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Jin‐Long Wang 《International Journal of Communication Systems》2005,18(6):571-584
This paper presents a new channel assignment scheme that efficiently improves the spatial frequency–spectrum reuse in a wireless network with heterogeneous demands, in which the cells are partitioned into a lot of clusters. Since the channel demands of each cell are different, this scheme adopts two stages to effectively assign channels. In the first stage, the cluster‐based scheme allocates a number of channels to the cells of each cluster for satisfying the requirement of co‐channel reuse. The channel demand of majority cells will be satisfied in this stage. In the second stage, when the channel requirement of most cells has been fulfilled, the tree‐based assignment scheme allocates channels for the minority cells, which are still lacking of channels. Simulation results showed that the proposed scheme is superior to the previous schemes. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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This paper studies scheduling algorithms for an infra-structure based wireless local area network with multiple simultaneous transmission channels. A reservation-based medium access control protocol is assumed where the base station (BS) allocates transmission slots to the system mobile stations based on their requests. Each station is assumed to have a tunable transmitter and tunable receiver. For this network architecture, the scheduling algorithms can be classified into two categories: contiguous and non-contiguous, depending on whether slots are allocated contiguously to the mobile stations. The main objective of the scheduling algorithms is to achieve high channel utility while having low time complexity. In this paper, we propose three scheduling algorithms termed contiguous sorted sequential allocation (CSSA), non-contiguous round robin allocation (NCRRA) and non-contiguous sorted round robin allocation (NCSRRA). Among these, CSSA schedules each station in contiguous mode, while other two algorithms, NCRRA and NCSRRA, schedule stations in non-contiguous mode. Through extensive analysis and simulation, the results demonstrate that the CSSA with only slightly increased complexity can achieve much higher channel utility when compared to the existing contiguous scheduling algorithms. The NCRRA and NCSRRA on the other hand, results in significantly lower complexity, while still achieving the optimal channel utility compared to existing non-contiguous scheduling algorithms. Chonggang Wang received a B.Sc. (honors) degree from Northwestern Polytechnic University, Xi'an, China, in 1996, and M.S. and Ph. D. degrees in communication and information system from University of Electrical Science and Technology in China, Chengdu, China, and Beijing University of Posts and Telecommunications, Beijing, China, in 1999 and 2002, respectively. From September 2002 to November 2003 he has been with the Hong Kong University of Science and Technology, Hong Kong, where he is an associate researcher in the Department of Computer Science. He is now a post-doctoral research fellow in University of Arkansas, Arkansas. His current research interests are in wireless networks with QoS guarantee, sensor networks, peer-to-peer and overlay networks. Bo Li received the B.S. (summa cum laude) and M.S. degrees in the Computer Science from Tsinghua University, Beijing, P. R. China, in 1987 and 1989, respectively, and the Ph.D. degree in the Electrical and Computer Engineering from University of Massachusetts at Amherst in 1993. Between 1994 and 1996, he worked on high performance routers and ATM switches in IBM Networking System Division, Research Triangle Park, North Carolina. Since January 1996, he has been with Computer Science Department, the Hong Kong University of Science and Technology, where he is an associated professor and co-director for the ATM/IP cooperate research center, a government sponsored research center. Since 1999, he has also held an adjunct researcher position at the Microsoft Research Asia (MSRA), Beijing, China. His current research interests include wireless mobile networking supporting multimedia, video multicast and all optical networks using WDM, in which he has published over 150 technical papers in referred journals and conference proceedings. He has been an editor or a guest editor for 16 journals, and involved in the organization of about 40 conferences. He was the Co-TPC Chair for IEEE Infocom'2004. He is a member of ACM and a senior member of IEEE. Krishna M. Sivalingam (ACM ‘93) is an Associate Professor in the Dept. of CSEE at University of Maryland, Baltimore County. Previously, he was with the School of EECS at Washington State University, Pullman from 1997 until 2002; and with the University of North Carolina Greensboro from 1994 until 1997. He has also conducted research at Lucent Technologies' Bell Labs in Murray Hill, NJ, and at AT&T Labs in Whippany, NJ. He received his M.S. and Ph.D. degrees in Computer Science from State University of New York at