Novel power-based routing metrics for multi-channel multi-interface wireless mesh networks

In this paper the problem of selecting optimal paths in a MCMI (Multi-Channel Multi-Interface) WMN (Wireless Mesh Network) is considered. The WMNs are characterized by high dynamic range of the received signal level, especially in the indoor environment. To improve the existing routing metrics and track fast changes that occur in the link state, a corresponding parameter based on the received signal level was assigned to each link. By combining this parameter and known metrics, ETX (Expected Transmission Count), WCETT (Weighted Cumulative ETT) and MIC (Metric of Interference and Channel-switching), three new metrics were formed. All metrics were incorporated in MCR (Multi Channel Routing) protocol and an appropriate propagation model was used for simulations in a real, indoor environment. Proposed metrics, original metrics, MCR protocol, and indoor propagation model were implemented in Glomosim simulator. New metrics were compared against known metrics and also among each other in terms of throughput of user data and average end-to-end delay of the network. The results have shown that proposed metrics significantly outperform original metrics. With this approach, better network performance can be achieved without any additional hardware and with minimal software changes.     

QoS-aware cooperative medium access control for MIMO ad-hoc networks

To exploit multiuser diversity and achieve QoS requirements in MIMO ad hoc networks, we propose an optimal scheduling policy which utilizes stream control schemes. We also present a medium access control (MAC) protocol to implement the optimal scheduling policy. Simulation results show that our implementation achieves higher network throughput and provides better QoS support than the existing solutions.     

Design and implementation of multicasting for multi-channel multi-interface wireless mesh networks

Multicasting is a useful communication method in wireless mesh networks (WMNs). Many applications in WMNs require efficient and reliable multicast communications, i.e., high delivery ratio with low overhead among a group of recipients. In spite of its significance, little work has been done on providing such multicast service in multi-channel WMNs. Traditional multicast protocols for wireless and multi-hop networks tend to assume that all nodes, each of which is equipped with a single interface, collaborate on the same channel. This single-channel assumption is not always true, as WMNs often provide nodes with multiple interfaces to enhance performance. In multi-channel and multi-interface (MCMI) WMNs, the same multicast data must be sent multiple times by a sender node if its neighboring nodes operate on different channels. In this paper, we try to tackle the challenging issue of how to design a multicast protocol more suitable for MCMI WMNs. Our multicast protocol builds multicast paths while inviting multicast members, and tries to allocate the same channel to neighboring members in a bottom-up manner. By unifying fixed channels of one-hop multicast neighbors, the proposed algorithm can improve the performance such as reducing multicast data transmission overhead and delay, while managing a successful delivery ratio. In order to prove such expectation on the performance, we have implemented and evaluated the proposed solution on the real testbed having the maximum 24 nodes, each of which is equipped with two IEEE 802.11a Atheros WLAN cards.     

An adaptive load-aware routing algorithm for multi-interface wireless mesh networks

In wireless mesh networks, the number of gateway nodes are limited, when the nodes access to the internet by fixed gateway node, different requirements of nodes lead to the dataflow shows heterogeneity. Many new routing metrics and algorithms existing in traditional wired networks and the Ad Hoc network, can not be directly applied to wireless mesh networks, so how to design a routing metric and algorithm which can dynamically adapt to current networks topology and dataflow changes, avoid bottleneck node, and select the most stable and least congestion link to establish a route is very important. In this paper, we presented a new dynamic adaptive channel load-aware metric (LAM) to solve the link load imbalance caused by inter-flow and inner-flow interference, designed a self-adaptive dynamic load balancing on-demand routing algorithm through extending and improving AODV routing method with the LAM, to achieve flow balance, reduce the high packet loss ratio and latency because congestion and Packet retransmission, and can increase Network Throughput.     

A tabu search algorithm for routing optimization in mobile ad-hoc networks

In this paper, we propose a routing optimization algorithm to efficiently determine an optimal path from a source to a destination in mobile ad-hoc networks. To determine an optimal path for the nodes is important for transmitting data between nodes in densely deployed networks. In order to efficiently transmit data to its destination, the appropriate routing algorithms must be implemented in mobile ad-hoc networks. The proposed algorithm is designed by using a tabu search mechanism that is a representative meta-heuristic algorithm. The proposed tabu search algorithm carries out two neighborhood generating operations in order to determine an optimal path and minimize algorithm execution time. We compare the proposed tabu search algorithm with other meta-heuristic algorithms, which are the genetic algorithm and the simulated annealing, in terms of the routing cost and algorithm execution time. The comparison results show that the proposed tabu search algorithm outperforms the other algorithms and that it is suitable for adapting the routing optimization problem.     

