Multi-hop Wireless Communication Research Articles

Low-Latency SINR-Based Data Gathering in Wireless Sensor Networks

Data gathering is a fundamental operation in various applications of wireless sensor networks (WSNs), where sensor nodes sense information and forward data to a sink node via multi-hop wireless communications. Typically, data in a WSN is relayed over a tree topology to the sink for effective data gathering. A number of tree-based data gathering schemes have been proposed in the literature, most of which aim at maximizing network lifetime. However, the timeliness and reliability of gathered data are also of great importance to many applications in WSNs. To achieve low-latency, high-reliability data gathering in WSNs, in this paper, we construct a data gathering tree based on a reliability model, schedule data transmissions for the links on the tree and assign transmitting power to each link accordingly. Since the reliability of a link is highly related to its signal to interference plus noise ratio (SINR), the SINR of all the currently used links on the data gathering tree should be greater than a threshold to guarantee high reliability. We formulate the joint problem of tree construction, link scheduling and power assignment for data gathering into an optimization problem, with the objective of minimizing data gathering latency. We show the problem is NP-hard and divide the problem into two subproblems: Constructing a low-latency data gathering tree; Jointly link scheduling and power assignment for the data gathering tree. We then propose a polynomial heuristic algorithm for each subproblem and conduct extensive simulations to verify the effectiveness of the proposed algorithms. Our simulation results show that the proposed algorithms achieve much lower data gathering latency than existing data gathering strategies while guaranteeing high reliability. Moreover, the algorithms also have a comparable energy efficiency and network lifetime to other algorithms.

On the Capacity of a Wireless Backhaul for the Distribution Level of the Smart Grid

Many application scenarios envisioned as part of the “smarter” grid depend on an effective underlying communication infrastructure for power distribution. The advanced metering infrastructure (AMI) is one such application scenario where bidirectional communication between electric meters of customers and the utility control center is required for demand response and load control. Several technologies have been suggested to meet communication needs for the backhaul that connects customer data collection points with the utility's control center. In this paper, these technologies are compared with a justification of why wireless communication technologies may be most suitable for the backhaul. A linear chain multihop wireless communication architecture is then proposed, and its ability to meet application requirements of the communication backhaul is evaluated through simulations. Based on capacity limitations first seen in the simulation results, a theoretical analysis is done to understand the data carrying capacity of using linear chain wireless technologies for the communication backhaul. Finally, the AMI application scenario is used as a case study to understand the implications of any limitations imposed by the proposed communication architecture.

Enhancing wireless networks with caching: Asymptotic laws, sustainability & trade-offs

We investigate on the sustainability of multihop wireless communications in the context of Information-Centric Networks, when content is replicated in caches over the network. The problem is cast in a flat wireless network for a given content popularity distribution and sized by three parameters, (i) the network size N, (ii) the content volume M and (iii) the cache capacity K per node. The objective is to select a joint replication and delivery scheme that minimizes the link traffic. Assuming the Zipf distribution about the content popularity, a law well established in the research on Internet traffic, we compute an order optimal solution, let the three size parameters jointly scale to infinity, and find the scaling laws about the link rates, ranging from ON down to o(1). Analyzing the derived laws, we determine the regimes that the network becomes sustainable subject to the scaling of the three network size parameters and the Zipf rank exponent, characterize the relative merit of network resources and identify the induced trade-offs about network expansion.

Topology Property Based on Network Tomography for Wireless Mobile Multihop Communication Network

The random movement of nodes makes the dynamic topology structure be one of the most important characteristics in wireless multihop communication network, which makes the description and quantization of the dynamic property the very foundation of the design, simulation, and measurement for this kind of network. The distributions of the link duration and the topology duration will be derived and verified by simulations. Then, the topology flapping sensing method has been put forward based on TTL. Finally, the probability model of the topology stability in the measurement time has been established and calculated based on network tomography for wireless mobile multihop communication network in this paper. Simulating results verify the correctness and efficiency of the approach, which will provide the technique basis of research on the dynamic property and end-to-end measurement for wireless mobile multihop communication network.

Quantum wireless multihop communication based on arbitrary Bell pairs and teleportation

Communication in quantum wireless multihop networks is useful in global quantum networks. We propose a scheme for faithful quantum communication in quantum wireless multihop networks, by performing quantum teleportation between two distant nodes which do not initially share entanglement with each other. The required entanglement among intermediate nodes is established through entanglement swapping based on arbitrary types of Bell pairs. All the measurement outcomes and the types of Bell pairs are sent to the destination node independently. The initial quantum state can be finally recovered by corresponding local operations. Our scheme can reduce end-to-end communication delay by using simultaneous measurements in contrast to the scheme based on sequential entanglement swapping.

