Channel Assignment Scheme Research Articles

Distributed Channel Assignment Algorithm Based on Traffic Awareness in Wireless Mesh Networks

Recently, wireless mesh network (WMN) technology recently has been used in various industries. Especially, a number of multi-channel assignment schemes have been presented to improve the throughput of IEEE 802.11-based multi-hop WMN. However, performance of the conventional multi-channel assignment schemes is not enough to satisfy the industry requirements. We, thus, should study more about the multi-channel assignment scheme in order to enhance the performance. This paper proposes a novel channel assignment scheme that employs multi-channel and multi-Interface in the WMN. The proposed scheme obtains the traffic information of the network and does the efficient channel assignment without any message exchanges. We verify the efficiency of the proposed scheme through the mathematical modeling and the real-world experiments. The results show that the proposed scheme improves the throughput of the network compared with the conventional schemes.

Cognitive channel selection and scheduling for multi-channel dynamic spectrum access networks considering QoS levels

Dynamic spectrum access (DSA) networks are composed of unprivileged users, called secondary users (SUs), that utilize the spectrum opportunities produced by the absence of co-located privileged primary users (PUs) via their cognitive capabilities. Providing a certain level of quality of service (QoS) to these users is a very challenging problem whilst providing protection to licensed PUs and contenting with nearby SUs. Even though centralized solutions may lead to better solutions in terms of network efficiency, the dynamic nature of DSA networks make the distributed solution approaches more attractive. In this paper, we present a fast, distributed, PU temporal-activity-estimation-aided spectrum assignment scheme for a multi-channel DSA system, including several multi-interface capable SUs with traffic demands at differentiated QoS levels. We first developed the proposed cognitive channel selection method, considering a simplified network having single channel and investigated its performance. Second, considering multi-channel environment, along with contending multi-SUs each of which can utilize multiple channels using their multi-interface property, we adopted the designed algorithm and coupled the proposed spectrum selection scheme with a distributed spectrum sharing mechanism that we devised to increase the overall network utility further. We modeled our scheme along with the network model using MATLAB® and evaluated its performance via several simulations. The extensive simulations validate the effectiveness of the proposed channel assignment scheme in terms of the Figure of Merit we defined, composed of the weighted sum of the throughput ratio values for packets of different QoS levels that successfully reached at the destination. The results also show the superior performance of the proposed scheme with respect to a native scheme that utilizes every spectrum opportunity in favor of the most demanding traffic flow.

A multi-cell graph based dynamic resource allocation scheme for multi-user wireless networks

Dynamic resource allocation being a computationally difficult problem, static spectrum management is more commonly used in large-scale networks. The combination of virtualization technologies, where powerful centralized allocation algorithms can be implemented, and recent advances in graph coloring algorithms prompts the revisiting of this view. We describe a new graph based framework to maximize the number of simultaneously communicating mobiles in a wireless network. Since the considered problem is NP-hard, we propose various heuristic algorithms and analyze their performance, in comparison with standard decentralized channel assignment strategies such as Fractional Frequency Reuse (FFR). We consider the LTE uplink and downlink with the WINNER channel as the reference model. We show that for blocking probabilities below 2%, our scheme typically increases the number of mobile users by 25%. For example with 25 base stations and 120 channels, running the resource allocation scheme takes one second on a PC and permits to increase the number of mobiles requiring one single channel each from 750 to 950, a 25% increase in efficiency compared to FFR.

A Fast Channel Assignment Scheme for Emergency Handling in Wireless Body Area Networks.

Ubiquitous healthcare is a promising technology that has attracted significant attention in recent years; this has led to the realization of wireless body area networks (WBANs). For designing a robust WBAN system, the WBAN has to solve the drawbacks of wireless technology. Also, a WBAN has to support immediate, reliable data transmission for medical services during emergencies. Hence, this study proposes a new MAC superframe structure that can handle emergencies by delivering strongly correlated regular data to a caretaker, within a certain time threshold. Simulation results demonstrate that the proposed MAC protocol achieves low latency and high throughput.

