IEEE 802.11b/g 무선 메쉬 네트워크를 위한 클러스터 기반 채널 할당 알고리즘

차시호(Si-Ho Cha),류민우(Min-Woo Ryu),조국현(Kuk-Hyun Cho),조민호(Minho Jo) 대한전자공학회 2009 電子工學會論文誌-CI (Computer and Information) Vol.46 No.4

무선 메쉬 네트워크(Wireless Mesh Networks, WMNs)는 유비쿼터스 환경 및 무선 브로드밴드 액세스를 제공하기 위한 핵심적인 미래 기술로 대두되고 있다. WMN에서의 전체적인 성능은 채널의 간섭을 최소화함으로써 개선될 수 있다. WMN에서 주로 사용하는 네트워크 인터페이스 기술 중 하나인 IEEE 802.11b/g 스펙은 3 개의 멀티채널을 지원한다. 이러한 멀티채널 WMN에서 효율적인 채널 할당을 위해서는 채널 스캐닝 지연과 채널 의존성 문제를 고려해야 한다. 본 논문에서는 IEEE 802.11b/g WMN에서의 이러한 문제점들을 해결하기 위해 클러스터 기반의 채널 할당(Cluster-Based Channel Assignment, CB-CA) 알고리즘을 제안한다. CB-CA 알고리즘에서는 클러스터 헤드(Cluster Head, CH) 노드들 간에는 동일 채널을 사용함으로써 채널 스캐닝과 채널 스위칭을 수행하지 않는다. 해당 클러스터 멤버 (Cluster Member, CM) 노드들과의 통신에는 CH들 간의 통신 채널에 영향을 미치지 않는 채널을 할당함으로써 멀티채널에서 발생할 수 있는 간섭을 최소화 할 수 있다. 시뮬레이션 결과 본 논문에서 제안한 CB-CA 알고리즘이 WMNs의 성능을 향상시킬 수 있음을 입증하였다. Wireless mesh networks (WMNs) are emerging techNoogies that provide ubiquitous environments and wireless broadband access. The aggregate capacity of WMNs can be improved by minimizing the effect of channel interference. The IEEE 802.11b/g standard which is mainly used for the network interface techNoogy in WMNs provides 3 multiple channels. We must consider the channel scanning delay and the channel dependency problem to effectively assign channels in like these multi-channel WMNs. This paper proposes a cluster-based channel assignment (CB-CA) algorithm for multi-channel WMNs to solve such problems. The CB-CA does not perform the channel scanning and the channel switching through assigning co-channel to the inter-cluster head (CH) links. In the CB-CA, the communication between the CH and cluster member (CM) nodes uses a channel has no effect on channels being used by the inter-CH links. Therefore, the CB-CA can minimize the interference within multi-channel environments. Our simulation results show that CB-CA can improve the performance of WMNs.

