Rozprawy doktorskie na temat „Channel assignment”
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Shepherd, Mark. "Radio channel assignment". Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288047.
Pełny tekst źródłaGerke, Stefanie. "Weighted colouring and channel assignment". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325977.
Pełny tekst źródłaNaveed, Anjum Computer Science & Engineering Faculty of Engineering UNSW. "Channel assignment in multi-radio multi-channel wireless mesh networks". Awarded by:University of New South Wales. Computer Science & Engineering, 2008. http://handle.unsw.edu.au/1959.4/41500.
Pełny tekst źródłaGiortzis, Athanasios. "Channel assignment in mobile radio networks". Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266017.
Pełny tekst źródłaChong, Peter H. J. "Channel assignment schemes in cellular communication systems". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/NQ56660.pdf.
Pełny tekst źródłaAmiri, Nehzad Maryam. "Channel assignment protocols for multi-radio multi-channel wireless mesh netwworks". Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/104156.
Pełny tekst źródłaChiu, Hon-sun, i 邵漢新. "Channel assignment and routing in multi-channel multi-interface wireless networks". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42182050.
Pełny tekst źródłaChiu, Hon-sun. "Channel assignment and routing in multi-channel multi-interface wireless networks". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42182050.
Pełny tekst źródłaGrace, David. "Distributed Dynamic Channel Assignment for the wireless environment". Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288041.
Pełny tekst źródłaDu, Peng. "Bandwidth allocation and channel assignment in WiMax mesh networks /". access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-cs-b30082547f.pdf.
Pełny tekst źródła"Submitted to Department of Computer Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves 100-108)
Zheng, Zhihua, i 鄭智華. "Dynamic channel assignment for cellular mobile radio communication systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31246333.
Pełny tekst źródłaIrwin, Ryan. "Traffic-Aware Channel Assignment for Multi-Transceiver Wireless Networks". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/26601.
Pełny tekst źródłaPh. D.
He, Jingyi. "Routing and channel assignment in optical and wireless networks /". View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20HE.
Pełny tekst źródłaShzu-Juraschek, Felix. "Distributed channel assignment for interference-aware wireless mesh networks". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2014. http://dx.doi.org/10.18452/16957.
Pełny tekst źródłaDue to the broadcast nature of the shared medium, wireless transmissions are potentially received by all network stations in the communication range of the sender. With an unsynchronized medium access, multiple transmissions may be active at the same time and thus interfere with each other. In consequence, multiple transmissions may collide at the receiver side and cannot be properly decoded. For this reason, protocols have been developed on the MAC layer to synchronize the medium access and thus reduce interference effects. One of these approaches in wireless mesh networks is channel assignment. The idea of channel assignment is to minimize the network-wide interference by utilizing non-overlapping channels for otherwise interfering wireless transmissions. This is feasible, since wireless mesh routers are usually equipped with multiple radios and commonly used wireless network technologies, such as IEEE 802.11, provide multiple non-overlapping channels. Since IEEE 802.11 operates in the unlicensed frequency spectrum, the dense distribution of private and commercial network deployments of WLANs in urban areas poses a new challenge. Co-located networks compete for the wireless medium, thus decreasing the achievable network performance in terms of throughput and latency. Therefore, an important issue for efficient channel assignment is to also address external interference The contributions of this dissertation comprise the design, implementation, and validation of models and algorithms to enable wireless multi-hop networks to become interference-aware. This includes a measurement-based interference model suitable for large-scale network deployments. A distributed channel assignment algorithm has been developed that considers external sources of interference. The overall solution has been experimentally validated in a large-scale wireless multi-hop multi-radio testbed and has significantly increased the network performance with regard to the network capacity.
Choi, Sangil. "Minimum interference channel assignment for multicast in multi-channel multi-radio wireless mesh networks". [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1468073.
Pełny tekst źródłaGonzález, Barrameda José Andrés. "Search Space Analysis and Efficient Channel Assignment Solutions for Multi-interface Multi-channel Wireless Networks". Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20155.