On the implementation, deployment and evaluation of a networking protocol for VANETs: The VARON case

Research on vehicular communications has been quite extensive over the past few decades. Most of the initial studies were theoretical and research has just recently moved to more experimental works. Conducting real field operational tests is extremely challenging due to the number of vehicles required, the lack of control over the environment and the cost of the necessary equipment and personnel. However, simulation tools may not reflect properly the highly dynamic and complex characteristics of the vehicular scenario. This article explores why practical research in the field of vehicular communications is so demanding, by reporting on our experience in prototyping and experimentally evaluating VARON. Published in 2008, VARON is a multi-hop wireless vehicular communication protocol which was already validated via extensive simulations. In this work, we have fully implemented it, first on a lab-based environment, and then in a real-life testbed. This long and exhausting process has shown that some common assumptions do not necessarily hold when evaluated under real situations, as well as taught us valuable lessons on how to design and conduct experiments with real vehicles. We believe that the experience and lessons learned during this process do not only apply to VARON, but also to other multi-hop wireless vehicular communication solutions, and that therefore these lessons are helpful for other researchers willing to validate their protocols in a real scenario.

Enhanced Network Coding to Maintain Privacy in Smart Grid Communication

Cyber-physical systems (CPS) are aimed at combining the physical system with the cyber ones to provide a better control and improve the management of physical systems around us. Recently, the CPS and its applications, e.g., health-care and smart grid, have gained attention of the research community. In this paper, we consider the privacy aspect of users in a CPS, particularly in smart grid system as our use-case, and provide a mechanism that utilizes the advances in network coding to maintain data privacy. We address privacy issues associated with gathering metering information of clients in a smart grid system. In smart grid systems, wireless multi-hop communications are mainly used to gather metering information through exchanging data and control messages between smart meters and the utility. We argue that any communication paradigm used in a smart grid should support all aspects of privacy such as anonymity, unlinkability, unobservablity, and undetectablity. We propose innovative schemes for traffic routing and encryption that benefit from the enhanced network coding technology. Our analysis shows that our schemes maintain privacy of users despite the possibility of detecting metering data by an adversary. In addition, our scheme has extra favorable features such as less computation complexity, reliable, and robust communication.

Probabilistic location-free addressing in wireless networks

Multi-hop wireless networks, such as sensor, ad hoc and mesh networks, suffer from permanent topology dynamics due to unstable wireless links and node mobility. Stable addressing, as needed for reliable routing, in such evolving, challenging network conditions is thus a difficult task. Efficient multi-hop wireless communication in these networks then requires a fully decentralized, scalable routable addressing scheme that embraces network dynamics and dynamically recovers from failures.In this paper, we present Probabilistic ADdressing (PAD), a virtual coordinate based addressing mechanism that efficiently deals with dynamic communication links in wireless networks. PAD estimates statistical distributions of hop distances between nodes to (i) assign fuzzy routable regions to nodes instead of discrete addresses, and (ii) provide a distributed storage service to store and retrieve node addresses. We evaluate PAD both in simulations and in widely used testbeds. Our results highlight the graceful topology maintenance and recovery of PAD in challenging networking conditions due to node mobility and unstable link conditions. Precisely, we observe that, when compared with the state-of-the-art, our proposed mechanism achieves an order of magnitude fewer address changes in the network translating into less overhead traffic and high packet success.

GEographic Multicast (GEM) for Dense Wireless Networks: Protocol Design and Performance Analysis

Multicast is necessary in several wireless multihop communication scenarios. Accordingly, it has received a lot of attention in the past, and several multicast protocols have been proposed. Nevertheless, traditional solutions typically incur poor efficiency when there is a large number of nodes, topology changes occur frequently, and/or the traffic load is low. Geographic multicast has been recently exploited to solve the problems mentioned above. However, these solutions require exchange of topology information that, again, can lead to excessive overhead. In this paper, we propose a new geographic multicast protocol denoted as GEM, which is inspired by the Euclidean Steiner Tree (EST) theory and does not require any information exchange for routing purposes. Therefore, it is very efficient and scalable in wireless networking scenarios where other schemes achieve low performance, especially in terms of energy consumption. In this paper, we also derive some key properties of GEM that allow us to characterize the protocol performance. As a major contribution, we show that these properties are quite general and apply to a wide range of algorithms inspired by the EST. Simulation results assess the derived properties and confirm the effectiveness of the proposed GEM scheme.

