Dynamic QoS Allocation for Multimedia Ad Hoc Wireless Networks

In this paper, we propose an approach to support QoS for multimedia applications in ad hoc wireless network. An ad hoc network is a collection of mobile stations forming a temporary network without the aid of any centralized coordinator and is different from cellular networks which require fixed base stations interconnected by a wired backbone. It is useful for some special situations, such as battlefield communications and disaster recovery. The approach we provide uses CSMA/CA medium access protocol and additional reservation and control mechanisms to guarantee quality of service in ad hoc network system. The reason we choose CSMA protocol instead of other MAC protocols is that it is used in most of currently wireless LAN productions. Via QoS routing information and reservation scheme, network resources are dynamically allocated to individual multimedia application connections.     

QM2RP: A QoS-Based Mobile Multicast Routing Protocol Using Multi-Objective Genetic Algorithm

With the increasing demand for real-time services in next generation wireless networks, quality-of-service (QoS) based routing offers significant challenges. Multimedia applications, such as video conferencing or real-time streaming of stock quotes, require strict QoS guarantee on bandwidth and delay parameters while communicating among multiple hosts. These applications give rise to the need for efficient multicast routing protocols, which will be able to determine multicast routes that satisfy different QoS constraints simultaneously. However, designing such protocols for optimizing multiple objectives, is computationally intractable. Precisely, discovering optimal multicast routes is an NP-hard problem when the network state information is inaccurate – a common scenario in wireless networks. Based on the multi-objective genetic algorithm (MOGA), in this paper we propose a QoS-based mobile multicast routing protocol (QM²RP) that determines near-optimal routes on demand. Our protocol attempts to optimize multiple QoS parameters, namely end-to-end delay, bandwidth requirements, and residual bandwidth utilization. Furthermore, it is fast and efficient in tackling dynamic multicast group membership information arising due to user mobility in wireless cellular networks. Simulation results demonstrate that the proposed protocol is capable of discovering a set of QoS-based, near-optimal multicast routes within a few iterations, even with imprecise network information. Among these routes one can choose the best possible one depending on the specified QoS requirements. The protocol is also scalable and yields lower multicast call-blocking rates for dynamic multicast group size in large networks.     

QoS routing in ad hoc wireless networks

The emergence of nomadic applications have generated much interest in wireless network infrastructures that support real-time communications. We propose a bandwidth routing protocol for quality-of-service (QoS) support in a multihop mobile network. The QoS routing feature is important for a mobile network to interconnect wired networks with QoS support (e.g., ATM, Internet, etc.). The QoS routing protocol can also work in a stand-alone multihop mobile network for real-time applications. This QoS routing protocol contains end-to-end bandwidth calculation and bandwidth allocation. Under such a routing protocol, the source (or the ATM gateway) is informed of the bandwidth and QoS available to any destination in the mobile network. This knowledge enables the establishment of QoS connections within the mobile network and the efficient support of real-time applications. In addition, it enables more efficient call admission control. In the case of ATM interconnection, the bandwidth information can be used to carry out intelligent handoff between ATM gateways and/or to extend the ATM virtual circuit (VC) service to the mobile network with possible renegotiation of QoS parameters at the gateway. We examine the system performance in various QoS traffic flows and mobility environments via simulation. Simulation results suggest distinct performance advantages of our protocol that calculates the bandwidth information. It is particularly useful in call admission control. Furthermore, “standby” routing enhances the performance in the mobile environment. Simulation experiments show this improvement     

A novel multicast traffic engineering technique in SDN using TLBO algorithm

In recent years, multicast communication is widely used by network providers to deliver multimedia contents. Quality of service (QoS) provisioning is one of the most important issues while transmitting multimedia contents using multicast. Traditional IP multicasting techniques suffer from reliability, scalability and have limitations to provide appropriate QoS for multimedia applications based on service level agreement (SLA). Nowadays, the advent of software defined networking (SDN), enables network providers to manage their networks dynamically and guarantee QoS parameters for customers based on SLA. SDN provides capabilities to monitor network resources and allows to dynamically configure desired multicasting policies. In this paper, we proposed a novel multicasting technique to guarantee QoS for multimedia applications over SDN. To deliver multimedia contents in an efficient manner, our proposed method models multicast routing as a delay constraint least cost (DCLC) problem. As DCLC problem is NP-Complete, we proposed an approximation algorithm using teaching–learning-based optimization to solve this problem. We evaluated our proposed method under different topologies. Experimental results confirmed that our proposed method outperforms IP multicast routing protocol, and it achieves a gain of about 25% for peak signal-to-noise ratio.     

