Learning automata based multi-flow opportunistic routing algorithm in wireless mesh networks

Opportunistic routing (OR) involves multiple forwarding candidates to relay packets by taking advantage of the broadcast nature and multi-user diversity of the wireless medium. Compared with Traditional Routing (TR), OR can evidently improve the end to end throughput of Wireless Mesh Networks (WMNs). At present, there are many achievements concerning OR in the single radio wireless network. However, the study of OR in multi-radio wireless network stays the beginning stage. In this paper, we focus on OR in multi-radio multi-channel WMNs. Directly using the existing channel assignment leads to decreasing the number of candidate forwarder and the performance of OR. According to OR with one-to-more transmission mode, the Candidate Forwarder Set based Channel Assignment (CFSCA) for OR is proposed. Firstly, according to the candidate forwarder selected by routing, we bound the sender node and its candidate forwarders as a Candidate Forwarder Set(CFS). Then we calculate the interference among all the CFSs. Then the channel assignment for OR is described as a minimum CFS interference optimization problem, which must obey the constraints of the channel number of CFS and the number of radio interfaces. The evaluation results show that CFSCA improves 25.2%, 10%, 19% of the aggregative throughput than random, uniform and tradition channel assignment, respectively.Keywordswireless mesh networksmulti-radio and multi-channelopportunistic routingchannel assignment

Routing in wireless mesh networks presents a great challenge due to unreliable wireless links and collisions. Recently, a new routing method, opportunistic routing (OR), is proposed to deal with them by exploiting broadcast nature of wireless networks. OR relies on the global knowledge of networks to select relays and determine priorities. In this paper, we propose a new routing scheme, OxDSR, which combines OR and dynamic source routing (DSR) and performs opportunistic transmissions with the help of the local information and the traditional route obtained by DSR. By taking the duplicates and additional wireless resource consumed by multiple ACK frames into consideration, we propose a new metric, equivalent data rate, to select and prioritize relays. Extensive simulation study shows that the proposed OxDSR is more resilient and achieves higher throughput than DSR based on the expected transmission count routing metric.

Wireless technology is emerging as a key technology for the future networks. Wireless mesh networks (WMNs) have emerged as an indispensable technology for deployment of wireless services for various applications in personal, enterprise, and metropolitan areas. Researchers are working actively in different fields of WMNs for providing better services. Routing protocols play a vital role in WMNs to provide reliable configuration and maintenance of topology of the network. Designing a suitable cost metric for routing protocols to provide quality links for data transmission is the backbone of WMNs. Many cost metrics have been proposed for WMNs and is still an active research topic as new performance metrics need to be discovered due to the dynamics of this field. This paper considers the genetic algorithm-based routing technique for WMN.We have studied the existing cost metrics and proposed a genetic algorithm technique for routing in WMN. To evaluate the genetic algorithm, and to determine the relative performance of the genetic algorithm in the context of routing in WMN, we carry out experiments on two test systems. We have evaluated the quality of the results produced by our algorithm with the traditional hop count metric results. Our results show that routing in WMN using genetic algorithm produces better results as compared to traditional hop count metric results. Finally, we carry out a detailed analysis of results, which help us in gaining an insight into the suitability of genetic algorithm for routing in WMN.

The emergence of nomadic multimedia applications, such as multimedia conferencing, distance learning, video phones, video/movie-on-demand, and education-on-demand, has recently generated much interest in multi-hop wireless mesh networks (WMNs) to support diverse Quality-of-Service (QoS). In the existing WMN QoS routing protocols, the methods of bandwidth calculation and allocation were proposed to determine routes with bandwidth guaranteed for QoS applications. This paper studies two NP-hard problems, the maximum bandwidth routing problem (abbreviated to MBRP) and the maximum flow routing problem (abbreviated to MFRP). Given a source node s and a destination node d in a multi-hop wireless mesh network, the MBRP is to determine an s-to-d path that can carry a maximum amount of traffic from s to d and the MFRP is to determine the maximum flow from s to d, both retaining the network bandwidth-satisfied. In this paper, heuristic algorithms for the two problems are proposed. Upper bounds on their optimal values are derived, and a lower bound is derived on the feasible value obtained for the MBRP. With the upper bound and the lower bound, an approximation ratio for the heuristic algorithm of the MBRP is obtained. The effectiveness of the heuristic algorithms is further verified by experiments. A generalized interference model is also discussed.

