DART: Directional Anypath Routing in Wireless Mesh Networks

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.

QoS routing in wireless mesh networks (WMNs) is a daunting task. Finding a path for a given flow depends not only on the bandwidth-delay requirements of that flow but also on the available bandwidth of all the nodes in that path and the amount of bandwidth consumption caused by that flow along its path. Contrary to the wired networks, these two parameters are not fixed and depend on the interference pattern of the network that in turn depends on the selected path itself. This converts the QoS routing in wireless mesh networks to a much harder problem. Existing methods use on-demand approach based on flooding of routing packets. This approach does not scale up to large networks. Field-based routing (FBR) is a promising approach to reduce the routing overhead for static route set up. However, it is not previously used for QoS routing. In this paper, we have developed a new FBR based QoS routing protocol for WMNs. Contribution of this paper is two folds. First, a one-pass field-based routing instead of regular two-pass approach is developed that significantly reduces the overhead of distributing routing information and computing the path and increases the QoS delivered to the flows. Secondly, a new routing metric named LU-IR is introduced that is shown to lower intra-flow and inter-flow interferences and results in increased network service capacity. The performance of the proposed algorithm is extensively studied through simulations. The results indicate that average delay of the flows is improved and the network throughput is increased compared to the existing schemes.

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.

Anypath routing has been proposed to improve the performance of unreliable wireless networks by exploiting the spatial diversity and broadcast nature of the wireless medium. In this paper, we focus on anypath routing subject to K constraints, and present a polynomial time K-approximation algorithm. When K = 1, our algorithm is the optimal polynomial time algorithm for the corresponding problem. When K ≥ 2, the corresponding problem is NP-hard. We are the first to present an O(1)-approximation algorithm. Furthermore, our algorithm is as simple as Dijkstra's shortest path algorithm, and is therefore suitable for implementation in actual wireless routing protocols.

The ultimate goal of routing in wireless mesh networks (WMNs) is to find the “good” paths between the source and destination. Considering of the characteristics of this new networking paradigm, such as low mobility and less restriction from the energy effect, the focus is on the design and optimization of the technology to establish the path that can reflect this network feature. In this paper, an efficient routing algorithm is proposed based on decision-making sequence in WMNs, and the routing process is mapped into multi-stage decision process. We construct a mathematical model for it and present a multi-decision sequential routing method taking use of the idea of dynamic programming. In addition, a new metric (EEDT) for routing based on the information of MAC layer in WMNs is given, which optimized the two objectives- end to end delay and throughput. In the end, the multi-decision sequential routing algorithm (MDSR) is proposed that synthesized the suggesting method and new metric. The path selected by MDSR would be better based on the mathematical model, and it has lower delay of routing building. At the same time, EEDT can accurately capture the quality of the network links. Simulation results show that the proposed routing algorithm significantly improves the performance of the WMNs in terms of end-to-end delay and throughput.

QoS routing problem in wireless mesh networks is a NP-complete problem, and it is hard to get the global solution with the traditional algorithm. In this paper, we adopt a novel dynamic ant genetic hybrid algorithm to solve QoS unicast routing problem for wireless mesh network, whose innovation are using the best melting point evaluation strategy to control the calling of the two algorithms dynamically. Simulation results show that the novel algorithm is superior to the genetic algorithm and the static ant genetic hybrid algorithm in quality and efficiency for QoS routing in wireless mesh network.

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.

Field Based Routing (FBR) is the next promising class of routing algorithms especially for wireless mesh networks. The inherent nature of shared medium wireless mesh networks, however, poses fundamental challenges to the design of effective routing policies that are optimal with respect to speed, time and resource utilization. In this paper, globally optimized routing algorithm for multiple subscribers in wireless mesh networks is proposed. Mesh network with multiple nodes will serve as an environment that optimizes some global utility function limited by the mobile nodes position in underlying MAC (Media Access Control) layer. By solving the optimization problem, the network is brought to a point of efficient operation with a certain routing policy for each node. This information will be the operating point that can be used to find better ways adaptive, which is able to steer the network towards the optimal routing. Global optimization of FBR is depicted through path estimation using PSO (Particle Swarm Optimization).

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.

On this paper, we propose a hierarchical routing framework which is adapted to a wireless mesh network (WMN) environment and ensures the most critical issue in the wireless network: load-balancing. We simplify clusters formation and maintenance procedure, propose limited topology broadcasting mechanism allowing WMC to choose the best path to a WMC in adjacent cluster, and connect to a number nearby WMR. Basing on that routing framework we propose a liquid-simulated algorithm to keep load-balances between WMRs.