Link quality aware channel allocation for multichannel body sensor networks

Body Sensor Network (BSN) is a typical Internet-of-Things (IoT) application for personalized health care. It consists of economically powered, wireless and implanted medical monitoring sensor nodes, which are designed to continually collect the medical information of the target patients. Multichannel is often used in BSNs to reduce the spectrum competition of the tremendous sensor nodes and the problem of channel assignment has attracted much research attention. The health sensing data in BSNs is often required to be delivered to a sink node (or server) before a certain deadline for real time monitoring or health emergency alarm. Therefore, deadline is of significant importance for multichannel allocation and scheduling. The existing works, though designed to meet the deadline, often overlook the impact of the unreliable wireless links. As a result, the health sensing data can still be overdue because of the scheduled lossy links. Besides, potential collisions in the schedules also incur considerable delay in delivering the sensing data. In this paper, we propose a novel deadline-driven Link quality Aware Channel Assignment scheme (LACA), where link quality, deadlines and collisions are jointly considered. LACA prioritizes links with urgent deadlines and heavy collisions. Besides, LACA allows the exploitation of the spare slots for retransmissions on lossy links, which can further reduce the retransmission delay. Extensive simulation experiments show that compared to the existing approaches, LACA can better utilize the wireless spectrum and achieve higher packet delivery ratio before the deadline.

Topology Controlled Channel Assignment Scheme with Power Control in MRMC Wireless Mesh Networks

Topology Controlled Channel Assignment Scheme with Power Control in MRMC Wireless Mesh Networks

A cross-layer optimization framework for joint channel assignment and multicast routing in multi-channel multi-radio wireless mesh networks

ABSTRACTExisting literature on multicast routing protocols in wireless mesh networks (WMNs) from the view point of the links involved in routing are divided into two categories: schemes are aimed at multicast construction with minimal interference which is known as NP hard problem. In contrast, other methods develop network-coding-based solutions with the main objective of throughput maximization, which can effectively reduce the complexity of finding the optimal routing solution from exponential to polynomial time. The proposed framework in this paper is placed in the second category. In multi-channel multi-radio WMNs (MCMR WMNs), each node is equipped with multiple radios, each tuned on a different channel. In this paper, for the first time, we propose a cross-layer convex optimization framework for joint channel assignment and multicast throughput maximization in MCMR WMNs. The proposed method is composed of two phases: in the first phase, using cellular learning automata, channels are assigned to the links established between the radios of the nodes in a distributed fashion such that the minimal interference coefficient for each link is provided. Then, the resultant channel assignment scheme is utilized in the second phase for throughput maximization within an iterative optimization framework based on Lagrange relaxation and primal problem decomposition. We have conducted many experiments to contrast the performance of our solution against many representative approaches.

Joint multicast routing and channel assignment for multi-radio multi-channel wireless mesh networks with hybrid traffic

In this paper, joint multicast routing and channel assignment problem in wireless mesh networks (WMNs) with hybrid traffic is investigated. Previous works design routing and channel assignment schemes for WMNs with single multicast session, however, resource usage is optimized for only one multicast session in this case and overall network load balance is left out of consideration. This may result in high congestion in some links, while others are underutilized. In this paper, multicast routing and channel assignment problem is solved from traffic management perspective by introducing load balance. Programming formulation is formulated to obtain the optimal results which can be used as benchmark to evaluate other schemes. Multicast weighted conflict graph is designed to model partially overlapped channels (POCs) interference in hybrid traffic scene. It regards links originating from the same node as one transmission to fully exploit wireless broadcast advantage; it uses link weight to measure interference degree and gives full consideration to interference characteristics of POCs. A heuristic multicast routing and channel assignment scheme based on multicast weighted conflict graph is designed to solve the joint problem, and simulation results show that the heuristic scheme can reduce network interference and improve WMNs service capability while dramatically reducing computational complexity.