Finding the shortest route in wireless mesh networks is an important aspect. Many techniques are used to solve this problem like dynamic programming, evolutionary algorithms, weighted-sum techniques, and others. In this paper, we use dynamic programming techniques to find the shortest path in wireless mesh networks due to their generality, reduction of complexity and facilitation of numerical computation, simplicity in incorporating constraints, and their onformity to the stochastic nature of some problems. The routing problem is a multi-objective optimization problem with some constraints such as path capacity and end-to-end delay. Single-constraint routing problems and solutions using Dijkstra, Bellman-Ford, and Floyd-Warshall algorithms are proposed in this work with a discussion on the difference between them. These algorithms find the shortest route through finding the optimal rate between two nodes in the wireless networks but with bounded end-to-end delay. The Dijkstra-based algorithm is especially favorable in terms of processing time. We also present a comparison between our proposed single-constraint Dijkstra-based routing algorithm and the mesh routing algorithm (MRA) existing in the literature to clarify the merits of the former.

The wireless mesh networks (WMNs) have become one of the popular technologies of the wireless network utilization. WMN provides reliable and scalable wireless network because of its features such as dynamic self-organizing, self-configuring, Self-managing and self-healing. Routing protocols play an essential role in finding and establishing an active route from a source to a destination in WMNs. This article focuses on the performance evaluation and comparison of some routing protocols commonly used in WMNs for VoIP application: AODV, DSR, OLSR and TORA has been investigated over client Wireless Mesh Networks based on OPNET simulation in a different network sizes and mobility. This article presents a background of some designs and solutions based on an elaborated simulation investigation. The performance comparisons are carried out with regard to the node variation in network sizing and mobility. Based on the empirical outputs, the authors suggested that to utilize a specific routing protocol in certain situations.

Wireless Mesh Networks (WMNs) integrate the advantages of WLANs and mobile Ad Hoc networks, which have become the key techniques of next-generation wireless networks in the context of emergency recovery. Wireless Mesh Networks (WMNs) are multi-hop wireless networks with instant deployment, self-healing, self-organization and self-configuration features. These capabilities make WMNs a promising technology for incident and emergency communication. An incident area network (IAN) needs a reliable and lively routing path during disaster recovery and emergency response operations when infrastructure-based communications and power resources have been destroyed and no routes are available. Power aware routing plays a significant role in WMNs, in order to provide continuous efficient emergency services. The existing power aware routing algorithms used in wireless networks cannot fully fit the characteristics of WMNs, to be used for emergency recovery. This paper proposes a power aware routing algorithm (PARA) for WMNs, which selects optimal paths to send packets, mainly based on the power level of next node along the path. This algorithm was implemented and tested in a proven simulator. The analytic results show that the proposed power node-type aware routing algorithm metric can clearly improve the network performance by reducing the network overheads and maintaining a high delivery ratio with low latency.

Recently, opportunistic routing has gained much popularity for the ability to exploit the broadcast nature of the wireless medium with several practical protocols been proposed over wireless mesh networks (WMNs). These protocols usually add many mechanisms to introduce a dramatic increase in the overall network throughput, such as reliability promise and rate control. However, the evaluation of these protocols did not show how much performance benefit can be expected from each mechanism. In this paper, we provide a systematic performance evaluation on the effectiveness of reliability promise and rate control mechanisms that commonly used in opportunistic routing protocols. Our study shows that: (i) batch acknowledgment used in opportunistic routing significant improves the transmission performance over traditional routing, the true gain from opportunistic routing is not as much as claimed in previous works. (ii) rate control is important to the opportunistic routing. It ensures opportunistic routing to utilize its advantage sufficiently, but also prevents the performance degradation when the network is congested. These results give us new understanding in the effectiveness of the opportunistic routing. We then analyze and uncover reasons for these results and propose some specific schemes.

This paper introduces danger theory in artificial immune system as a method of responding to danger in wireless mesh networks. It identifies the challenges in deploying Wireless Mesh networks (WMNs) and focus on secure routing as one of the key challenges in deploying WMNs. In order to implement a secure routing system, various Artificial Immune System (AIS) models were analysed. These models have been used in Intrusion Detection System (IDS) and computer security in the literature. In this paper, the authors propose to use Danger models to secure routing in WMNs. The first step in secure routing process is to identify and classify the network dangers and take necessary actions to overcome those dangers. For the classification task, we apply Self-organizing Maps (SOMs) as the classifier to classify the danger levels in WMNs. These identified danger conditions are further deployed as the warning signals for the design of secure routing protocol. The experimental results validate the proposal of applying the Danger Theory (DT) into security area and good performance is also reported by the use of Artificial Neural Network (ANN) classifier.