QRON: QoS-aware routing in overlay networks

Recently, many overlay applications have emerged in the Internet. Currently, each of these applications requires their proprietary functionality support. A general unified framework may be a desirable alternative to application-specific overlays. We introduce the concept of overlay brokers (OBs). We assume that each autonomous system in the Internet has one or more OBs. These OBs cooperate with each other to form an overlay service network (OSN) and provide overlay service support for overlay applications, such as resource allocation and negotiation, overlay routing, topology discovery, and other functionalities. The scope of our effort is the support of quality-of-service (QoS) in overlay networks. Our primary focus is on the design of QoS-aware routing protocols for overlay networks (QRONs). The goal of QRON is to find a QoS-satisfied overlay path, while trying to balance the overlay traffic among the OBs and the overlay links in the OSN. A subset of OBs, connected by the overlay paths, can form an application specific overlay network for an overlay application. The proposed QRON algorithm adopts a hierarchical methodology that enhances its scalability. We analyze two different types of path selection algorithms. We have simulated the protocols based on the transit-stub topologies produced by GT-ITM. Simulation results show that the proposed algorithms perform well in providing a QoS-aware overlay routing service.     

Agent-based trusted on-demand routing protocol for mobile ad-hoc networks

The routing performance in mobile ad hoc networks (MANETs) relies on the co-operation of the individual nodes that constitute the network. The existence of misbehaving nodes may paralyze the routing operation in MANETs. To overcome this behavior, the trustworthiness of the network nodes should be considered in the route selection process combined with the hop count. The trustworthiness is achieved by measuring the trust value for each node in the network. In this paper, a new protocol based on self monitoring (agent-based) and following the dynamic source routing (DSR) algorithm is presented. This protocol is called agent-based trusted dynamic source routing protocol for MANETs. The objective of this protocol is to manage trust information locally with minimal overhead in terms of extra messages and time delay. This objective is achieved through installing in each participated node in the network a multi-agent system (MAS). MAS consists of two types of agents: monitoring agent and routing agent. A new mathematical and more realistic objective model for measuring the trust value is introduced. This model is weighted by both number and size of routed packets to reflect the “selective forwarding” behavior of a node. The performance evaluation via simulation shows that our protocol is better than standard and trusted DSR. The simulation is done over a variety of environmental conditions such as number of malicious nodes, host density and movement rates.     

J-CAR: An efficient joint channel assignment and routing protocol for IEEE 802.11-based multi-channel multi-interface mobile Ad Hoc networks

The capacity of an IEEE 802.11-based multi-hop wireless network is limited. By effectively utilizing multiple non-overlapping channels and multiple interfaces, collision and co-channel interference can be reduced. This allows more concurrent transmissions and thus enhances the network capacity. In this paper, we introduce an efficient distributed joint channel assignment and routing protocol, called J-CAR¹. Unlike existing schemes, J-CAR allows a data interface to dynamically change its working mode between send and receive on a call-by-call basis, which enhances the utilization of both interface and channel. In J-CAR, channels are negotiated and assigned to active links in conjunction with the on-demand routing process. At each hop, J-CAR conducts a local optimization by selecting the least interfered channel according to the channel interference index. The channel interference index is designed by taking both the protocol and physical interference models into consideration. To find the least interfered path for network load balancing on a global scale, J-CAR employs a length-constrained widest-path routing. The “width” of a path is determined by the interference level of its bottleneck link. With an adjustable threshold on the path length (with respect to the shortest-path), the excessively long path can also be avoided. We show that with a comparable complexity as the existing schemes, J-CAR provides much higher system goodputs and shorter end-to-end packet delays.     

