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941.
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Hongfei Du Linghang Fan Barry G. Evans 《International Journal of Satellite Communications and Networking》2009,27(1):53-85
With their inherent broadcast capabilities and reliable extensive geographical coverage, the broadband satellite networks are emerging as a promising approach for the delivery of multimedia services in 3G and beyond systems. Given the limited capacity of the satellite component, to meet the diverse quality of service (QoS) demands of multimedia applications, it is highly desired that the available resources can be adaptively utilized in an optimized way. In this paper, we draw our attention on the development and evaluation of an efficient packet scheduling scheme in a representative broadband satellite system, namely satellite digital multimedia broadcasting (SDMB), which is positioned as one of the most attractive solutions in the convergence of a closer integration with the terrestrial mobile networks for a cost‐effective delivery of point‐to‐multipoint services. By taking into account essential aspects of a successful QoS provisioning while preserving the system power/resource constraints, the proposed adaptive multidimensional QoS‐based (AMQ) packet scheduling scheme in this paper aims to effectively satisfy diverse QoS requirements and adaptively optimize the resource utilization for the satellite multimedia broadcasting. The proposed scheme is formulated via an adaptive service prioritization algorithm and an adaptive resource allocation algorithm. By taking into account essential performance criteria, the former is capable of prioritizing contending flows based on the QoS preferences and performance dynamics, while the latter allocates the resources, in an adaptive manner, according to the current QoS satisfaction degree of each session. Simulation results show that the AMQ scheme achieves significantly better performance than those of existing schemes on multiple performance metrics, e.g. delay, throughput, channel utilization and fairness. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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According to the property rights model of cognitive radio,primary users who own the spectral resource have the right to lease or trade part of it to secondary users in exchange for appropriate profit. In this paper,an implementation of this framework is investigated,where a primary link can lease the owned spectrum to secondary nodes in exchange for cooperation (relaying). A novel pricing model is proposed that enables the trading between spectrum and cooperation. Based on the demand of secondary nodes,the primary link attempts to maximize its quality of service (QoS) by setting the price of spectrum. Taking the price asked by primary link,the secondary nodes aim to obtain most profits by deciding the amount of spectrum to buy and then pay for it by cooperative transmission. The investigated model is conveniently cast in the framework of seller/buyer (Stackelberg) games. Analysis and numerical results show that our pricing model is effective and practical for spectrum leasing based on trading spectral resource for cooperation. 相似文献
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In this article, a new effective method of cooperative modulation recognition (CMR) is proposed to recognize different modulation types of primary user for cognitive radio receivers. In the cognitive radio (CR) system, two CR users respectively send their feature parameters to the cooperative recognition center, which is composed of back propagation neural network (BPNN). With two users' cooperation and the application of an error back propagation learning algorithm with momentum, the center improves the performance of modulation recognition, especially when one of the CR users' signal-to-noise ratio (SNR) is low. To measure the performance of the proposed method, simulations are carried out to classify different types of modulated signals corrupted by additive white Gaussian noise (AWGN). The simulation results show that this cooperation algorithm has a better recognition performance than those without cooperation. 相似文献
948.
一种宽带中频数字化处理平台 总被引:2,自引:2,他引:0
为解决软件无线电领域无法实时处理宽带中频信号的问题,研究了软件无线电中频数字化处理技术的基础理论和关键技术。设计实现了基于CPCI架构的中频数字化处理平台,介绍该平台的设计原理,并给出平台所用器件的原理框图。借助摩托罗拉超短波电台调制信号,通过该平台上实现的数字下变频和基于正交解调的FM算法对该信号的成功处理,验证了该设计平台能够实时处理宽带中频信号。 相似文献
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