoid HRP for data rate selection and bandwidth‐satisfied route determination with an efficient cross‐layer design based on the integration of PHY and MAC layers into the network layer. To use bandwidth efficiently, we aim to select the combination of data rates and a route with minimal bandwidth consumption to the network, instead of the strategy adopted in the most previous works by selecting the combination with the shortest total transmission time. Using bandwidth efficiently can increase the number of flows supported by a network. Copyright 2010 John Wiley & Sons, Ltd.

Even without possible interference from external radio sources, the problem of guaranteeing quality-of-service (QoS) routing in mobile ad hoc networks (MANETs) is a difficult problem. Difficulties arise because node mobility can cause frequent network topology changes, communication channels can have high error rates, the jitter rate is high and several different applications can be sharing the use of the communication medium. This paper addresses these issues and proposes a new QoS routing protocol for MANETs that combines aspects of a MAC protocol and a path reservation protocol. The proposed QoS routing protocol can be implemented based on any routing method that supports multiple paths (e.g., DSDV, TORA, PDR). The QoS performance of the proposed protocol is verified with simulations conducted using NS-2.KeywordsMobile ad hoc network (MANET)quality-of-service (QoS)routingtime division multiple access (TDMA)

While more and more real-time applications are expected in wireless mesh networks (WMNs), Quality of Service (QoS) provision is of foremost importance in order to support such real-time applications. In this paper, we proposed QRBC (QoS Routing protocol with Bandwidth Consideration), a protocol using a bandwidth guaranteed routing metric towards enhancing QoS support for the real-time applications in WMNs. The routing metric accurately reflects the available bandwidth of a route with the consideration of the interference caused by the hidden terminals in WMNs. During the route discovery process of QRBC, the routing metric is updated and used with the cooperation of admission control decision to find a bandwidth guaranteed routing path. Simulation results demonstrate that QRBC can find a less interfering and bandwidth guaranteed routing path for real-time applications by avoiding “hot-spots” with severe interference, which enhances the performance of such applications significantly.

An adhoc network is a collection of mobile nodes connected by a wireless link, where each node acts as a router. In order to facilitate the communication within the network, a routing protocol is needed. Due to bandwidth constraint and dynamic topology of the mobile adhoc Networks supporting Quality of Service (QoS) is challenging task. The aim of this work is to present QoS enabled routing protocol in adhoc networks and compare it with normal routing protocol. The Optimized Link State Routing (OLSR) protocol is an optimization of the classical link state protocol, which is used for implement the QoS. Such protocol is adopted for the reason that it reduces the size of control messages and minimizes the overhead from the flooding of control traffic. The performance of both routing and QoS routing protocols are evaluated using Network simulator Ns-2.QoS enabled routing protocol shows a significant improvement in protocol performance metrics applied in our measurements, such as packet delivery ratio, packet loss and delay.

Quality-of-service (QoS) routing in dynamic, wireless multi-hop ad hoc networks is a critical research issue, and various QoS protocols are proposed. However, those QoS routing protocols rarely provide multiple routes. Once links break, it takes time and brings large control overhead to establish new routes. This paper proposes a new QoS routing protocol, containing efficient bandwidth estimations, admission control and node-disjoint multi-path establishment. While detecting link breaks, we use back-up routes to avoid making wasteful route discovery. If a single route with sufficient bandwidth cannot be discovered, we propose to combine multiple routes to support QoS transmission. Simulation results show that the proposed QoS routing protocol increases throughput while provides satisfactory QoS.