멀티채널 무선 메쉬 네트워크에서의 채널 그룹을 이용한 거리 기반 채널 할당

김석형(Sok-Hyong Kim),서영주(Young-Joo Suh) 한국통신학회 2008 韓國通信學會論文誌 Vol.33 No.12B

무선 메쉬 네트워크 (Wireless Mesh Network, WMN)는 최근 들어 무선 접속 네트워크에서 높은 네트워크 용량을 지원하기 위해 중요한 이슈로 대두되고 있다. WMN에서 주로 사용하는 네트워크 인터페이스 기술인 IEEE 802.11 표준에서는 IEEE 802.11b/g 또는 IEEE 802.11a와 같은 스펙에 따라 3개 또는 12개의 멀티채널을 지원한다. 하지만, WMN에서 채널 할당 알고리즘을 디자인 할 때 두 가지 중요한 문제, 즉 채널 의존성 문제와 채널 스캐닝 딜레이를 고려해야 한다. 채널 의존성 문제는 인터페이스의 동적인 채널 변경이 노드 연결성을 유지하기 위해 다른 인터페이스의 채널 변경을 일으키는 문제이다. 또한, 채널 스캐닝 딜레이는 인터페이스가 채널을 변경할 때마다 발생하며 성능에 영향을 미친다. 따라서, 본 논문에서는 멀티채널 WMN환경에서 이러한 문제점들을 위해 메쉬 게이트웨이로부터의 거리에 기반한 채널 할당 (Distance-Based Channel Assignment, DB-CA)을 제안한다. DB-CA에서는 서로 다른 채널을 사용하는 노드들이 통신을 하기 위해 채널 스캐닝을 수행하지 않고 오직 채널 스위칭만 수행하며, WMN의 메쉬 게이트웨이에 가까운 노드들이 사용하는 채널에 미칠 수 있는 간섭을 최소화 한다. 실험 결과를 통해 WMN 에서 DB-CA가 기존 채널 할당 방식에 비해 향상된 성능을 나타냄을 확인하였다. Wireless Mesh Networks (WMNs) have recently become a hot issue to support high link capacity in wireless access networks. The IEEE 802.11 standard which is mainly used for the network interface technology in WMNs supports up to 3 or 12 multiple channels according to the IEEE 802.11 specification. However, two important problems must be addressed when we design a channel assignment algorithm: channel dependency problem and channel scanning delay. The former occurs when the dynamic channel switching of an interface leads to the channel switching of other interfaces to maintain node connectivity. The latter happens per channel switching of the interface, and affects the network performance. Therefore, in this paper, we propose the Distance-Based Channel Assignment (DB-CA) scheme for multi-channel WMNs to solve such problems. In DB-CA, nodes just perform channel switching without channel scanning to communicate with neighboring nodes that operate on different channels. Furthermore, DB-CA minimizes the interference of channels being used by nodes near the gateway in WMNs. Our simulation results show that DB-CA achieves improved performance in WMNs.

다중-인터페이스를 갖는 애드 혹 무선 네트워크에서 채널 혼잡도를 이용한 다중-채널 스위칭 프로토콜

임헌주,정수경,이성화,박인갑,Lim, Hunju,Joung, Sookyoung,Lee, Sungwha,Park, Inkap 한국인터넷방송통신학회 2013 한국인터넷방송통신학회 논문지 Vol.13 No.5

다중-인터페이스 기반 네트워크에서 각 노드에 장착된 다수의 무선 인터페이스들을 효율적으로 활용하기 위해서는 각 인터페이스에 이용 가능한 채널들을 적절하게 할당하여 간섭을 감소시키고 대역폭 효율을 높이는 채널 할당 기법이 필요하다. 혼합 할당 방식을 사용하여 네트워크 용량과 처리량을 개선하는 MCS 프로토콜이 제안되었다. MCS는 경쟁 영역 내에서 동일한 채널을 사용하는 노드들의 수를 고정 인터페이스의 채널을 할당하기 위한 기준으로 사용한다. 그러나 이 정보는 실질적으로 채널에 부과되는 부하를 정확히 반영할 수 없는 문제점이 있다. 본 논문에서는 간섭 영역 내에서 동일한 채널을 사용하는 노드들의 수뿐만 아니라 노드들에 의해서 채널이 점유되어 있는 비율을 나타내는 채널 혼잡도를 채널의 부하를 평가하기 위한 기준으로 사용하여 채널을 할당하는 CAMCS 프로토콜을 제안하고 시뮬레이션을 통해서 성능 개선 효과를 확인한다. In network based on multi-interface, there are needed channel assignment strategy that reduce interference and improve bandwidth efficiency by assigning each interface to available channels in order to utilize effectively multiple wireless interfaces on each node. MCS protocol had been proposed, which improve capacity and throughput of network by using hybrid assignment. MCS uses as the criterion to assign channel the number of node that use the same channel in contention area. but there have an problem that this information exactly does not reflect actually offered channel load. in this paper, we proposes CAMCS protocol to assign channel by that the channel busy degree to indicate the occupancy rate of channel by nodes as well as the number of nodes that use the same channel in inference area is used as criterion for estimation channel load, and conform performance improvement effect by simulation.