Pełny tekst źródłaShah, Ibrar Ali. "Channel assignment and routing in cooperative and competitive wireless mesh networks". Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/6568.
Pełny tekst źródłaWentzell, Tania E. "Lower bounds from tile covers for the channel assignment problem". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0021/MQ49463.pdf.
Pełny tekst źródłaWong, Chi-Fai. "CACAO : client-assisted channel assignment optimization for uncoordinated home WLANs /". View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CSED%202007%20WONG.
Pełny tekst źródłaWeston, Claire L. "Constraint models for multiple interference in the channel assignment problem". Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/55996/.
Pełny tekst źródłaAl-Khaled, Fahad Sulaiman. "Efficient radio channel assignment techniques for mobile satellite communication networks". Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391293.
Pełny tekst źródłaWang, Baobing. "Topology control and channel assignment in wireless multi-hop networks /". access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?mphil-cs-b2375087xf.pdf.
Pełny tekst źródła"Submitted to Department of Computer Science in partial fulfillment of the requirements for the degree of Master of Philosophy." Includes bibliographical references (leaves 60-64)
Ahuja, Sandeep Kour. "ALGORITHMS FOR ROUTING AND CHANNEL ASSIGNMENT IN WIRELESS INFRASTRUCTURE NETWORKS". Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195190.
Pełny tekst źródłaLi, Xiaoguang. "Channel Switching Control Policy for Wireless Mesh Networks". Master's thesis, Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/164788.
Pełny tekst źródłaM.S.
Dynamic channel assignment algorithms allow wireless nodes to switch channels when their traffic loads exceed certain thresholds. These thresholds represent estimations of their throughput capacities. Unfortunately, the threshold estimation may not be accurate due to co-channel interference (CCI) and adjacent-channel interference (ACI), especially with high traffic loads in dense networks. When the link capacity is over-estimated, these channel assignment algorithms are not effective. This is because channel switch is not triggered even with overloaded data traffic and the link quality decreases significantly as the channel is overloaded. When the link capacity is under-estimated, the link is under utilized. Moreover, when link traffic load increases from time to time, channel switch occurs frequently. Such frequent channel switches increase latency and degrade throughput, and can even cause network wide channel oscillations. In this paper, we propose a novel threshold-based control system, called \emph{balanced control system} (BCS). The proposed threshold-based control policy consist of deciding, according to the real time traffic load and interference, whether to switch to another channel,{which channel should be switched to and how to perform the switch. Our control model is based on a fuzzy logic control. The threshold which assists to make the channel switch decisions, could be deduced dynamically according to the real-time traffic of each node. We also design a novel dynamic channel assignment scheme, which is used for the selection of the new channel. The channel switch scheduler is provided to perform channel-switch processing for sender and receiver over enhanced routing protocols. We implement our system in NS2, and the simulation results show that with our proposed system, the performance improves by 12.3\%-72.8\% in throughput and reduces 23.2\%-52.3\% in latency.
Temple University--Theses
Kakumanu, Sandeep. "Component Based Channel Assignment in Single Radio, Multichannel Ad hoc Networks". Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19870.
Pełny tekst źródłaTenneti, Shivaram Venkata. "Channel assignment for throughput improvement in multi-radio wireless mesh networks". Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/tenneti/TennetiS1207.pdf.
Pełny tekst źródłaKundu, Titir. "Exploring Capture Effect for Efficient Channel Assignment in Wireless Sensor Network". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439309020.
Pełny tekst źródłaPark, Sangtae. "Optimal Access Point Selection and Channel Assignment in IEEE 802.11 Networks". Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4687/.
Pełny tekst źródłaFRAIHA, SERGIO LUIZ NORONHA. "ANALYSIS OF THE PROBLEM OF TRAFFIC CHANNEL ASSIGNMENT IN MOBILE CELLULAR SYSTEMS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1996. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8955@1.