Wireless mesh networks are popular due to their adaptability, easy-setup, flexibility, cost, and transmission time-reductions. The routing algorithm plays a vital role in transferring the data between the nodes. The network’s performance is significantly impacted by the route opted by the algorithm. The router takes the decision to send the packet to the next router as per the policy of that algorithm. So even though that decision does not favor the right path selection, the router tends to follow its policy. This can be avoided by having intelligent routers that can make routing decisions on the fly. This paper presents the QL-Feed Forward routing algorithm (QFFR), a new generation of routing algorithms that combines reinforcement learning based on the Q-learning algorithm with a Feed Forward neural network. This algorithm (QFFR) can learn from the network environment and make routing decisions based on the algorithm’s learnings. The AI agent’s ability to select the fastest path, which enhances the efficiency of the routing operation, is demonstrated by the working of the suggested QFFR algorithm. This paper also evaluates the performance of traditional algorithms, namely, Ad-hoc On-Demand Distance-Vector, Optimized-Link-State-routing, Destination-Sequenced Distance-Vector and Distance Source routing. The evaluation parameters include throughput, packet delivery ratio, and delay. The parameters are the outcomes of the time the information takes to reach from source to destination. This analysis highlights the improvement in the routing decision ability of a router. As per analysis, Ad hoc On-Demand Distance Vector Algorithm outperforms with throughput 723.13 Kbps, delay 343.73 ns. Q-learning agent identifies the route and reaches the destination in average of 3.7s in non-grid architecture. The Q-learning agent takes 0.49sec with a grid size ten by ten and 0.53sec in three by four grid size. The suggested QFFR takes 7.62s score-over time with stable, consistent performance.

Efficient multicasting over Wireless Mesh Network (WMN) is challenging due to dynamic and multi-hop wireless communication among multicast group members. Multicast Ad hoc On-Demand Distance Vector (MAODV) protocol is a tree based multicast routing protocol that enables dynamic, self-starting, multi-hop routing between participating mobile nodes wishing to join or participate in a multicast group in Wireless Mesh Network (WMN). The mobility of mobile nodes often causes link breakage in the tree-based protocols which sometime results in tree partitioning and poor performance. In MAODV, when a broken link is detected between two nodes on the multicast tree, the node downstream to the break is responsible for initiating the repair of the broken link. After link repair, it is likely that the previous distance between the nodes (nodes downstream to the link breakage) and the group leader will not remain same. The shortest path from the group leader to the nodes downstream to the node which initiates link breakage is not ensured. Moreover, if the node attempting to repair a tree link break does not receive a response after certain attempts, it assumes that the multicast tree is not repairable currently and this leads to tree partitioning. In this paper, an improved link repair technique is proposed which ensures shortest path from any node to the group leader. Simulation results demonstrate significant improvement in performance metrics compared to standard MAODV.

To support reliable multicast routing in wireless mesh networks, it is important to protect multicast sessions against link or node failures. The issue of protecting multicast sessions in wireless mesh networks is a new problem to the best of our knowledge. In this paper, we propose a resilient forwarding mesh approach for protecting a multicast session in wireless mesh networks. Utilizing the wireless broadcast advantage, a resilient forwarding mesh effectively establishes two node disjoint paths for each source-destination pair. This allows a multicast session to be immune from any single link or intermediate node failure. We introduce four heuristic algorithms to obtain approximate solutions that seek to minimize the number of required broadcast transmissions. We evaluate the performance of these heuristic algorithms against the optimal resilient forwarding mesh (ORFM) obtained by solving an integer linear programming (ILP) formulation of the problem. Experimental results demonstrate that one of these heuristic algorithms, which we call the minimal disjoint mesh algorithm (MDM), performs sufficiently close to ORFM. Besides, we find that the resilient forwarding mesh approach provides efficient 1+ 1 protection (Pioro and Medhi, 2004) to the multicast session without incurring much additional overhead on a single minimal cost multicast tree

Reinforcement learning for QoS-guaranteed intelligent routing in Wireless Mesh Networks with heavy traffic load

Voice over IP (VoIP) over a wireless mesh network (WMN) is a killer application candidate of the next generation services over wireless and mobile network infrastructure. Yet, the routing and transport efficiencies in consideration of specific attributes of WMNs have been little emphasized. Distinctively from conventional networks, the major traffic pattern of WMNs is anycast (one-to-one-of-many). To fully utilize the service aspects of WMNs, load balancing and scalability should simultaneously be supported. For VoIP, one challenge is to maintain the perceived quality depending on both loss and delay. In this paper, we assess autonomous load balancing anycast routing regarding VoIP supportability. The protocol is based on physics analogy and a distributed algorithm. We compare the protocol with shortest-path routing and back-pressure routing via simulations. Simulation results exhibit that autonomous load balancing of the protocol efficiently supports voice calls to guarantee the certain level of quality.