A virtual multiple message ferry backbone routing scheme for mobile ad-hoc networks

A MANET (Mobile Ad-Hoc Network) consists of relocating wireless communication devices without infrastructure installed in its network environment. Due to the mobility of the devices, the network topology changes frequently and consequently results in poor network performance. When the density of nodes in a MANET is sparse, the performance becomes even worse due to the intermittent connected routing problem arising. To cope with this problem, this paper integrates mechanisms of Virtual Multiple Message Ferry Routing (VMMFR) and Virtual Multiple Message Ferry Dispatch Scheduling (VMMFDS) into the routing protocol design of MANETs and proposes a Virtual Multiple Message Ferry Backbone Routing (VMMFBR) scheme for MANETs. Several simulations have been conducted using the network simulator NS-2 to evaluate the performance of the proposed VMMFR mechanism. Due to the VMMFR mechanism providing a reliable and predictable backbone routing for MANETs communications. The results show that the proposed method has a higher packet delivery ratio, low bandwidth consumed, and that there is greater precision of packet delivery time, compared to the traditional MANETs routing protocols (AOMDV and DSR). In addition, some theoretical results for the proposed VMMFDS mechanism to minimize the transfer waiting time are also given in this paper.     

A QoS-aware congestion control mechanism for wireless multimedia sensor networks

Wireless Networks - The amount of data produced by multimedia sensor nodes (such as video/audio sensors), is considerably huge comparing with the data of scalar sensor nodes. The great numbers of...     

QoS-aware routing based on bandwidth estimation for mobile ad hoc networks

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support.     

A QoS-aware multicast routing protocol

The future Internet is expected to support multicast applications with quality of service (QoS) requirements. To facilitate this, QoS multicast routing protocols are pivotal in enabling new receivers to join a multicast group. However, current routing protocols are either too restrictive in their search for a feasible path between a new receiver and the multicast tree, or burden the network with excessive overhead. We propose QMRP, a new QoS-aware multicast routing protocol. QMRP achieves scalability by significantly reducing the communication overhead of constructing a multicast tree, yet it retains a high chance of success. This is achieved by switching between single-path routing and multiple-path routing according to the current network conditions. The high level design of QMRP makes it operable on top of any unicast routing algorithm in both intradomain and interdomain. Its responsiveness is improved by using a termination mechanism which detects the failure as well as the success of routing without the use of timeout. In addition, QMRP always constructs loop-free multicast trees     

Integrating service discovery with routing and session management for ad-hoc networks

In this paper, we propose GSR: a new routing and session management protocol for ad-hoc networks as an integral part of a service discovery infrastructure. Traditional approaches place routing at a layer below service discovery. While this distinction is appropriate for wired networked services, we argue that in ad-hoc networks this layering is not as meaningful and show that integrating routing with discovery infrastructure increases system efficiency. Central to our protocol is the idea of reusing the path created by the combination of a service discovery request and a service advertisement for data transmission. This precludes the need to use separate routing and discovery protocols. GSR also combines transport layer features and provides end-to-end session management that detects disconnections, link and node failures and enables service-centric session redirection to handle failures. This enables GSR to accommodate service-centric routing apart from the traditional node-centric routing. We compare GSR with AODV in terms of packet delivery ratio, response time and average number of hops traveled by service requests as well as data. GSR achieves better packet delivery ratio with a minor increase of the average packet delivery delay.     

A secure and trust based on-demand multipath routing scheme for self-organized mobile ad-hoc networks

A mobile ad hoc network (MANET) is a self-configurable network connected by wireless links. This type of network is only suitable for provisional communication links as it is infrastructure-less and there is no centralized control. Providing QoS and security aware routing is a challenging task in this type of network due to dynamic topology and limited resources. The main purpose of secure and trust based on-demand multipath routing is to find trust based secure route from source to destination which will satisfy two or more end to end QoS constraints. In this paper, the standard ad hoc on-demand multi-path distance vector protocol is extended as the base routing protocol to evaluate this model. The proposed mesh based multipath routing scheme to discover all possible secure paths using secure adjacent position trust verification protocol and better link optimal path find by the Dolphin Echolocation Algorithm for efficient communication in MANET. The performance analysis and numerical results show that our proposed routing protocol produces better packet delivery ratio, reduced packet delay, reduced overheads and provide security against vulnerabilities and attacks.     