Pełny tekst źródłaEste trabalho aborda o problema da alocação dos canais de tráfego em sistemas móveis celulares. A utilização de métodos de alocação mais eficientes constitui uma das principais alternativas para a melhoria do desempenho de sistemas congestionados. Além disto, a constante redução do tamanho das células exige a aplicação de métodos mais flexíveis no que diz respeito ao pré-planejamento das freqüências. Alguns dos inúmeros métodos já propostos são apresentados, e dois deles - CBWL e Segregação de Canais - são simulados em um sistema FDMA micro-celular-uni- dimensional. É feita uma comparação do desempenho oferecido por estes dois métodos, e os resultados obtidos indicam a necessidade da utilização de alguma estratégia de prioridade para o atendimento das solicitações de handoff.
In this work the problem of traffic channel assignment in móbile cellular systems is adressed. The use of more efficient assignment methods represents one of the main alternatives to enhance the performance of congested systems. Moreover, the ceaseless reduction of cell sizes requires the adoption of more flexible methods already proposed are presented, and two of them - CBWL and Channel Segregation - are simulated in FDMA 1-dimensional microcellular system. The performance offered by these two methods is compared, and the results indicate the need of using some priority strategy for attending handoff requests.
Chen, Tai Chun, i 陳泰均. "An Optimal Channel Assignment Algorithm". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/86675405311240095921.
Pełny tekst źródła國立臺北大學
電機工程研究所
98
This thesis presents an optimal channel assignment algorithm based on the famous Left-Edge Algorithm (LEA) and the data structure of buckets for printed circuit boards, electronic design automation, and scheduling. Meanwhile, this algorithm can be applied to channel assignment with the minimal number of tracks. The time and space complexities are both O(N) ,where N is the number of trunks.
Chung, Yi-Fang, i 鍾依芳. "Distributed Channel Assignment in Multi-channel Wireless Mesh Network". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/78916500809284034399.
Pełny tekst źródła國立臺灣大學
資訊工程學研究所
99
In IEEE 802.11, channel resources are very limited and scarce. Thus channel assignment schemes which can effectively utilize available channels is one of the important issues in multi-channel wireless mesh networks. There are two approaches for channel assignment: centralized and distributed. We focus on distributed channel assignment, i.e., each node chooses its channel based on local information. The advantages of distributed approach are better flexibility and fault-tolerance. However, the problem of distributed channel assignment is channel oscillation which results that the channel assignment cannot converge for a long time and nodes change its channel repeatedly, and therefore the network throughput is throttled. In this thesis, we propose a new distributed channel assignment scheme to solve the channel oscillation problem, and to maximize the network throughput. Performance evaluation shows that our proposed algorithm improves the throughput and end-to-end delay in comparison to previously proposed distributed channel assignment schemes.
Lin, Chi-Wen, i 林啟文. "Channel Assignment Strategy in Cellular Network". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/06108476275660350125.
Pełny tekst źródła銘傳大學
資訊管理學系碩士在職專班
90
Department of Information Management Ming Chuan University Abstract With an increasing demand for wireless communication services and the limitation of channel bandwidth, the channel assignment becomes crucial. This paper presents an efficient channel assignment scheme for improving spatial frequency—spectrum reuse in a wireless network with heterogeneous demands, in which each cell has different channel demand. The proposed strategy can be further divided to two strategies, the homogeneous strategy and the inhomogeneous strategy. The homogeneous strategy, based on the distance-k model, is applied to assign channels when most of cells has channel requirement. When the channel requirement of most cells has been satisfied, the inhomogeneous scheme then is utilized. Moreover, the Neural-networks are employed to determine if the channel requirement is sparse. Simulation results show that the proposed scheme is better than previous schemes.
Hung, Shih-Jia, i 洪世嘉. "On Channel Assignment Of Regular Graphs". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/84175782045294494603.
