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1.
无线网状网中基于干扰模型的多信道分配策略   总被引:5,自引:3,他引:5       下载免费PDF全文
束永安  洪佩琳  覃振权 《电子学报》2008,36(7):1256-1260
为解决信道干扰导致无线网状网吞吐量下降的问题,本文提出一种新的基于干扰模型的多信道分配策略.首先对网络进行分层,然后按照优先级逐层进行信道分配,通过降低信道间的干扰来提高每个结点的吞吐量,进而提高整个网络的吞吐量.仿真结果表明了该策略的有效性.  相似文献   

2.
In this paper we apply the concept of overlay cognitive radio to the communication between nodes in a wireless mesh network. Based on the overlay cognitive radio model, it is possible to have two concurrent transmissions in a given interference region, where usually only one communication takes place at a given time. We analyze the cases of wireless mesh networks with regular and random topologies. Numerical results show that considerable network capacity gains can be achieved.  相似文献   

3.
Multi-radio channel allocation (MRCA) is a key issue to improve the system performance supporting all kinds of mobile applications in wireless networks. However, existed work on non-cooperative MRCA just considers the cases under the extreme saturation load condition and static game, which means that it is assumed that all the nodes always have packets to send and mobile terminals just change the channel once. Such assumption is obviously impractical for actual wireless network and isn’t suitable for the mobility of applications without intelligent spectrum management. Meanwhile, the existed schemes are unable to support mobile applications with time-varying channel. In this paper, an enforceable incentive mechanism called EIM is proposed for dynamic non-cooperative multi-radio channel allocation to support mobile applications. In order to optimize the overall performance of mobility management, in the proposed EIM, the strong assumption of saturation network traffic is relaxed, which makes the mobile terminals are able to have time-varying bandwidth requirements. Then, the MRCA problem is modeled as an infinite repeated game. Detailed theoretical analysis proves that there exist multiple pure Nash Equilibriums (NEs) for the game, and, under certain condition, there also exist NEs which are not Pareto-Optimal. Hence, based on the punishment strategy, the proposed EIM can achieve social welfare. Detailed numerical and simulation results show that the proposed EIM can improve the system throughput about 15 % compared with the existed works, which can provide an efficient method to manage channel resource and get better ubiquitous online access to preferred mobile services.  相似文献   

4.
宽带无线接入网得到广泛应用,廉价的数据回程带宽是决定宽带无线接入网成功应用的重要因素。丈中设计了一种使用多射频、多信道、方向性天线的新型无线mesh数据回程网,提出了一种基于连接图的等价变换来实现该无线mesh网络信道分配算法。仿真结果表明,文中提出的信道分配算法有效地减少链路间干扰,提高了网络性能。  相似文献   

5.
Cross-Layer Fair Bandwidth Sharing for Multi-Channel Wireless Mesh Networks   总被引:1,自引:0,他引:1  
In a wireless mesh network (WMN) with a number of stationary wireless routers, the aggregate capacity can be increased when each router is equipped with multiple network interface cards (NICs) and each NIC is assigned to a distinct orthogonal frequency channel. In this paper, given the logical topology of the network, we mathematically formulate a crosslayer fair bandwidth sharing problem as a non-linear mixedinteger network utility maximization problem. An optimal joint design, based on exact binary linearization techniques, is proposed which leads to a global maximum. A near-optimal joint design, based on approximate dual decomposition techniques, is also proposed which is practical for deployment. Performance is assessed through several numerical examples in terms of network utility, aggregate network throughput, and fairness index. Results show that our proposed designs can lead to multi-channelWMNs which are more efficient and fair compared to their singlechannel counterparts. The performance gain on both efficiency and fairness increase as the number of available NICs per router or the number of available frequency channels increases.  相似文献   

6.
Future mobile communication systems will be designed to support a wide range of data rates with complex quality of service matrix. It is becoming more challenging to optimize the radio resource management and maximise the system capacity whilst meeting the required quality of service from user?s point of view. Traditional schemes have approached this problem mainly focusing on resources within a cell and to large extent ignoring effects of multi-cell architecture. This paper addresses the influence of multi-cell interference on overall radio resource utilisation and proposes a novel approach, setting a new direction for future research on resource scheduling strategies in a multicell system. It proposes a concept called Load Matrix (LM) which facilitates joint management of interference within and between cells for allocation of radio resources. Simulation results show significant improvement in the resource utilization and o verall network performance. Using the LM strategy, average cell throughput can be increased as much as 30% compared to a benchmark algorithm. Results also show that maintaining cell interference within a margin instead of a hard target can significantly improve resource utilization.  相似文献   