Mitigating Selfish Behavior in Mobile Ad Hoc Networks: A Survey

Mobile Ad hoc Networks (MANETs) is a collection of mobile nodes forming the network dynamically for exchange of information using the multi-hop wireless communications without the need of any pre-existing infrastructure. The mobile nodes act as hosts as well as router to establish communication among nodes in the network. To achieve high throughput nodes are expected to cooperate with each other in packet forwarding process to enable out of range communication. In MANETs, all the routing protocols are designed with an assumption that the nodes will cooperate in packet forwarding. But the inherent characteristics of MANETs such as no fixed infrastructure, dynamic topology, limited battery power and wireless medium introduces node misbehavior. An individual node may behave selfishly to preserve its scarce resources and do not forward the packets to other nodes but still want to use their services to send and receive their own packets. The selfish behavior affects the performance of the network significantly. Many solutions have been proposed by the researchers to mitigate this selfish behavior. In this paper, we review some of the notable works carried out in mitigating selfish behavior on packet forwarding at the network layer, providing a comprehensive comparison between the different proposed methods.

Efficient authentication for fast handover in wireless mesh networks

We propose new authentication protocols to support fast handover in IEEE 802.11-based wireless mesh networks. The authentication server does not need to be involved in the handover authentication process. Instead, mesh access points directly authenticate mobile clients using tickets, avoiding multi-hop wireless communications in order to minimize the authentication delay. Numerical analysis and simulation results show that the proposed handover authentication protocol significantly outperforms IEEE 802.11 authentication in terms of authentication delay.

Fault Tolerant Control of Multi-Hop Control Networks

A multi-hop control network (MCN) consists of a plant where the communication between sensors, actuators, and computational units is supported by a (wireless) multi-hop communication network, and data flow is performed using scheduling and routing of sensing and actuation data. We address the control design problem on a MCN where the plant is a SISO LTI system and links are subject to permanent failures. We first characterize controllability and observability of a MCN: we provide necessary and sufficient conditions on the plant dynamics and on the communication scheduling, and we provide a design methodology to satisfy such conditions for any failure configuration. Then we address the problem of detecting the failure of links of the radio connectivity graph: we provide necessary and sufficient conditions on the plant dynamics and on the communication protocol, and we provide a design methodology to satisfy the above conditions.

Experiences and Challenges in Deploying OpenFlow over Real Wireless Mesh Networks

Wireless Mesh Networks propose a distributed architecture for establishing quickly, scalable, reliable and ease of maintenance multi-hop wireless communications. However, many wireless mesh network technologies lack of high level services such as handoff and mobility management. Meanwhile, the OpenFlow protocol offers a framework for developing high level services over data networks. OpenFlow is an interface for remotely controlling the flow table of switches, routers and access points. It separates the control and data planes of network devices, while supports a centralized architecture for controlling the forwarding of packets. Extending wireless mesh networks with OpenFlow offers many benefits, as the use of high level services like mobility. Nevertheless, this combination introduces challenges regarding the opposition between the centralized control of OpenFlow and the distributed architecture of wireless mesh networks. In this paper we expose our experiences deploying an OpenFlow controller over a wireless mesh network based on the 802.11s standard. First, we describe the scenarios employed in our testbed. Then, we discuss the considerations for each scenario. Finally, we expose our conclusions regarding the OpenFlow's implementation and its capabilities of supporting throughput-dependant services.

Research on Topology Property for Wireless Multi-hop Communication Network

The random movement of nodes makes the topology structure be one of the most important characteristics in wireless multi-hop communication network, which makes the description and quantization of the dynamic property the very foundation of the design, simulation and measurement for this kind of network. Wireless Ad hoc network as a typical multi-hop network will be focused on in this paper. The distributions of the link duration and the topology duration will be derived and verified by simulations. Then, the topology flapping sensing method has been put forward based on TTL. Finally, the probability model of the topology stability in the measurement time has been established and calculated based on network tomography for wireless ad hoc network in this paper. Simulating results verify the correctness and efficiency of the approach, which will provide the technique basis of research on the dynamic property and end-to-end measurement for wireless multi-hop communication network. DOI: http://dx.doi.org/10.11591/telkomnika.v11i1.1907

Asymptotic Laws for Joint Content Replication and Delivery in Wireless Networks

We investigate on the scalability of multihop wireless communications, a major concern in networking, for the case that users access content replicated across the nodes. In contrast to the standard paradigm of randomly selected communicating pairs, content replication is efficient for certain regimes of file popularity, cache and network size. Our study begins with the detailed joint content replication and delivery problem on a 2D square grid, a hard combinatorial optimization. This is reduced to a simpler problem based on replication density, whose performance is of the same order as the original. Assuming a Zipf popularity law, and letting the size of content and network both go to infinity, we identify the scaling laws and regimes of the required link capacity, ranging from O(\sqrt{N}) down to O(1).