A survey on security vulnerabilities in channel assignment algorithms of multi‐interface wireless mesh networks

AbstractWireless mesh network (WMN) has been deployed as a key and progressing technology all around the world to provide the end‐to‐end users with high quality of service. Regarding of its major design concern as network throughput, WMN has been evolved based on multi‐channel multi‐radio strategy to make simultaneous transmissions possible. The advent of this significant improvement has introduced other challenging issues such as channel assignment (CA). Its core strategy applied in multi‐radio multi‐channel WMNs to promote achievable capacity using properly mapping the available channels to the radio interfaces. Although, in recent years, there are a number of research studies on CA's improvement, there are some security drawbacks that should be addressed. Most of CA schemes assume all nodes involved in CA techniques are trustworthy. This unrealistic assumption and misbehavior of those nodes makes the network susceptible to various security attacks which lead to performance degradation. This paper presents an in‐depth survey of the CA's attacks as well as detection or prevention mechanism found in the literature. The attacks are classified into two groups: attacks imposed by the malicious neighbor as well as by the assigner or the assignee. In addition, a comparative and analytical discussion is provided on current solutions and their open problems. According to conducted analysis, the current knowledge gap leading to most of these attacks is lack of accurate verification because of implicit trust in nodes in CA procedure. Although, there are some research studies proposing kinds of case‐specific verification, they cannot close the gap properly, and there is a need to comprehensive approach. Finally, reviewing state‐of‐the‐art of related works shows, there are more possible attacks such as collusion or multistage attacks that have not taken into account so far. Copyright © 2016 John Wiley & Sons, Ltd.

Evaluation of a channel assignment scheme in mobile network systems

AbstractThe channel assignment problem is a complex problem which requires that under certain constraints a minimum number of channels have to be assigned to mobile calls in the wireless mobile system. In this paper, we propose a new scheme, which is based on double band frequency and channel borrowing strategy. The proposed scheme takes into account factors such as limited bandwidth of wireless networks and the capacity of underlying servers involved in processing mobile calls. It aims to ensure end-to-end performance by considering the characteristics of mobile devices. This is achieved by determining the position of users (or mobile stations) in wireless mobile systems. The proposed scheme is simulated in order to investigate its efficiency within a specific area of a large city in Saudi Arabia. Experimental results demonstrate that the proposed scheme significantly improves the performance of mobile calls as well as reduces the blocking when the number of mobile call increases.

Content-Based Multi-Channel Network Coding Algorithm in the Millimeter-Wave Sensor Network.

With the development of wireless technology, the widespread use of 5G is already an irreversible trend, and millimeter-wave sensor networks are becoming more and more common. However, due to the high degree of complexity and bandwidth bottlenecks, the millimeter-wave sensor network still faces numerous problems. In this paper, we propose a novel content-based multi-channel network coding algorithm, which uses the functions of data fusion, multi-channel and network coding to improve the data transmission; the algorithm is referred to as content-based multi-channel network coding (CMNC). The CMNC algorithm provides a fusion-driven model based on the Dempster-Shafer (D-S) evidence theory to classify the sensor nodes into different classes according to the data content. By using the result of the classification, the CMNC algorithm also provides the channel assignment strategy and uses network coding to further improve the quality of data transmission in the millimeter-wave sensor network. Extensive simulations are carried out and compared to other methods. Our simulation results show that the proposed CMNC algorithm can effectively improve the quality of data transmission and has better performance than the compared methods.

Multi-Cluster based Dynamic Channel Assignment for Dense Femtocell Networks

This paper proposes a novel channel assignment scheme called multi-cluster based dynamic channel assignment (MC-DCA) to improve system performance for the downlink of dense femtocell networks (DFNs) based on orthogonal frequency division multiple access (OFDMA) and frequency division duplexing (FDD). In order to dynamically assign channels for femtocell access points (FAPs), the MC-DCA scheme uses a heuristic method that consists of two steps: one is a multiple cluster assignment step to group FAPs using graph coloring algorithm with some extensions, while the other is a dynamic subchannel assignment step to allocate subchannels for maximizing the system capacity. Through simulations, we first find optimum parameters of the multiple FAP clustering to maximize the system capacity and then evaluate system performance in terms of the mean FAP capacity, unsatisfied femtocell user equipment (FUE) probability, and mean FAP power consumption for data transmission based on a given FUE traffic load. As a result, the MC-DCA scheme outperforms other schemes in two different DFN environments for commercial and office buildings.