7.
无线网状网(Wireless Mesh Network,WMN)是一种新型的分布式宽带无线网络结构.典型的移动Ad Hoc网络具有节点移动性小、受电池动力限制和用户带宽需求大等特点,从而导致传统单信道的Ad Hoc结构不再满足WMN用户的需求.为了提供更大的带宽,多信道技术得到越来越多应用.探讨了WMN的网络结构与特点,对现有几种典型的多信道技术进行了比较,提出了一种基于单射频的无线Mesh网多信道的设计方案,不同网关节点所代理的节点使用不同的信道进行通信,从而避免了不同子网节点之间的信道干扰.通过NS2的仿真与分析表明,该方法在特定环境下的网络性能是传统单射频单信道方法的2倍.  相似文献   

8.
This paper investigates the interaction between end-to-end flow control and medium access control (MAC)-layer scheduling on wireless links. We consider a wireless network with multiple users receiving information from a common access point; each user suffers fading and a scheduler allocates the channel based on channel quality but is subject to fairness and latency considerations. We show that the fairness property of the scheduler is compromised by the transport-layer flow control of transmission control protocol (TCP) New Reno. We provide a receiver-side control algorithm, CLAMP, that remedies this situation. CLAMP works at a receiver to control a TCP sender by setting the TCP receiver's advertised window limit, and this allows the scheduler to allocate bandwidth fairly between the users.  相似文献   

9.
Cognitive radio has been recently considered as a flexible spectrum usage model to improve the spectrum efficiency. In this paper, we develop a new power allocation approach by geometric programming (GP) to realize the coexistence of a primary user (PU) and multiple cognitive users (CUs) in the same frequency band. The objective is to minimize the total power consumption of CUs while guaranteeing the not only protection of PU but also the quality of service (QoS) of multiple CUs, which is different from previous works. In order to facilitate the centralized computation, a distributed algorithm is developed to adaptively adjust the transmit power of each CU. Numerical results are provided to show the effectiveness of the proposed algorithm in power saving.  相似文献   

10.
无线mesh网络是下一代无线网络技术中人们研究与关注的热点技术之一。根据最新IEEE 802.11s协议,其路由判据是基于无线感知的空时链路判据(airtime link metric,ALM)。这种路由判据比传统的以跳数作为判据要好,但是当多信道或多射频条件下时,这种判据会引起信道容量的衰减,不足以满足如今的网络需求。因此,有许多新的路由判据被提出。例如,加权累计期望传输时间,干扰及信道切换,归一化的瓶颈链路容量等。本文主要定性的比较这些判据的特点,然后通过NS-2进行网络仿真,根据IEEE 802.11s协议中默认的路由协议,将这些多信道条件下的路由判据进行相互比较。由此,得出结论,明确各种路由判据所适用的不同的场合。  相似文献   

11.
Wireless mesh networking is an emerging technology for future broadband wireless access. Future wireless networking can benefit from a robust and reliable wireless mesh backbone rendered by mesh routers, providing an all-wireless ambience. Due to the requisite multichannel communications for high-speed data transmissions, power allocation for opportunistically exploiting fading wireless channels, and packet scheduling for QoS provisioning, joint power-frequency-time resource allocation is indispensable. In this article we propose a low-complexity intracluster resource allocation algorithm, taking power allocation, subcarrier allocation, and packet scheduling into consideration. Numerical results demonstrate that our scheme is near optimal, and that our optimality-driven resource allocation approach outperforms a greedy algorithm, working out a better performance compromise among throughput, packet dropping rate, and packet delay.  相似文献   

12.
On Path Selection and Rate Allocation for Video in Wireless Mesh Networks   总被引:4,自引:0,他引:4  
Multi-path transport is an important mechanism for supporting video communications in multihop wireless networks. In this paper, we investigate the joint problem of optimal path selection and rate allocation for multiple video sessions in a wireless mesh network. We present a mathematical formulation to optimize the application level performance (i.e., video distortion) in the context of path selection and rate allocation. For this complex optimization problem, we propose a branch-and-bound based solution procedure, embedded with the Reformulation-Linearization Technique (RLT) that can produce $(1-epsilon)$-optimal solutions for any small $epsilon$ . This result is significant as it not only provides theoretical understanding of this problem, but also offers a performance benchmark for any future proposed distributed algorithm and protocol for this problem. Simulation results are also provided to demonstrate the efficacy of the solution procedure.   相似文献   