A Fixed Backoff-Time Switching Method for CSMA/CA Protocol in Wireless Mesh Networks

SUMMARY As a flexible and cost-efficient scalable Internet access network, we studied architectures, protocols, and design optimizations of the Wireless Internet-access Mesh NETwork (WIMNET) .W IMNET is composed of multiple access points (APs) connected through multihop wireless communications on IEEE 802.11 standards. The increasing popularity of real-time applications such as IP-phones and IP-TV means that they should be supported in WIMNET. However, the contention resolution mechanism using a random backoff-time in the CSMA/CA protocol of 802.11 standards is not sufficient for handling real-time traffic in multihop wireless communications. In this paper, we propose a Fixed Backoff-time Switching (FBS) method for the CSMA/CA protocol to improve the real-time traffi cp erformance in WIMNET by giving the necessary activation chances to each link. We implement our proposal on the QualNet simulator, and verify its effectiveness through simulations on three network topologies with four scenarios.

Incremental Distributed Construction Method of Delaunay Overlay Network on Detour Overlay Paths

In wide-area disaster situations, wireless mesh networks lose data communication reachability among ar- bitrary pairs of base stations due to the loss of routing information propagation and synchronization. This paper uses a Delaunay overlay approach to propose a distributed networking method in which detour overlay paths are incremen- tally added to a wireless mesh network in wide-area disaster situations. For this purpose, the following functions are added to each base station for wireless multi-hop communication: obtaining the spatial location, exchanging spatial location messages between base stations, transferring data based on spatial locations of base stations. The proposed method always constructs a Delaunay overlay network with detour paths on the condition that a set of wireless links provides a connected graph even if it does not initially provide reachability among arbitrary base stations in the con- nected graph. This is different from the previous method that assumes a connected graph and reachability. This paper therefore also shows a new convergence principle and implementation guidelines that do not interfere with the existing convergence principle. A simulation is then used to evaluate the detour length and table size of the proposed method. It shows that the proposed method has scalability. This scalability provides adaptable low-link quality and increases the number of nodes in wide-area disaster situations.

The Distribution of the Ratio of the Products of Two Independentα-μVariates and Its Application in the Performance Analysis of Relaying Communication Systems

We present novel general, simple, exact, and closed-form expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the ratio of the products of two independentα-μvariates, where all variates have identical values of alpha parameter. Obtained results are applied in analysis of multihop wireless communication systems in different fading transmission environments. The proposed theoretical analysis is also complemented by various graphically presented numerical results.

A Research Paper on Comparison between Energy Efficient Routing Protocol with Energy and Location in MANET

Energy is an important issue in MANET (Mobile Ad hoc Network). Nodes in network are working in presence of limited energy. So, energy efficient routing is needed for reducing energy consumption. Energy efficient routing schemes can greatly reduce energy consumption and extends the lifetime of the networks. Multipath routing protocol (AOMDV) having more than one path, if the first one is break then second provides the proper packet delivery, this causes reduced node energy consumption and the topology of MANETs always changes, due to the high mobility of nodes. This makes it more difficult to find the routes that message packets use when they are routed. The location based routing provides the location information of the destination to route a packet toward. This paper provides comparison and study on reduced energy consumption by using multipath protocol and performance which is evaluated by performance metrics in case of AOMDV and energy based AOMDV. Now here DREAM protocol is used with AOMDV to finding location of mobile nodes but not with energy but here measures their performance with both multipath protocols. I. INTRODUCTION A mobile ad hoc network (MANET) is a dynamic distributed system of mobile formed by means of multi-hop wireless communication without the use of any existing network infrastructure. MANET routing protocols can be classified into two classes. Proactive protocols, they requires the nodes to periodically exchange the table information to update the pre-determine routes between any pair of source destination nodes. Reactive protocols can establish routes only when they require. MANET routing protocols can be classified on the bases of the methods of delivery of data packets from source to destination. Single Path routing protocols learn routes and select a single best route to each destination. These protocols are incapable of load balancing traffic. Multi-path routing protocols learn routes and can select more than one path to a destination. These protocols are better for performing load balancing. This paper provides the comparison between results about Multipath routing in AOMDV (13), AOMDV with location and Energy with AOMDV.

Fault Tolerant Stabilizability of MIMO Multi-Hop Control Networks

A MIMO Multi-hop Control Network (MCN) consists of a MIMO LTI plant where the communication between sensors, actuators and computational units is supported by a (wireless) multi-hop communication network and data flow is performed using scheduling and routing of sensing and actuation data. We explicitly characterize by means of necessary and sufficient conditions the set of network configurations that invalidate controllability and observability of the plant. We show that checking such necessary and sufficient conditions can be solved with a complexity that is combinatorial with respect to the number of input and output signals. To overcome this difficulty, we propose an efficient algorithm to design the network configuration in linear time still guaranteeing controllability and observability.