Partially overlapped channels- and flow-based end-to-end channel assignment for multi-radio multi-channel wireless mesh networks

Capacity reduction is a major problem faced by wireless mesh networks. An efficient way to alleviate this problem is proper channel assignment. Current end-toend channel assignment schemes usually focus on the case where channels in distinct frequency bands are assigned to mesh access and backbone, but actually backbone network and access network can use the same IEEE 802.11 technology. Besides, these channel assignment schemes only utilize orthogonal channels to perform channel assignment, and the resulting network interference dramatically degrades network performance. Moreover, Internet-oriented traffic is considered only, and peer-to-peer traffic is omitted, or vice versa. The traffic type does not match the practical network. In this paper, we explore how to exploit partially overlapped channels to perform end-to-end channel assignment in order to achieve effective end-to-end flow transmissions. The proposed flow-based end-to-end channel assignment schemes can conquer the limitations aforementioned. Simulations reveal that loadaware channel assignment can be applied to networks with stable traffic load, and it can achieve near-optimal performance; Traffic-irrelevant channel assignment is suitable for networks with frequent change of traffic load, and it can achieve good balance between performance and overhead. Also, partially overlapped channels' capability of improving network performance is situation-dependent, they should be used carefully.

Effective dynamic channel assignment scheme for on‐board processing satellite platform

Dynamic channel assignment is an effective approach to decrease inter-cell interference and improve link quality. Due to flat beam coverage property, link performance is degraded if conventional dynamic channel assignment schemes are directly employed in satellite network. To solve this problem, this study proposes the beam cooperation based dynamic channel assignment scheme, in which adjacent beams serve edge users cooperatively. Feature of feed sharing, channel model of satellite network, number of cooperative beams and combination method of the receiver are discussed in the proposed scheme. In addition, link quality restriction is applied to avoid drastically performance degradation in case of heavy traffic. Simulation results show that the proposed dynamic channel assignment scheme can effectively improve the average performance of users in the beam. Furthermore, the optimal antenna parameter for the proposed scheme is achieved by simulation.

Four Channel Assignment Schemes for WiFi in 2.4 GHz Band

Nowadays, WiFi is mostly operating in 2.4 GHz band, which allows only 3 non-overlapping channels. For deployment in building it could be a problem to repeat only three channels. In this paper we compare standard three channel scheme (channels 1, 6 and 11) with four channel schemes. The most promising scheme is with channels 1, 5, 9 and 13, which involves overlapping channels, but the overlap is minimal and in certain distances (power levels) is possible to use this scheme. The problem could be in some countries which do not allow usage of 13 channels. We also compare other schemes, with overlapping channels, but they have a much lower throughput than scheme with channels 1, 5, 9 and 13.

Constructive algorithms for the partial directed weighted improper coloring problem

Given a complete directed graph G with weights on the vertices and on the arcs, a θ-improper k-coloring is an assignment of at most k different colors to the vertices of G such that the weight of every vertex v is greater, by a given factor 1/θ, than the sum of the weights on the arcs (u,v) entering v with the tail u of the same color as v. For a given real number θ and an integer k, the Partial Directed Weigthed Improper Coloring Problem (PDWICP) is to determine the order of the largest induced subgraph G′ of G such that G′ admits a θ-improper k-coloring. This problem is motivated by a practical channel assignment application where the objective is to maximize the number of simultaneously communicating mobiles in a wireless network. We consider three constructive algorithms for the standard vertex coloring problem, and adapt them to the PDWICP. We show that they perform better than today's phone operator systems based on decentralized channel assignment strategies such as fractional frequency reuse.