13.
Fair Allocation of Subcarrier and Power in an OFDMA Wireless Mesh Network   总被引:2,自引:0,他引:2  
This paper presents a new fair scheduling scheme for orthogonal frequency-division multiple-access-based wireless mesh networks (WMNs), which fairly allocates subcarriers and power to mesh routers (MRs) and mesh clients to maximize the Nash bargaining solution fairness criterion. In WMNs, since not all the information necessary for scheduling is available at a central scheduler (e.g., MR), it is advantageous to involve the MR and as many mesh clients as possible in distributed scheduling based on the limited information that is available locally at each node. Instead of solving a single global control problem, we hierarchically decouple the subcarrier and power allocation problem into two subproblems, where the MR allocates groups of subcarriers to the mesh clients, and each mesh client allocates transmit power among its subcarriers to each of its outgoing links. We formulate the two subproblems by nonlinear integer programming and nonlinear mixed integer programming, respectively. A simple and efficient solution algorithm is developed for the MR's problem. Also, a closed-form solution is obtained by transforming the mesh client's problem into a time-division scheduling problem. Extensive simulation results demonstrate that the proposed scheme provides fair opportunities to the respective users (mesh clients) and a comparable overall end-to-end rate when the number of mesh clients increases  相似文献   

14.
Enabling Efficient Peer-to-Peer Resource Sharing in Wireless Mesh Networks   总被引:1,自引:0,他引:1  
Wireless mesh networks are a promising area for the deployment of new wireless communication and networking technologies. In this paper, we address the problem of enabling effective peer-to-peer resource sharing in this type of networks. Starting from the well-known Chord protocol for resource sharing in wired networks, we propose a specialization that accounts for peculiar features of wireless mesh networks: namely, the availability of a wireless infrastructure, and the 1-hop broadcast nature of wireless communication, which bring to the notions of location awareness and MAC layer cross-layering. Through extensive packet-level simulations, we investigate the separate effects of location awareness and MAC layer cross-layering, and of their combination, on the performance of the P2P application. The combined protocol, MeshChord, reduces message overhead of as much as 40 percent with respect to the basic Chord design, while at the same time improving the information retrieval performance. Notably, differently from the basic Chord design, our proposed MeshChord specialization displays information retrieval performance resilient to the presence of both CBR and TCP background traffic. Overall, the results of our study suggest that MeshChord can be successfully utilized for implementing file/resource sharing applications in wireless mesh networks.  相似文献   

15.
16.
This paper focuses on resource allocation problem of limited feedback in OFDM-based clustered wireless mesh networks. Firstly, the channel quantization codebook is designed according to the equal probability quantizer and joint power, rate and channel quantization threshold codebook scheme (PRCQT) is proposed. Secondly, we deduce the subcarrier allocation criterion utilizing the Lagrange multiplier method. Finally, stochastic resource allocation scheme of limited feedback (SRALF) utilizing the stochastic optimization tools for OFDM-based clustered WMNs is proposed. Simulation results demonstrate SRALF+PRCQT scheme not only improves the network throughput, but also has advantage of limited feedback overhead.  相似文献   

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18.
针对能量受限的合作认知网络,该文研究在保证主用户服务质量要求下,认知用户能量效率最大化问题。认知用户利用信能同传技术接收主用户信号,并采用解码转发协议协助主用户通信。基于分式规划和引入辅助变量将原始非凸问题转换为凸优化问题进行求解,并提出一种迭代的资源分配算法。仿真结果表明,所提算法能够快速收敛于最优解。与能量合作方案相比,该文所采用方案能量效率显著提高,同时能更好地保证主用户服务质量要求。  相似文献   

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20.
Two Inter-cell Interference (ICI) management algorithms: Primary Interference Balancing (PIB) algorithm and Interfering Bits Loading Avoidance (IBLA) algorithm are proposed for canceling the ICI effects which the existing efficient radio resource allocation algorithms do not consider. The efficient radio resource allocation algorithm, i.e., Pre-assignment and Reassignment (PR) algorithm, obtains the lowest complexity and achieves good throughput performance in single cell OFDMA system. However, in multi-cel...  相似文献   

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