A novel real-time scheme for (m,k)-firm streams in wireless sensor networks

The multimedia transmission based real-time applications have posed a big challenge to wireless sensor networks (WSNs) where both reliability and timeliness need to be guaranteed at the same time, to support an acceptable Quality of Service (QoS). The existing real-time routing protocols, however, are not able to meet the QoS requirements of realtime applications because of the inherent resource constraint of sensor nodes and instability of wireless communication. Therefore, we propose a real-time scheme in this paper, including a QoS-aware routing protocol and a set of fault recovery mechanisms, for (m,k)-firm based real-time applications over WSNs. A local status indicator which is specially devised for (m,k)-firm stream, is used for intermediate nodes to monitor and evaluate their local conditions. The proposed routing protocol takes into account of packet deadline, node condition and remaining energy of next hop, to make optimal forwarding decision. Additionally, according to the stream QoS and node condition, the proposed fault recovery mechanisms are utilized for nodes to handle the congestion, link failure and void problems occurred during transmission and remain the desired reliability and timeliness requirements. The proposed scheme has been well studied and verified through simulations. The results have proved the efficiency of the proposed scheme in terms of high successful transmission ratio, small end-to-end delay and long lifetime of network.     

GMCAR: Grid-based multipath with congestion avoidance routing protocol in wireless sensor networks

Recently, the interest in wireless sensor networks has been magnetized in the delay sensitive applications such as real-time applications. These time critical applications crave certain QoS requirements as though end-to-end delay guarantee and network bandwidth reservation. However, the severe resource constraints of the wireless sensor networks pose great challenges that hinder supporting these requirements. In this paper, we propose a Grid-based Multipath with Congestion Avoidance Routing protocol (GMCAR) as an efficient QoS routing protocol that is suited for grided sensor networks. We employ the idea of dividing the sensor network field into grids. Inside each grid, one of the sensor nodes is selected as a master node which is responsible for delivering the data generated by any node in that grid and for routing the data received from other master nodes in the neighbor grids. For each master node, multiple diagonal paths that connect the master node to the sink are stored as routing entries in the routing table of that node. The novelty of the proposed protocol lies behind the idea of incorporating the grids densities along with the hop count into the routing decisions. A congestion control mechanism is proposed in order to relieve the congested areas in case of congestion occurrence. Simulation results show that our proposed protocol has the potential to achieve up to 19.5% energy saving, 24.7% reduction in the delay and up to 8.5% enhancement in the network throughput when compared to another QoS routing protocol. However, when compared to the basic grid-based coordinated routing protocol, it achieves 23% energy saving. In addition, the proposed protocol shows its superiority in achieving better utilization to the available storage.     

Ad Hoc网络中QoS技术研究

服务质量保障是Ad Hoc网络环境中的一个复杂的急需解决的问题。首先论述了Ad Hoc网络的网络协议模型、QoS服务模型、QoS路由以及QoS保障策略等方面的问题,然后对其进行了综合分析,在此基础上,给出了Ad Hoc网络中不同层次的QoS路由方案以及其未来的研究方向。     

EARQ: Energy Aware Routing for Real-Time and Reliable Communication in Wireless Industrial Sensor Networks

Wireless industrial sensor networks are wireless sensor networks which have been adapted to industrial applications. Most techniques for wireless sensor networks can be applied to wireless industrial sensor networks. However, for industrial applications of wireless industrial sensor networks, new requirements such as real-time, reliable delivery need to be considered. In this paper, we propose EARQ, which is a novel routing protocol for wireless industrial sensor networks. It provides real-time, reliable delivery of a packet, while considering energy awareness. In EARQ, a node estimates the energy cost, delay and reliability of a path to the sink node, based only on information from neighboring nodes. Then, it calculates the probability of selecting a path, using the estimates. When packet forwarding is required, it randomly selects the next node. A path with lower energy cost is likely to be selected, because the probability is inversely proportional to the energy cost to the sink node. To achieve real-time delivery, only paths that may deliver a packet in time are selected. To achieve reliability, it may send a redundant packet via an alternate path, but only if it is a source of a packet. Experimental results show that EARQ is suitable for industrial applications, due to its capability for energy efficient, real-time, reliable communications.      

QUORUM—Quality of Service in Wireless Mesh Networks

Wireless mesh networks (WMNs) can provide seamless broadband connectivity to network users with low setup and maintenance costs. To support next-generation applications with real-time requirements, however, these networks must provide improved quality of service guarantees. Current mesh protocols use techniques that fail to accurately predict the performance of end-to-end paths, and do not optimize performance based on knowledge of mesh network structures. In this paper, we propose QUORUM, a routing protocol optimized for WMNs that provides accurate QoS properties by correctly predicting delay and loss characteristics of data traffic. QUORUM integrates a novel end-to-end packet delay estimation mechanism with stability-aware routing policies, allowing it to more accurately follow QoS requirements while minimizing misbehavior of selfish nodes.     