Locally-constructed trees for ad-hoc routing

We present a family of self-stabilizing distributed algorithms to built a spanning tree on the underlying communications graph of an ad-hoc wireless network. Next, based on this principle, we show how to construct overlaying structures which are suitable for routing tasks.     

QoS-aware energy-saving mechanism for hybrid optical-wireless broadband access networks

Hybrid optical-wireless broadband access network (HOWBAN) takes full advantage of the high capacity and reliability of the passive optical network and the flexibility, ubiquity of the wireless network. Similar to other access networks, the issue of high energy consumption is a great challenge for HOWBAN. In HOWBAN, optical network units (ONUs) consume a great amount of energy. The sleep of ONUs can greatly improve the energy efficiency of HOWBAN. However, the quality of service (QoS) will be decreased while the packets are waiting in ONUs and optical line terminal. In this paper, we propose a QoS-aware energy-saving mechanism. A dynamic bandwidth allocation mechanism is designed to guarantee the QoS, where different priorities are considered. Meanwhile, we employ different sleep strategies by taking different priorities’ tolerant delays into account to prolong the sleep time of ONUs. Then, based on the evaluation of packet delay, the optimal sleep parameter is derived to maximum the energy efficiency. In addition, a load balancing and resource allocation mechanism is adopted in the wireless domain to reduce the delay and congestion caused by ONUs’ sleep. Results show that the proposed mechanism can effectively improve the energy efficiency and meet the QoS requirements of packets.     

A token-based routing mechanism for GMPLS-controlled WDM networks

This paper analyzes destination initiated reservation for Generalized Multi-Protocol Label Switching (GMPLS) based wavelength division multiplexing (WDM) networks and determines, via simulation, probabilities of both forward blocking and backward blocking. During light traffic load, any degradation in performance is due to backward blocking, whereas during heavy traffic load forward blocking dominates. In order to minimize performance degradation due to blocking, this paper proposes a token based routing scheme that is capable of searching for the availability of more than one route from source to destination, meeting the desired quality of service (QoS). Extensive simulation results show that the proposed technique significantly improves the blocking performance and setup delay.     

最稳路径的区播路由协议

Ad Hoc网络中,区播协议旨在把数据包传递到某一特定区域内的一组节点。本文首先讨论了现有区播协议存在的一些缺点,然后提出了一种改进的基于最稳路径的区播路由协议,该协议在源节点有大量数据需要发送时特别有效。     

High-throughput multi-channel MAC protocol with multi-interface cooperation

Low uti1ization of the interface a1ways exists in mu1ti-interface mu1ti-channe1（MIMC）medium access protoco1.Therefore,the mu1ti-interface cooperating（MIC）mechanism was proposed.A virtua1 MAC 1ayer was designed in mu1ti-interface node and mu1ti-interface cooperative mechanism through one successfu1 handshake of sing1e interface to estab1ish the synchronous transmission re1ationship between source-destination nodes a11 interface and data channe1 groups,thus improving the throughput and efficiency of contro1 frame.Furthermore,nodes with successfu1 transmission choose the current channe1 set as decision-making channe1s of the next transmission,which can effective1y reduce the impact of hidden termina1.The simu1ation resu1ts of MIC-MAC protoco1 show that the throughput has increased by 100% to 200% compared with MIMC-SMAC protoco1 and IEEE 802.11 in sing1e hop network,the co11ision and hidden termina1 prob1em have a1so been great1y optimized in mu1ti hop network.     

QoE-based routing algorithms for H.264/SVC video over ad-hoc networks

Multi-hop relaying combined with scarcity of wireless resources in ad-hoc networks can deteriorate the quality of service. As a result, one of the major challenges in video streaming over ad-hoc networks is enhancing users’ experience and network utilization. The emergence of scalable video coding standard enables smooth adaptation of video quality to network conditions. In this paper, we study two optimization problems: (1) maximize the global quality of experience of all users and (2) maximize the number of qualified streams. We formulate the both problems as mixed integer linear programming problems. These optimization problems are shown to be NP-hard. Consequently, we propose heuristic algorithms to solve them. Simulation results show that the proposed algorithms can provide the near-optimal video quality while the calculation times are much shorter than the one of optimal solution.