Buffalo in 1990 and 1994 respectively; and his B.E. degree in Computer Science and Engineering in 1988 from Anna University, Chennai (Madras), India. While at SUNY Buffalo, he was a Presidential Fellow from 1988 to 1991. His research interests include wireless networks, optical wavelength division multiplexed networks, and performance evaluation. He holds three patents in wireless networks and has published several research articles including more than twenty-five journal publications. He has published an edited book on Wireless Sensor Networks in 2004 and on optical networks in 2000 and in 2004. He is a member of the Editorial Board for ACM Wireless Networks Journal, IEEE Transactions on Mobile Computing, and KICS Journal of Computer Networks. He has served as a Guest Co-Editor for special issues of ACM MONET on “Wireless Sensor Networks” in 2003 and 2004 and an issue of IEEE Journal on Selected Areas in Communications on optical WDM networks (2000). He is co-recipient of the Best Paper Award at the IEEE International Conference on Networks 2000 held in Singapore. His work has been supported by several sources including AFOSR, NSF, Cisco, Intel and Laboratory for Telecommunication Sciences. He is a member of the Editorial Board for ACM Wireless Networks Journal, IEEE Transactions on Mobile Computing, and KICS Journal of Computer Networks. He is serving as Technical Program Co-Chair for the First IEEE Conference on Sensor Communications and Networking to be held in Santa Clara, CA in 2004. He has served as General Co-Chair for SPIE Opticomm 2003 (Dallas, TX) and for ACM Intl. Workshop on Wireless Sensor Networks and Applications (WSNA) 2003 held on conjunction with ACM MobiCom 2003 at San Diego, CA. He served as Technical Program Co-Chair of SPIE/IEEE/ACM OptiComm conference at Boston, MA in July 2002; and as Workshop Co-Chair for WSNA 2002 held in conjunction with ACM MobiCom 2002 at Atlanta, GA in Sep 2002. He is a Senior Member of IEEE and a member of ACM. Kazem Sohraby received the BS, MS and PhD degrees in electrical engineering and the MBA from the Wharton School, University of Pennsylvania, Philadephia. He is a Professor of the Electrical Engineering Department, College of Engineering, University of Arkansas, Fayetteville. Prior to that, he was with Bell Laboratories, Holmdel, NJ. His areas of interest include computer networking, signaling, switching, performance analysis, and traffic theory. He has over 20 applications and granted patents on computer protocols, wireless and optical systems, circuit and packet switching, and on optical Internet. He has several publications, including a book on The Performance and Control of Computer Communications Networks (Boston, MA: 1995). Dr Sohraby is a Distinguished Lecturer of the IEEE Communications Society, and serves as its President's representative on the Committee on Communications and Information Policy (CCIP). He served on the Education Committee of the IEEE Communications Society, is on the Editorial Boards of several publications, and served as Reviewer and Panelist with the National Science Foundation, the US Army and the Natural Sciences and Engineering Research Council of Canada. 相似文献
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Many 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. 相似文献
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Reliable Multicast in Multi-Access Wireless LANs 总被引：8，自引：0，他引：8
Multicast is an efficient paradigm for transmitting data from a sender to a group of receivers. In this paper, we focus on multicast in single channel multi-access wireless local area networks (LANs) comprising several small cells. In such a system, a receiver cannot correctly receive a packet if two or more packets are sent to it at the same time, because the packets collide. Therefore, one has to ensure that only one node sends at a time. We look at two important issues. First, we consider the problem of the sender acquiring the multi-access channel for multicast transmission. Second, for reliable multicast in each cell of the wireless LAN, we examine ARQ-based approaches. The second issue is important because the wireless link error rates can be very high.We present a new approach to overcome the problem of feedback collision in single channel multi-access wireless LANs, both for the purpose of acquiring the channel and for reliability. Our approach involves the election of one of the multicast group members (receivers) as a leader or representative for the purpose of sending feedback to the sender. For reliable multicast, on erroneous reception of a packet, the leader does not send an acknowledgment, prompting a retransmission. On erroneous reception of the packet at receivers other than the leader, our protocol allows negative acknowledgments from these receivers to collide with the acknowledgment from the leader, thus destroying the acknowledgment and prompting the sender to retransmit the packet.Using analytical models, we demonstrate that the leader-based protocol exhibits higher throughput in comparison to two other protocols which use traditional delayed feedback-based probabilistic methods. Last, we present a simple scheme for leader election. 相似文献