Route Stability Based QoS Routing in Mobile Ad Hoc Networks

To provide high quality communications service among mobile wireless devices is basically a challenging task in wireless ad hoc networks. In this paper, we propose a Route Stability based QoS Routing (RSQR) protocol in Mobile Ad Hoc Networks (MANETs) which is an extension of QoS routing with throughput and delay constraints. Ensuring a data path to be valid for sufficiently longer period of time is a very difficult problem in MANET due to its highly dynamic nature. We propose a simple model for computing link stability and route stability based on received signal strengths. By including some extra fields in route request/reply packets, the route stability information can be utilized to select a route with higher stability among all the feasible routes between a given source destination pair. Further, inclusion of a signal strength based admission control enhances the performance of the routing. Results of our experiments show performance improvements in terms of packet delivery ratio, control overhead and average end-to-end delay in comparison with a QoS routing protocol proposed by Q. Xue and A. Ganz.     

SOAR: Simple Opportunistic Adaptive Routing Protocol for Wireless Mesh Networks

Multihop wireless mesh networks are becoming a new attractive communication paradigm owing to their low cost and ease of deployment. Routing protocols are critical to the performance and reliability of wireless mesh networks. Traditional routing protocols send traffic along predetermined paths and face difficulties in coping with unreliable and unpredictable wireless medium. In this paper, we propose a Simple Opportunistic Adaptive Routing protocol (SOAR) to explicitly support multiple simultaneous flows in wireless mesh networks. SOAR incorporates the following four major components to achieve high throughput and fairness: 1) adaptive forwarding path selection to leverage path diversity while minimizing duplicate transmissions, 2) priority timer-based forwarding to let only the best forwarding node forward the packet, 3) local loss recovery to efficiently detect and retransmit lost packets, and 4) adaptive rate control to determine an appropriate sending rate according to the current network conditions. We implement SOAR in both NS-2 simulation and an 18-node wireless mesh testbed. Our extensive evaluation shows that SOAR significantly outperforms traditional routing and a seminal opportunistic routing protocol, ExOR, under a wide range of scenarios.     

Provisioning of Parameterized Quality of Service in 802.11e Based Wireless Mesh Networks

There has been a growing interest in the use of wireless mesh networks. Today’s wireless technology enables very high data rate up to hundreds of Megabits per second, which creates the high demand of supporting real-time multimedia applications over wireless mesh networks. Hence it is imperative to support quality of service (QoS) in wireless mesh networks. In this paper, we design a framework to provide parameterized QoS in 802.11e based wireless mesh networks. Our framework consists of admission control algorithms and scheduling algorithms, which aim at supporting constant bit-rate (CBR) traffic flows, as well as variable bit-rate (VBR) traffic flows. We first present deterministic end-to-end delay bounds for CBR traffic. We then prove that the delay of VBR traffic can be bounded if the traffic flow conforms to a leaky-bucket regulator. We further study different admission control algorithms for VBR traffic. Our simulation results show that, by taking advantage of statistical multiplexing, much more traffic flows can be admitted.     

A Delay-Aware Wireless Sensor Network Routing Protocol for Industrial Applications

With the rapid development of information communication technologies, industrial manufacturing environments and requirements have changed considerably. Since wireless sensor networks have become more and more popular, our production chains have improved with respect to efficiency, flexibility and security. On the other hand, building a secure, robust and fast network is an essential issue for enterprises. In the past, few experts focused on this issue of industrial applications and most of solutions proposed are not suitable for industrial environments. In this paper, we propose a real-time routing protocol for mobile wireless sensor nodes in industrial environments, which offers superior quality of service in terms of delay time. We use geographic routing and information contained in the nodes routing table to extract location information. Then we calculate the node which is nearest to the target node to reduce hop counts and achieve fast data package transfers. It optimizes the packets forwarding hops, which in turn reduces the delay time effectively. We used OPNET to analyze our protocol and results indicate that this algorithm is useful and suitable for wireless sensor networks     

无线数字家庭网络泛在接入技术

数字家庭网络是通信领域的一个重要分支，近年来发展非常迅速。基于电信网络的数字家庭网络体系结构在中国已经标准化，但就接入方式而言，只是定义了可以使用无线方式，如何组建无线数字家庭网络是未来研究的重点。文章提出了无线数字家庭网络泛在接入概念，给出了无线泛在接入网络体系结构，并就其中的关键技术进行了探讨，包括感知无线电、无线网状网（Mesh）网络理论、通用接入点链路转换机制、业务的QoS保障机制以及电磁兼容和异构系统共存机制等。     