멀티 라디오 멀티 채널 무선 메쉬 네트워크를 위한 클러스터 기반 최소 간섭 채널 할당

차시호,류민우,조국현 (사)디지털산업정보학회 2010 디지털산업정보학회논문지 Vol.6 No.3

Total performance is improved by minimizing the channel interference between links in wireless mesh networks (WMNs). The paper refines on the CB-CA [1] to be suitable for multi-radio multi-channel (MRMC) WMNs. The CB-CA is the cluster-based channel assignment algorithm for one radio three channel WMN based on IEEE 802.11b/g. The CB-CA does not perform the channel scanning and the channel switching between the cluster heads (CHs) and the edge gateway nodes (EGs). However, the use of co-channel for links between CHs and EGs brings the problem of channel interference among many nodes. We propose and evaluate an improved CB-CA algorithm to solve this problem in MRMC WMNs. The proposed algorithm discriminates between transmission channel and receive channel and assigns channels to each interface randomly and advertises this information to neighbor clusters in order to be assigned no-interference channel between clusters. Therefore, the proposed algorithm can minimize the interference between clusters and also improve QoS, since it can use multiple interfaces and multiple channels.

State-Aware Re-configuration Model for Multi-Radio Wireless Mesh Networks

( Omar M. Zakaria ),( Aisha-hassan Abdalla Hashim ),( Wan Haslina Hassan ),( Othman Omran Khalifa ),( Mohammad Azram ),( Shidrokh Goudarzi ),( Lalitha Bhavani Jivanadham ),( Mahdi Zareei ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.1

Joint channel assignment and routing is a well-known problem in multi-radio wireless mesh networks for which optimal configurations is required to optimize the overall throughput and fairness. However, other objectives need to be considered in order to provide a high quality service to network users when it deployed with high traffic dynamic. In this paper, we propose a re-configuration optimization model that optimizes the network throughput in addition to reducing the disruption to the mesh clients` traffic due to the re-configuration process. In this multi-objective optimization model, four objective functions are proposed to be minimized namely maximum link-channel utilization, network average contention, channel re-assignment cost, and re-routing cost. The latter two objectives focus on reducing the re-configuration overhead. This is to reduce the amount of disrupted traffic due to the channel switching and path re-routing resulted from applying the new configuration. In order to adapt to traffic dynamics in the network which might be caused by many factors i.e. users` mobility, a centralized heuristic re-configuration algorithm called State-Aware Joint Routing and Channel Assignment (SA-JRCA) is proposed in this research based on our re-configuration model. The proposed algorithm re-assigns channels to radios and re-configures flows` routes with aim of achieving a tradeoff between maximizing the network throughput and minimizing the re-configuration overhead. The ns-2 simulator is used as simulation tool and various metrics are evaluated. These metrics include channel-link utilization, channel re-assignment cost, re-routing cost, throughput, and delay. Simulation results show the good performance of SA-JRCA in term of packet delivery ratio, aggregated throughput and re-configuration overhead. It also shows higher stability to the traffic variation in comparison with other compared algorithms which suffer from performance degradation when high traffic dynamics is applied.

채널할당을 위한 진화프로그램과 FEA 혼합 방법

김성수,차영민,민승기 강원대학교 정보통신연구소 2003 정보통신논문지 Vol.7 No.-

There is a continuously growing demand for usable channels that are necessary for communication between mobile users and the base stations of cellular radio networks. However, the number of usable channels is very limited. The objective of this paper is to develop a hybrid method of evolution program(EP) and frequency exhaustive assignment(FEA) for the NP-hard channel-assignment problems to find an optimal channel assignment for minimum interference among the channels within a limited time.

Capacity Improvement with Dynamic Channel Assignment and Reuse Partitioning in Cellular Systems

Chen Steven Li,Chong Peter Han Joo The Korea Institute of Information and Commucation 2006 Journal of communications and networks Vol.8 No.1

In cellular mobile communications, how to achieve optimum system capacity with limited frequency spectrum is one of the main research issues. Many dynamic channel assignment (DCA) schemes have been proposed and studied to allocate the channels more efficiently, thus, the capacity of cellular systems is improved. Reuse partitioning (RP) is another technique to achieve higher capacity by reducing the overall reuse distance. In this paper, we present a network-based DCA scheme with the implementation of RP technique, namely dynamic reuse partitioning with interference information (DRP-WI). The scheme aims to minimize the effect of assigned channels on the availability of channels for use in the interfering cells and to reduce their overall reuse distances. The performance of DRP-WI is measured in terms of blocking probability and system capacity. Simulation results have confirmed the effectiveness of DRP-WI scheme. Under both uniform and non-uniform traffic distributions, DRP-WI exhibits outstanding performance in improving the system capacity. It can provide about 100% capacity improvement as compared to conventional fixed channel assignment scheme with 70 system channels.