Pełny tekst źródła國立嘉義大學
資訊工程學系研究所(Graduate School of Computer Scie
98
The channel assignment problem which was modeled by graphs was introduced by Hale in 1980. They used the vertices to denote the transmitters and the edges to indicate two transmitters being “very closed”. A k-L(2,1) labeling f for a given graph G=(V,E), is a function f:V→{0,1,2,...,k} such that for every pair of vertices x, y in V, |f(x)-f(y)|>=2 if d(x,y)=1, and |f(x)-f(y)|>=1 if d(x,y)=2 where d(x,y) denotes the distance between vertices x and y. The channel assignment problem can be solved by finding the minimum k such that G has a k-L(2,1) labeling. This thesis established the bounds of L(2,1) labeling, for some regular graphs such as star-like, pancake, burnt pancake, folded hypercube,locally twisted cube, and twisted N-cube graph.
Chiang, Yueh-Yiing, i 蔣岳穎. "Channel assignment in mobile communication systems". Thesis, 1991. http://ndltd.ncl.edu.tw/handle/18747524935326992249.
Pełny tekst źródłaLiang, Yi-An, i 梁逸安. "Distributed Flexible Channel Assignment in WLANs". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/41500499129730453969.
Pełny tekst źródła國立臺灣大學
資訊工程學研究所
100
Abstract Flexible channel enable access points and clients to use one pair of several channel widths and center frequencies to transmmit packets. Using different channel widths will bring each link different transmmision throughputs and tranmission ranges. The channel assignment in the WLANs will be more flexible and the throughput of the system will improve. In this thesis we introduce a distributed flexible channel assignment algorithm called DFCA. In DFCA, each link decides the channel width and center frequency based on the transmmission weight, channel width, center frequency and interference relation of neiboring nodes. Every link will choose the channel width and center frequency greedily which can bring it the highest throughput and consequently improve the total throughput of the system. We compared our DFCA algorithm with other fixed channel width and flexible channel width channel assignment algorithms in the total throughput of the system on the network simulaor NS-2. FLUID, one of our compared flexible channel assignment algorithms, is a complete research about flexible channel in recent years. FLUID uses a central controller to manage the per-packet scheduling and assign each packet a pair of channel width and center frequency used to transmmit the packet. According to the simulation result on NS-2, DFCA can reach at least 90% in throughput compared to the FLUID.
Lo, Kuen-Rong, i 羅坤榮. "Channel Assignment Schemes for Hierarchical Cellular Systems". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/84177540136138851638.
Pełny tekst źródła國立交通大學
電子工程系
88
In this dissertation, channel assignment schemes of hierarchical cellular systems with overlaying macrocells and overlaid microcells are studied. First, a combined channel assignment (CCA) mechanism is proposed. The objective of the proposed CCA mechanism is to reduce the new-call blocking probability, decrease forced termination probability, and increase the channel utilization for the whole system. The proposed CCA mechanism combines overflow, underflow, and reversible schemes to reduce both the new-call blocking probability and forced termination probability. Also, it adopts the buffering scheme and considers load balancing between macrocell and microcell to obtain a high channel utilization. Next, a novel scheme, a fuzzy channel allocation controller (FCAC), is proposed for hierarchical cellular systems. The objective of the proposed FCAC scheme is to increase the channel utilization for the whole system and to guarantee the required QoS of handoffs as well. The FCAC mainly contains a fuzzy channel allocation processor (FCAP) which is designed to be in a two-layer architecture: a fuzzy admission threshold estimator in the first layer and a fuzzy channel allocator in the second layer. The FCAP chooses the handoff failure probability, defined as quality-of-service (QoS) index, and the resource availability as input linguistic variables for the fuzzy admission threshold estimator. The Sugeno''s position-gradient type reasoning method is applied in the fuzzy admission threshold estimator to adaptively adjust the admission threshold for the fuzzy channel allocator. For achieving channel allocation with flexible admission and soft rate control, a neural fuzzy channel allocation controller (NFCAC) is designed for multimedia services in hierarchical cellular system. The design concept of NFCAC is to support flexible resource allocation and soft rate control so that the high blocking rate in a hierarchical cellular system providing multi-channel services can be reduced. The NFCAC mainly contains a neural fuzzy channel allocation processor (NFCAP) which is designed to be in a two-layer architecture that consists of a fuzzy channel selector (FCS) in the first layer and a neural fuzzy call-admission and rate controller (NFCRC) in the second layer. FCS is a fuzzy control logic, and it can properly determine which channel in either macrocell or microcell to be allocated. The NFCRC is a five-layer neural fuzzy controller with the reinforcement learning architecture to perform the flexible admission control and soft rate management. 2. Hierarchical Cellular Systems 3. A Combined Channel Assignment Mechanism 4. A QoS-Guaranteed Fuzzy Channel Allocation Controller 5. A Neural Fuzzy Channel Allocation Controller for Multimedia Services 6. Conclusions
Chen, Chih-Jen, i 陳至仁. "Genetic Algorithms for Channel Assignment in PCS". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/69522928725215801693.