A fast channel assignment scheme based on power control in wireless ultraviolet networks

The Ultraviolet (UV) Non-line-of-sight (NOLS) communications are becoming a research hotspot in recent years. For wireless UV networks, there are some well-known existing issues such as network connectivity, power control and channel assignment. In this paper, a Fast Power Control and Channel Assignment scheme (FPCCA) is proposed to reduce interference and save energy. Firstly, the FPCCA is compared with the traditional channel assignment which without power control. It is proved that the approach of FPCCA can save energy more than 10%. Then, the FPCCA is both applied in the UV and Wireless Mesh Networks (WMN). The performance of FPCCA with different angles and network traffic loads is simulated and analyzed. When the traffic load is fixed, the performance metrics of FPCCA in UV are better than that in WMN. Meanwhile, the FPCCA not only ensures the quickness and accuracy of channel assignment, but also saves energy and improves the throughput.

Learning Automata Based Channel Assignment with Power Control in Multi-Radio Multi-Channel Wireless Mesh Networks

Wireless channel assignment is one of the major challenging issues in multi hop wireless mesh networks (WMN) when there is the need to design them in a distributed fashion, specifically for multi-radio multi-channel (MRMC) systems. In this work, a new learning automata based channel and power assignment scheme which adaptively improve network overall throughput by expecting network dynamics was proposed. First, a utility function which reflected the user’s preference for the signal to interference and noise ratio (SINR) was applied, and then the transmitter power. The distributed channel assignment and power control problem is formulated as a multiple payoff stochastic game of automata. In this game, each user evaluates a channel and power selection strategy by computing a utility value. This evaluation is performed using a stochastic iterative procedure. The utility function that potentially reflected a measure of satisfaction of every node was used by every node as an environmental response for the current selected strategy chosen by the nodes. According to dynamics of system, the proposed algorithm assigned channels and powers to radio interface such that it minimized interference in the neighborhood of a node. The stability of the system was analyzed via appropriate Lyapunov-like trajectory; it was shown that the stability and optimum point of the system converged.

Target-Aware, Transmission Power-Adaptive, and Collision-Free Data Dissemination in Wireless Sensor Networks

Software update in wireless sensor networks requires the ability of disseminating bulk data to specified sensors of a network with low latency in an energy efficient manner. This paper proposes a target-aware, transmission power-adaptive, and collision-free data dissemination protocol to fulfill these requirements. This protocol disseminates data to sensors of a network by first constructing a connected dominating set (CDS) in the network. We propose a target-aware CDS construction to exclude many unnecessary non-target sensors from the data dissemination process. By allowing some dominators of the CDS to increase their transmission power to disseminate data to more dominatees, the protocol efficiently reduces the total energy consumption. In addition, we propose a collision-based channel assignment strategy to eliminate communication collisions among dominators so as to reduce latency. We have implemented the protocol and evaluated it through simulations and a real application scenario. Our experimental results show that the proposed protocol at most reduces non-target sensors by 75.3%, total energy consumption by 57.1%, and latency by 39.8% compared to existing dissemination protocols.

Tree‐based channel assignment schemes for multi‐channel wireless sensor networks

AbstractMany sensor node platforms used for establishing wireless sensor networks (WSNs) can support multiple radio channels for wireless communication. Therefore, rather than using a single radio channel for whole network, multiple channels can be utilized in a sensor network simultaneously to decrease overall network interference, which may help increase the aggregate network throughput and decrease packet collisions and delays. This method, however, requires appropriate schemes to be used for assigning channels to nodes for multi‐channel communication in the network. Because data generated by sensor nodes are usually delivered to the sink node using routing trees, a tree‐based channel assignment scheme is a natural approach for assigning channels in a WSN. We present two fast tree‐based channel assignment schemes (called bottom up channel assignment and neighbor count‐based channel assignment) for multi‐channel WSNs. We also propose a new interference metric that is used by our algorithms in making decisions. We validated and evaluated our proposed schemes via extensive simulation experiments. Our simulation results show that our algorithms can decrease interference in a network, thereby increasing performance, and that our algorithms are good alternatives for static channel assignment in WSNs. Copyright © 2015 John Wiley & Sons, Ltd.