Now a day's use of wireless communication is very common and growing faster. There are different types of wireless networks which are designed as per the requirement of data rate and coverage. In this paper scope is limited to widely study and used network called Mobile Ad hoc Network (MANET). MANET is collection of wireless devices which communicate among each other without need of any physical infrastructure as well as centralize administrations. Each mobile node in MANET acts as peer node. The communication is MANET is based on routing methods and hence since from last 2 decade there are number of routing methods designed with objective of improving the Quality of Service (QoS) performance of MANET. As the mobile nodes in MANET are moving randomly with varying mobility speed, this can leads the challenging tasks to achieve the guaranteed QoS performance. Therefore it is required to have efficient routing protocol with load balancing and dynamic behaviour of mobile nodes handling in MANET. In this paper, our goal first is to present the study on different QoS aware routing methods and non-routing methods designed by various research groups for MANET. Second objective is to design novel QoS Aware routing protocol for improving the QoS performance in MANET. Additionally, we are presenting the current research gap based on analysis of all recent methods of QoS improvement. The outcome of this paper is the current research problems and efficient QAODV routing method.

With the Development of mobile ad hoc network (MANET), Quality of Service (QoS) routing and power-aware routing become more and more important. In the past, QoS guarantee and power control issues were treated separately. In this paper, we propose a novel on-demand QoS routing protocol, PMQR (power-aware multi-path QoS routing) in TDMA-based MANETs. Our protocol combines QoS routing and power-aware routing, which can provide QoS guarantee and achieve energy conservation by taking into account both the transmission power and the remaining energy at the intermediate nodes between a source and a destination. PMQR also can establish multiple paths, even for a single call, when the route search cannot find a path that meets the QoS requirements. Simulation results show that PMQR has good network performance and balances the energy consumption of mobile hosts.

In Mobile Ad-hoc Networks (MANETs), each node is free to move and connect with one another over a wireless connection, without the requirement for a centralized controller or base station. These features make MANET useful and functional in a variety of areas, including tactical situations, sensor networks, rescue operations, and students on campus. However, this type of network also has a range of issues such as security, Quality of Service, dynamic topology, scalability, the absence of central management, and energy consumption. Since MANET nodes have little battery life, the power usage is among the most important design considerations in wireless ad-hoc networks. Each node is responsible for forwarding the packets to its neighboring nodes. Since the MANET does not contain a hierarchy, some nodes may not participate in forwarding the packets and prefer to keep their remaining energy for themselves; these nodes are called selfish nodes. The presence of selfish nodes in the MANET greatly affects the efficiency and activity of the network. The process of detecting and isolating the selfish node does not constitute an easy task. It still requires further investigation and study. Therefore, this survey is intended to determine, study and analyze some new detection mechanisms used in detecting selfish nodes in MANETs. It also classifies them into three categories which are credit-based, reputation-based, and acknowledgment-based techniques. In addition, it highlights some critical issues in MANET according to selfish behavior, and points out the necessary requirements for better improvement as well as fields for future research.

Now a day, Mobile Adhoc Networks (MANET) gained a lot of popularity in the research community. People realized that there is a commercial value in MANETs with the successful solutions of the most basic but important problems in network layer. Mostly all the applications that attracted interest in traditional wired networks (e.g. Audio/Video Transfer, Video Conferencing, Watching Online Movies/Sports, Camera-enabled Messenger, Online Gaming etc.) would attract interest for MANETs as well. Since real-time multimedia communications will be common in MANETs, there has been an increasing motivation on the introduction of QoS in such networks. But, many characteristics of MANETs make QoS provisioning a difficult problem. In MANETs, providing QoS guarantees is very difficult and challenging than in traditional wired networks, mainly due to multihop communications, contention for channel access, node mobility and a lack of central coordination. However, in the last few years, much research attention has focused on providing QoS guarantees in MANET routing protocols. QoS routing protocol/mechanism is key issue in provision of QoS in MANETs. There are number of QoS routing approaches have been proposed in literature, focusing on different QoS metrics but no particular protocol/mechanism provides overall solution. There are some major open research issues in this area such as QoS metric selection and cost function design, Multi-class traffic, Scheduling mechanism at source, Packet prioritization for control messages, QoS routing that allows preemption, and QoS in Heterogeneous networks. There are still many open questions that must be solved to improve the performance of QoS-aware routing protocols such as bandwidth/delay estimation, route discovery, resource reservation, route maintenance, cross-layer design, energy consumption, multicast QoS routing etc.