Pełny tekst źródłaLee, Ming-Hsi, i 李明羲. "Adaptive Channel Assignment Scheme for Wireless Networks". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/35125111400168946673.
Pełny tekst źródła銘傳大學
資訊管理研究所
89
In this paper, an adaptive channel assignment scheme is proposed to ensure the quality of services for the wireless networks. The proposed scheme based on the FCA (fixed channel assignment) strategy divides the channels into two categories, the guard channels and the shared channels. The number of guard channels is estimated by the Markov Model. The shared channels can be used by both new calls and handoff calls. This new scheme based on the fuzzy process can allocate most guard channels to the handoff calls and few to the new calls. In addition, the proposed scheme provides a load balance method for balancing the channel utilization between adjacent cells. From the simulation, the proposed scheme significantly improves the drop rate and the block rate in comparison with the existing methods.
Deora, Sanjeev K. "Channel assignment algorithms in cellular radio networks". Thesis, 1995. https://thesis.library.caltech.edu/3587/1/Deora_sk_1995.pdf.
Pełny tekst źródłaWu, Chih-Jen, i 鄔智仁. "A HIERARCHICAL CLUSTERING CHANNEL ASSIGNMENT SCHEME FOR MULTI-CHANNEL WIRELESS NETWORKS". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/01402476635845315673.
Pełny tekst źródła國立清華大學
通訊工程研究所
94
Channel assignment is an important issue in high throughput multi-channel wireless networks. Previous works on channel assignment use a common control channel to negotiate data channels by exchanging RTS/CTS. However, these schemes require time synchronous mechanism for starting to negotiation in each contention window, which is hard to achieve in wireless networks. Moreover, the above negotiation-based scheme may incur the channel switching delay during channel assignment in each hop of a multi-hop communication. In this paper, we propose an asynchronous scheme for channel assignment based on clustering all nodes in a wireless network into a hierarchical clustering architecture. With the hierarchical clustering architecture, our scheme can elect the cluster head of highest level and allocates channels by the cluster head of highest level to all leaves in a level-by-level basis. Simulation results show that the proposed channel assignment scheme outperforms the negotiation-based schemes in terms of packet collision, end-to-end delay, and overall throughput.
Huang, Wun-Yuan, i 黃文源. "Channel Assignment Study for Multi-Channel Multi-Radio Wireless Mesh Networks". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/03868574855987716539.