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In this paper, we propose a modified discrete Hopfield neural networks algorithm for the channel assignment problem. In opposition
to previous work, we tried to apply the optimization locally on a per cell basis in order to reduce the CPU processing time
and decrease the designed system complexity while obtaining a near-optimum solution. In addition, the research is extended
to study the algorithm performance in a more realistic cellular system where the number of requested channels is continuously
changing with time. In this paper, the channel assignment problem is formulated as an energy function which is at its minimum
when all the defined compatibility constraints are satisfied and the assigned channel number (ACN) is equal to the requested
channel number (RCN) in each cell. 相似文献
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无线ad hoc网络中,提高网络容量的一个重要的方法是增加网络的空间复用。增加网络的空间复用主要有两种途径:减小节点的发送功率和增大节点的载波监听阈值。但是减少发送功率和增大载波监听阈值分别使得接收到的信号强度降低和累积干扰水平增高,使得接收节点处的信噪比(SINR)降低,从而导致数据传输率降低影响了网络的空间复用。文章首先建立合理的干扰模型,该模型能够检测到所有的隐藏终端。并结合香农定理,建立了网络空间复用同节点发送功率和载波监听阈值的数学模型。当传输距离为200m,路径衰减指数为3时,发送功率/载波监听阈值=1.7×108,网络的容量达到最大。 相似文献
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为了解决无线Mesh网络中的信道分配问题,提出了一种基于博弈论的信道分配算法.该算法将网络中每一个节点模型化为一个博弈者,每个博弈者的策略为信道的分配方案,并将整个网络的吞吐量作为效用函数的目标,效用函数的物理意义则是在给定流量需求矩阵下传输的成功率.博弈者通过相互博弈来优化收益函数以最大化网络吞吐量.通过NS2.34仿真分析得出,GBCA算法在收敛性、丢包率和吞吐量上都要优于当前的算法. 相似文献
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利用仿真语言对短程脉冲无线信道进行仿真研究。考虑短程脉冲无线传播环境为具有某一密度的随机分布的散射体,在一种理想情况下,信道传播环境表现为一个渗透网格。利用仿真语言仿真短程脉冲无线信道中多径分量的传播轨迹,通过脉冲无线信道的随机模型对短程脉冲无线信道特性进行仿真分析,仿真结果表明：利用该模型对短程脉冲无线信道仿真是有效的。 相似文献
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Network topology construction and its channel assignment for each node in the constructed network topology are two main problems in the initialization of topology building. Topology control is an effective way to solve the problem of topology building. To investigate the joint effect of topology control and channel assignment, we propose a joint processing scheme composed of a k‐Neighbor topology control algorithm and a greedy channel assignment (GCA) algorithm in this paper. Based on this joint processing scheme, the relationships between the energy consumption, the total required channel number and the network connectivity are discussed. We also discuss the impact of some parameters on the performance of networks in terms of the path loss factor, node density, maximum node degree, etc. Our main contributions in this paper is that we find that topology control has a good effect on improving the performance of channel assignment, and the proposed joint processing scheme can reduce the required channel number effectively, compared with its theoretical upper bound. In particular, if the node degree in a network is not more than k, various simulations indicate that the required channel number is not more than 2k + 1. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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In this paper, we consider cluster-based micro/picocellular networks with overlapped cell-clusters. Channel assignment and
hand-off policies are essential and important policies in cellular wireless networks. The issue of how different channel assignment
and hand-off policies in the overlapped areas affect the overall system performance has not yet been studied in the literature.
This paper provides a thorough study and understanding of this issue. We propose two cluster channel assignment policies,
namely, partitioned and shared cluster channel assignment policies, and two hand-off policies, namely, boundary and early
hand-off policies. The proposed cluster channel assignment policies and hand-off policies are combined to obtain three different
strategies, namely, partitioned-boundary, partitioned-early, and shared-boundary strategies. Extensive simulations are used
to study the performance of the strategies. Our results show that the partitioned-early and shared-boundary strategies produce
significantly lower hand-off dropping and forced termination probabilities than the partitioned-boundary strategy. The partitioned-early
and shared-boundary strategies yield similar performance. 相似文献
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多信道技术能够显著提升无线网状网络的容量,合理高效的信道分配方案是多信道网状网络的核心问题。本文提出了一种分布式的信道分配方法CBLA（Cluster-Based Load-Aware）,结合了静态信道分配简单和动态信道分配灵活的特点;借助簇结构降低了问题的规模;根据统计开销小的局部信息监测链路负载;自适应的动态分配有效减轻了链路负载;采用了一种新的结合跳步数、信道分布情况和簇信息的选路指标。实验结果表明CBLA有效降低了数据包的平均延迟,并显著提升了网络吞吐量。 相似文献