DREAM : Density Aware Overlay Multicast Forwarding in Mobile Ad Hoc Networks

Instead of multicast functionality on a network entity, the overlay multicast schemes support multicast service with help of underlying unicast routing protocol. However, due to a node's free migration and communication based on broadcasting capability, effectiveness of overlay multicast scheme is not guaranteed in Mobile Ad Hoc Networks (MANET). Specially, nodes' density within some areas changes frequently so heterogeneous forwarding scheme based on density is strongly desired in order to reduce a number of collisions as well as enhance resource utilization. To achieve this, in this paper, we introduce a new forwarding scheme, called as DREAM (Density aware overlay Multicast forwarding). A key feature of DREAM is to introduce a scoped flooding where the nodes densely locates, on the other hand, data forwarding based on unicast routing protocol is maintained in sparse environment. Distinct advantages are evaluated by simulation. Ki-Il Kim received the M.S. and Ph.D. degrees in computer science from the Chungnam National University, Daejeon, Korea, in 2002 and 2005, respectively. He is currently with Department of Information Science, Gyeongsang National University as a faculty member. His research interests include routing for MANET, QoS in wireless network, multicast, and sensor networks. Sang-Ha Kim received the B.S. degree in chemistry from Seoul National University, Seoul, Korea, in 1980. He received the M.S. and Ph.D. degrees in quantum scattering and computer science from the University of Houston, Houston, TX, in 1984 and 1989, respectively. From 1990 to 1991, he was with the Supercomputing Center, SERI, Korean Institute of Science and Technology (KIST) as Senior Researcher. He joined Chungnam National University, Daejeon,Korea, in 1992, where he is a Professor. His current research interests include wireless networks, ad hoc networks, QoS, optical networks, and network analysis.     

Cross-Layer Design for QoS Support in Multihop Wireless Networks

Due to such features as low cost, ease of deployment, increased coverage, and enhanced capacity, multihop wireless networks such as ad hoc networks, mesh networks, and sensor networks that form the network in a self-organized manner without relying on fixed infrastructure is touted as the new frontier of wireless networking. Providing efficient quality of service (QoS) support is essential for such networks, as they need to deliver real-time services like video, audio, and voice over IP besides the traditional data service. Various solutions have been proposed to provide soft QoS over multihop wireless networks from different layers in the network protocol stack. However, the layered concept was primarily created for wired networks, and multihop wireless networks oppose strict layered design because of their dynamic nature, infrastructureless architecture, and time-varying unstable links and topology. The concept of cross-layer design is based on architecture where different layers can exchange information in order to improve the overall network performance. Promising results achieved by cross-layer optimizations initiated significant research activity in this area. This paper aims to review the present study on the cross-layer paradigm for QoS support in multihop wireless networks. Several examples of evolutionary and revolutionary cross-layer approaches are presented in detail. Realizing the new trends for wireless networking, such as cooperative communication and networking, opportunistic transmission, real system performance evaluation, etc., several open issues related to cross-layer design for QoS support over multihop wireless networks are also discussed in the paper.     

CAC-OLSR: Extending OLSR to Provide Admission Control in Wireless Mesh Networks

This work presents an admission control mechanism for multi-hop wireless mesh networks based on the IEEE 802.11 standard and the OLSR routing protocol. This mechanism, called CAC-OLSR, aims at ensuring that traffic flows with quality of service (QoS) requirements, especially voice and video, are only admitted in the mesh network if it has available resources in order to provide flow requirements. In addition, QoS requirements of previously admitted traffic flows cannot be violated. The proposal was evaluated with NS-2 and Evalvid simulations.     

QoS Routing for Mesh-Based Wireless LANs

Wireless LANs with their increased data rate become an attractive technology for connecting mobile users to the Internet. Efficient deployment of wireless LANs will require the ability to extend the wireless LANs coverage without the need to deploy a very large number of access points. Mesh-based wireless LANs are an attractive solution to this problem. These networks extend wireless LAN coverage by using each node in the network as a router, resulting in a multihop topology. In this paper we introduce a novel routing algorithm, wireless mesh routing (WMR), that provides quality-of-service (QoS) support and accounts for the characteristics of both infrastructure-based wireless LANs and ad hoc networks. The algorithm is validated using the OPNET modeler. The simulation results show that the mesh network using WMR protocol can provide QoS support and react dynamically to the network status changes with low control overheads. Using the proposed software architecture the proposed routing protocol can be implemented with any MAC protocol, resulting in easy implementation in existing wireless nodes.