Pełny tekst źródła國立東華大學
資訊工程學系
97
With the popularity and development of networks in recent years, the wireless network has become an important research topic. Most research efforts on this area are to improve the performance of wireless network, particularly using multiple channels. While traditional wireless networks use single channel, there is no way to carry out many simultaneous transmission links at the same time, but multi-channel networks can solve the problem. However, there are some problems when using multi-channels. These problems are the interference and split problems. The split problems can be solved by using of multiple radios. The interference problem is a hot topic that lots of researchers try to solve. This paper focused on the architecture of the wireless mesh networks. The main research issue is how to improve network performance under multi-channel and multi-radio environments. We have to consider the interference problem for having good performance. There should be a good channel assignment mechanism to avoid interference. There are two types of methods on channel assignment: distributed channel assignment and centralized channel assignment. The difference between them is that when using the distributed channel assignment nodes decide which channel to use by themselves, but there is a controller in the centralized channel assignment. Our research focused on the centralized channel assignment. In this paper, three different centralized channel assignment algorithms were mentioned: 1. Load-aware channel assignment, 2. Coloring based load-aware channel assignment, and 3. Hybrid channel assignment. These three methods are compared in the multi-channel and multi-radio system under the architecture of the wireless mesh network. We use the NS2 network simulation tool to perform our experiments. We compare these three algorithms in terms of packet loss rate, end-to-end delay, and throughput.
Ko, Hsu-Feng, i 柯旭峰. "An Interference-Aware Channel Assignment Strategyin Multi-Radio Wireless Mesh NetworksAn Interference-Aware Channel Assignment Strategyin Multi-Radio Wireless Mesh NetworksAn Interference-Aware Channel Assignment Strategy in Multi-Radio Wireless Mesh". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/92623274949977330122.
Pełny tekst źródła國立高雄應用科技大學
資訊工程系
97
Next-generation wireless communication technologies will make life more convenient. The wireless mesh networks evolved into a key technology in wireless communication development. The wireless mesh networks can quickly increase the coverage of wireless service. While single radio mesh nodes operating on single channel suffer from interference. Because more and more demand for wireless networks, wireless interference is becoming more and more serious. Interference of overlapping channel maybe leads to packet loss. Multi-radio mesh node using non-overlapping channel can significantly alleviate the interference problem and increase the aggregate bandwidth available to the network, but spectrum is scarce that interference impact remains in multi-radio wireless mesh networks. However, the assignment of channel to the radio poses significant challenges in the scarce spectrum. The goal of channel assignment strategy is to minimize interference and improve network performance. In this article we analyzed interference impact and traffic patterns that designed an interference-aware channel assignment strategy called ICAS. ICAS incorporates interference impact and traffic pattern issues in order to assign adaptive channel to multi-radio wireless mesh networks.
Chan, Hsuan-Hao, i 詹烜皓. "Rate-Adaption Channel Assignment and Routing Algorithm forMulti-Channel WirelessMAN Mesh Networks". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/65vm8a.
Pełny tekst źródła國立中央大學
資訊工程研究所
94
Wireless mesh networks provide an easy deployed and extensi- ble solution to access Internet or communicate with each other for both enterprises and individuals. With the help of multi-channel and multi- radio, wireless mesh network can support more tra¢ c load to meet higher and higher bandwidth requirement in this modern time. There have been researches that focus on channel assignment and routing al- gorithm for IEEE 802.11 multi-channel environment to achieve better network throughout. However, the data rate and transmission range of 802.11 is limited and is not suitable for a large area metropolitan mesh network deployment. This thesis presents a rate-adaption chan- nel assignment and routing algorithm for IEEE 802.16 multi-channel multi-radio network in mesh mode which is expected as the last-mile wireless broadband connectivity. We takes 802.16 TDMA characteris- tic and modulation/rate adaption into consideration. The Simulation results show that our channel assignment procedure uses fewer chan- nels and better channel utilization than the migrated 802.11 greedy approach. Among the three comparing routing protocols, our protocol performs better in multi-rate 802.16 mesh network and results in higher aggregate throughput.
Hsu, Kun-Jin, i 許坤進. "Channel Assignment and Performance Evaluation of directional Multi-Channel Wireless Mesh Networks". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/99337367505530116796.