Artificial Neural Network with Firefly Algorithm-Based Collaborative Spectrum Sensing in Cognitive Radio Networks

Velmurugan. S,P.Ezhumalai,E.A. Mary Anita 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.7

Recent advances in Cognitive Radio Networks (CRN) have elevated them to the status of a critical instrument for overcoming spectrum limits and achieving severe future wireless communication requirements. Collaborative spectrum sensing is presented for efficient channel selection because spectrum sensing is an essential part of CRNs. This study presents an innovative cooperative spectrum sensing (CSS) model that is built on the Firefly Algorithm (FA), as well as machine learning artificial neural networks (ANN). This system makes use of user grouping strategies to improve detection performance dramatically while lowering collaboration costs. Cooperative sensing wasn't used until after cognitive radio users had been correctly identified using energy data samples and an ANN model. Cooperative sensing strategies produce a user base that is either secure, requires less effort, or is faultless. The suggested method's purpose is to choose the best transmission channel. Clustering is utilized by the suggested ANN-FA model to reduce spectrum sensing inaccuracy. The transmission channel that has the highest weight is chosen by employing the method that has been provided for computing channel weight. The proposed ANN-FA model computes channel weight based on three sets of input parameters: PU utilization, CR count, and channel capacity. Using an improved evolutionary algorithm, the key principles of the ANN-FA scheme are optimized to boost the overall efficiency of the CRN channel selection technique. This study proposes the Artificial Neural Network with Firefly Algorithm (ANN-FA) for cognitive radio networks to overcome the obstacles. This proposed work focuses primarily on sensing the optimal secondary user channel and reducing the spectrum handoff delay in wireless networks. Several benchmark functions are utilized We analyze the efficacy of this innovative strategy by evaluating its performance. The performance of ANN-FA is 22.72 percent more robust and effective than that of the other metaheuristic algorithm, according to experimental findings.The proposed ANN-FA model is simulated using the NS2 simulator, The results are evaluated in terms of average interference ratio, spectrum opportunity utilization, three metrics are measured: packet delivery ratio (PDR), end-to-end delay, and end-to-average throughput for a variety of different CRs found in the network.

Fair and Collision-Aware Multi-Channel Assignment Based on Game Theory for Wireless Multi-Hop Networks

KIM, Hyun-Ki,OH, Chang-Yeong,LEE, Tae-Jin The Institute of Electronics, Information and Comm 2009 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.92 No.4

<P>Equipping wireless routers with multiple radios further improves the capacity by transmitting over multiple radios simultaneously using orthogonal channels. Efficient channel assignment schemes can greatly alleviate the interference effect of nearby transmissions. One of the distinctive features in wireless multi-hop networks is the lack of any central controller, in which each node makes its own decisions. Therefore, fully cooperative behaviors, such as cooperation for increasing link capacity, alleviating interferences for one another, might not be directly applied. In this paper, we aim to present some applications to show how such a framework can be invoked to design efficient channel assignment algorithms in a non-cooperative, topology-blind environment as well as in environments where the competing players share perfect information about channel usage and topology environment and so on. Simulation results are presented to illustrate the effectiveness of the algorithms.</P>

A Dynamic Channel Allocation Algorithm Based on Time Constraints in Cellular Mobile Networks

Lee, Seong-Hoon,Lee, Sang-Gu Korean Institute of Intelligent Systems 2003 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.3 No.1

The new realtime applications like multimedia and realtime services in a wireless network will be dramatically increased. However, many realtime services of mobile hosts in a cell cannot be continued because of insufficiency of useful channels. Conventional channel assignment approaches didn't properly consider the problem to serve realtime applications in a cell. This paper proposes a new realtime channel assignment algorithm based on time constraint analysis of channel requests. The proposed algorithm dynamically borrows available channels from neighboring cells. It also supports a smooth handoff which continuously serves realtime applications of the mobile hosts.