Opportunistic Routing (OR) has been proposed to improve the efficiency of unicast protocols in wireless networks. In contrast to traditional routing, instead of preselecting a single specific node to be the next-hop forwarder, an ordered set of nodes (referred to as candidates) is selected as the next-hop potential forwarders. In this paper, we propose a new multicast routing protocol based on OR for wireless mesh networks, named Multicast OR Protocol (MORP).We compare our proposal with the well known ODMRP Multicast protocol. Our results show that Multicast-OR outperforms ODMRP, reducing the number of transmissions and increasing the packet delivery ratio.

Interference makes it difficult for a wireless network to provide robust performance and could sometimes lead to transient failures. Dynamic channel switching (DCS) allows a wireless network interface (NIC) to operate in different frequency channels during different time periods without disrupting network connections that traverse the NIC. DCS enables a wireless mesh network to avoid frequency channels with serious interference in certain parts of its coverage area by switching to more idle channels. Although DCS provides additional radio agility, it significantly increases the complexity of the wireless mesh network's routing protocol. This paper describes the design, implementation and evaluation of a wireless mesh network system called Carlsbad, which supports both DCS and load-balancing/fault-tolerant routing, and successfully runs on low-cost commodity IEEE 802.11-based access points. Performance experiments on the first Carlsbad prototype show that despite the additional overhead it introduces, DCS can indeed improve the overall throughput of an IEEE 802.11-based wireless mesh network, sometimes by a factor of more than 2, for both TCP and UDP connections.

Wireless technology has become an essential part of this era’s human life and has the capability of connecting virtually to any place within the universe. A mesh network is a self healing wireless network, built through a number of distributed and redundant nodes to support variety of applications and provide reliability. Similarly, anycasting is an important service that might be used for a variety of applications. In this paper we have studied anycast routing in the wireless mesh networks and the anycast traffic from the gateway to the mesh network having multiple anycast groups. We have also studied the geocast traffic in which the packets reach to the group head via unicast traffic and then are broadcasted inside the group. Moreover, we have studied the intergroup communication between different anycast groups. The review of the related literature shows that no one has considered anycasting and geocasting from gateway to the mesh network while considering the multiple anycast groups and intergroup communication. The network is modeled, simulated and analyzed for its various parameters using OMNET++ simulator.

Nowadays there are inexpensive WiFi devices that have fostered the deployment of wireless communities. Well known routing protocols used in the Internet do not fit well to time varying characteristic of wireless networks. This has motivated an intensive research on routing protocols for wireless mesh networks. At this time there are a number of mature and stable implementations that are being deployed in production networks. In this paper we focus on the experimental evaluation of a production Wireless Mesh network being deployed in a testbed at Universitat Politecnica de Catalunya (UPC) and a quarter of the city of Barcelona, Spain. To our best knowledge, this is the first paper where a production community wireless network using 802.11an is analyzed.

Routing is a critical component in wireless mesh networks. The inherent shared-medium nature of the wireless mesh networks, however, poses fundamental challenges to the design of effective routing policies that are optimal with respect to the resource utilization. Node churns and traffic fluctuations exacerbate such a problem. In this paper, we propose a novel adaptive routing algorithm for multiple subscribers in wireless mesh networks. We view a mesh network with multiple nodes as an entity that optimizes some global utility function constrained by the underlying MAC layer interference. By solving the optimization problem, the network is driven to an efficient operating point with a certain routing policies for each node. We then use this operating point information to adaptively find better paths, which is able to gear the network towards optimal routing. Further, we take the fluctuations of the network into consideration and thus render our algorithm more robust for a variety of network situations. Simulations demonstrate the efficiency and efficacy of our algorithm.

Wireless mesh networks (WMN) are believed to be a highly promising technology and will play an increasingly important role in future generation wireless mobile networks. Routing in WMN is a challenging problem as a result of highly dynamic topology as well as bandwidth and energy constraints. The swarm intelligence paradigm, such as ant colony optimization (ACO), has recently been demonstrated as an active approach for routing in both wired and wireless networks. We designed a novel ACO-based multicasting routing algorithm. In the proposed algorithm, a source-based approach is adapted to build a multicast tree among all the multicast members, and an evolutional scheme for the original multicast tree is designed to find a more optimal multicast tree. In addition the evolutional scheme also acts as a local recovery technique when some intermediate nodes move away. Compared with ODMRP and MAODV, the proposed algorithm performs better in terms of average delay, success ratio and efficiency.