Pełny tekst źródła國立臺灣大學
資訊管理學研究所
93
IEEE provides non-overlapping channels for multiple transmissions to transmit at the same time. But most IEEE 802.11-based networks today use only a single channel. As a result, these networks can’t exploit the peak performance because of packet collision and interference. In this thesis, we study the interference problems including hidden terminal problem and exposed terminal problem in wireless mesh networks. We proposed a new architecture of directional multi-channel wireless mesh networks and TwoHop channel assignment algorithm. Compared to the single-channel network, we only revise the systematic procedure to support the multi-channel transmission with multiple network interface cards to transmit at the same time. Using our channel assignment algorithm to assign channels on links can lower the interference problems in wireless LANs and improve the network overall received goodput. We verify the performance improvement of the proposed algorithm through ns2. From the result, our approaches indeed improve the network performance and the success rate of the long route packets.
Liu, Pei-Shiun, i 呂佩勳. "A Channel Assignment Scheme for Concentric-Hexagon based Multi-Channel Wireless Networks". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/94059459556904430042.
Pełny tekst źródła東海大學
資訊工程學系
98
In a wireless network environment, a multi-hop communication performed on a single channel may lead to hidden node and radio signal interference problems which are also the key reasons why network transmission efficiency is often not as expected. In fact, the hidden node problem is caused by radio signal interference, i.e., the key reason is signal interference. Currently, many studies have used multi-channel schemes to solve the single channel interference problem. Multi-channel can increase the network capacity. But it raises other problems, e.g., multi-channel hidden terminal problem and how to allocate channels to wireless nodes so that interference problem can be avoided and transmission performance can be significantly improved. Basically, a well-defined channel assignment algorithm can solve the problems. Therefore, in this study, we proposed an AP deployment scheme, called concentric-hexagon-oriented multi-channel assignment (CHOMA for short) which supports multi-channel mechanism and is suitable for use in a metropolitan-scale wireless network system. With this scheme, the deployed APs are arranged as concentric-hexagon (C-hexa for short), and available channels are grouped and allocated to the C-hexas. We also schedule channels allocated to a C-hexa so as to reduce radio interference among its APs, consequentially improving the transmission capability and performance of a wireless network.
Chun-Kit, Ng, i 吳俊傑. "Channel-Aware Fairness Scheduling in WiMAX Downlink Assignment". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/36444865823585358416.
Pełny tekst źródłaChen, Wen-Jiang, i 陳文江. "Researches on Channel Assignment Schemes for Cellular Systems". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/72250434909172210252.
Pełny tekst źródła國立中正大學
電機工程研究所
83
For cellular Time Division Multiple Access (TDMA), channel assignment algorithm is one of the most crucial techniques in increasing system capacity and radio spectrum utilization efficiency. Traditional analog Frequency Division Multiple Access(FDMA) Systems, e.g. AMPS, adopted central-controlled prediction-based fixed channel assignment while the second generation TDMA systems, e.g. PACS, DECT, adopt disbibuted measurement-based dynamic channel assignment and directed retry techniques. Conversation quality is also an important performance measure in addition to system capacity and spectrum utilization. In this thesis, in order to take into account both factors of system capacity and coversation quality, we define a performance measure, Grade Of Service (GOS), to assess the performance of various systems. In this thesis, we set up a TDMA cellular frequency reuse system by using BONeS (Block Oriented Network Simulator) simulation tool. Based on this simulation system, we first investigate several distributed measurement-based channel selection algorithms in fixed channel assignment system. Besides, a new method with adaptive threshold concept is presented to improve the performance of these channel selection algqorithms. Next, we study the performance of directed retry and load sharing techniques. Finally, a new algorithm called hybrid time-slot selection is proposed to improve the system performance.
Sun, Ming Hong, i 孫銘鴻. "Improved Dynamic Channel Assignment Scheme -Using Factor Graph". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/13051555986901810241.