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In this work, we develop a prioritized bridging mechanism between the IEEE 802.15.6‐based wireless body area networks (WBANs) and the IEEE 802.11e enhanced distributed channel access (EDCA)‐based wireless local area network (WLAN) to convey the medical data to the medical center. We map the eight WBAN user priorities (UPs) into the four WLAN access categories (ACs) to provide the required quality of service and prioritization for the health variables generated by the WBAN nodes. By assignment of WBAN UPs with default medium access control parameters to eight different medical data streams and under the presence of ordinary nodes, we investigate the impact of WLAN AC differentiation by arbitrary inter‐frame space (AIFS) and contention window (CW) on performance of medical and regular nodes’ data streams. The results of this work indicate that the AC differentiation by AIFS outperforms the differentiation by CW in the sense that it does not deteriorate the end‐to‐end delay of relayed WBAN traffic and ordinary WLAN traffic.Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Bahador Bakhshi Siavash Khorsandi 《International Journal of Communication Systems》2013,26(3):293-314
Channel assignment in multichannel multiradio wireless mesh networks is a powerful resource management tool to exploit available multiple channels. Channels can be allocated either statically on the basis of long‐term steady state behavior of traffic or dynamically according to actual traffic demands. It is a common belief that dynamic schemes provide better performance; however, these two broad classes of channel allocation schemes have not been compared in detail. In this paper, we quantify the achievable performance gain and fairness improvement through an optimal dynamic channel allocation scheme. We develop optimal algorithms for a dynamic and three static schemes using mixed integer linear programming and compare them in the context of QoS provisioning, where network performance is measured in terms of acceptance rate of QoS sensitive traffic demands. Our extensive simulations show that static schemes should optimize channel allocation for long‐term traffic pattern and maintain max–min fairness to achieve acceptable performances. Although the dynamic and max–min fair static schemes accomplish the same fairness, the dynamic channel allocation outperforms the static scheme about 10% in most cases. In heavily overloaded regimes, especially when network resources are scarce, both have comparable performances, and the max–min fair scheme is preferred because it incurs less overhead. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Yixin Jiang Chuang Lin Hao Yin Zhen Chen 《Wireless Communications and Mobile Computing》2008,8(1):101-112
IEEE 802.11 wireless local area networks (WLAN) has been increasingly deployed in various locations because of the convenience of wireless communication and decreasing costs of the underlying technology. However, the existing security mechanisms in wireless communication are vulnerable to be attacked and seriously threat the data authentication and confidentiality. In this paper, we mainly focus on two issues. First, the vulnerabilities of security protocols specified in IEEE 802.11 and 802.1X standards are analyzed in detail. Second, a new mutual authentication and privacy scheme for WLAN is proposed to address these security issues. The proposed scheme improves the security mechanisms of IEEE 802.11 and 802.1X by providing a mandatory mutual authentication mechanism between mobile station and access point (AP) based on public key infrastructure (PKI), offering data integrity check and improving data confidentiality with symmetric cipher block chain (CBC) encryption. In addition, this scheme also provides some other new security mechanisms, such as dynamic session key negotiation and multicast key notification. Hence, with these new security mechanisms, it should be much more secure than the original security scheme. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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In order to realize the reduction of equipment cost and the demand of higher capacity,wireless mesh network(WMN) router devices usually have several interfaces and work on multi-channels.Jointing channel allocation,interface assignment and routing can efficiently improve the network capacity.This paper presents an efficient channel assignment scheme combined with the multi-radio link quality source routing(MR-LQSR) protocol,which is called channel assignment with MR-LQSR(CA-LQSR).In this scheme,a physical interference model is established:calculated transmission time(CTT) is proposed as the metric of channel assignment,which can reflect the real network environment and channel interference best,and enhanced weighted cumulative expected transmission time(EWCETT) is proposed as the routing metric,which preserves load balancing and bandwidth of links.Meantime,the expression of EWCETT contains the value of CTT,thus the total cost time of channel assignment and routing can be reduced.Simulation results show that our method has advantage of higher throughput,lower end-to-end time delay,and less network cost over some other existing methods. 相似文献
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随着移动业务的日益发展,网络的规模越来越大,无线接入性这一指标,已成为网络安全、高效运行的重要衡量标准,也是客户感知的重要体现,中国移动集团公司和省公司都十分重视,明确要求各地市公司以提升无线接入性为重要考核手段。湖州移动为了提高无线接入性,通过对影响无线接入性的原因进行逐一的跟踪分析,从业务信道分配成功率和信令信道分配成功率两个角度出发,深入分析半速率启动机制、双频网建设、位置区划分、信令信道资源情况和相关参数调整,得出了一套提升无线接入性指标的优化思路。通过实践证明,该优化方法是切实可行的。 相似文献