Pełny tekst źródła長庚大學
電機工程學系
98
In order to enhance the frequency reuse factor and therefore increase the system throughput, the base station of wireless communication system use antenna array with multiple antennas to sector its cell coverage so that multiple in-cell users can share the same channel resources, including frequency spectra and time slots. In this study, we use the factor graph to serve the purpose of dynamic channel assignment. The sum-product algorithm is adopted to pass the messages of channel assignment in the factor graph constructed by the base stations and the mobile stations of a wireless cellular network. This study is fundamentally an improved approach of the original work proposed by Chen[1]. As compared to Chen’s previous work, in this study we propose a two-stage method to perform the channel assignment. In the first stage, the proposed approach first assigns channel to the nearest mobile station in each sector. After the first round distance-based channel assignment, in the second stage, the remaining un-assigned in-cell mobile stations will be taken to form the variable nodes of the factor graph and then their channel availability will be determined by the sum-product algorithm. As compared to Chen’s work, the proposed approach possesses lower channel blocking rate and significantly reduced computational overheads.
Chich, Cheng Tseng, i 曾志成. "The Study of Channel Assignment Strtegies in Microcellular". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/09795344389656047950.
Pełny tekst źródła國立台灣工業技術學院
電子工程技術研究所
85
In this thesis, we consider a seven-cell microcellular mobile communication system to study its channel assignment strategies. In order to check if a call generated in neighboring cells will be handed off to the target cell, we define the handoff region as a rectangular about cell boundaries. From this definition, the time that handoff calls stay in this region, i.e. dwell time, can also be computed. The distribution of dwell time obtained in this thesis shows that the exponential distribution assumption in previous works is not reasonable. For the study of channel assignment strategies with handoff in microcellular mobile communication networks, both the preemptive and non- preemptive disciplines are employed in the double queue model and the single queue model. The basic concept of channel assignment strategy we used is borrowed from the fixed channel assignment with guard channels. The impacts of emergency calls on the system performance are also considered by using guard channels. We observe the variation of the blocking probability of general calls, emergency calls and the forced termination probability of handoff calls by changing the number of emergency guard channels and handoff guard channels. As to the preemptive service discipline, we define the dropping probability as the probability for ongoing general calls being preempted by emergency calls which find no available channels upon arrival. Two cost functions are defined to compute the costs of different schemes. We compare the performance of the above schemes with that of the FIFO scheme and the results show that the single queue with preemptive scheme is a better channel assignment strategy than the other schemes.
Lai, Chang-Cheng, i 賴昌成. "Adaptive Channel Assignment Scheme for Wireless Cellular Networks". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/88982174673842521793.
Pełny tekst źródła國立東華大學
資訊工程學系
87
Abstract Because the radio spectrum is limited, how to manage the limited spectrum is an important issue since before. When radio spectrum is divided into channels, the way to manage spectrum is called channel assignment management. When channel assignment strategies are compared based on the manner in which co-channels are separated, they can be divided into Fixed Channel Assignment (FCA), Dynamic Channel Assignment (DCA), and Hybrid Channel Assignment (HCA). FCA performs well under heavy traffic load, DCA performs well under light traffic load, and HCA is suited to moderate traffic load. In this research we propose a new HCA scheme which takes advantage of all three schemes to reach the best performance, and the new HCA scheme is consisted kinds of channel assignment schemes. In our research the new call blocking probability and handoff call blocking probability are referred to as the performance indices. The first determines the fraction of new calls that are blocked, while the second is the fraction of admitted calls that terminate prematurely due to dropout. We use an analytical method to do the performance measurement, and the wireless cellular system is modeled as a multi-dimensional Markov chain under appropriate statistical assumptions. In fact from the point of view of a subscriber we prefer to block a new call request rather than block a handoff call request, so we include the handoff priority methods to our proposed HCA scheme. Our proposed HCA scheme has the lowest average new call and handoff call blocking probabilities because it takes advantage of the existing channel assignment schemes. Besides the analytical model, we also propose a transition mechanism of channel assignment schemes according to the analytical results. Keywords: Channel Assignment Scheme, Fixed Channel Assignment, Dynamic Channel Assignment, Hybrid Channel Assignment, Wireless Cellular Networks, Markov Chain