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121.
有线数字电视整转过渡期间,模拟、数字电视信号同缆传输将会存在一段时间,如何尽量减少模拟、数字两种电视信号的相互干扰是至关重要的问题,这里包括对机房前端的信号调制、网络传输的技术指标分配、终端接收的信号调节等环节,必须严格执行有关的技术规范。 相似文献
122.
在多用户正交频分复用(MU-OFDM)系统中,考虑各个用户之间具有比例数据传输速率限制条件下的一种公平的自适应资源分配方案的最优算法计算量巨大,为此,提出了一种将子信道分配和功率分配相分离的次优算法.首先,在假设相同功率分配的情况下进行子信道的分配,然后在保持一定比例公平条件下使总容量最大时进行最优功率分配.对该算法的仿真表明,在用户数为2、子信道数为10的系统中,所提算法的容量性能接近最优算法,而计算量由指数增长变为线性增长.所提资源分配算法的总容量比以前的算法在用户间的分配更公平也更灵活. 相似文献
123.
多服务多用户OFDM系统资源分配算法 总被引:1,自引:1,他引:0
提出了一种正交频分复用(OFDM)系统的多服务多用户资源分配算法。与传统多用户OFDM系统资源分配算法只考虑一种类型的服务不同,提出的算法同时考虑了数据业务和语音业务,分析了两种业务不同的资源分配需求,对语音业务采用了时分多址(TDMA)的方式,并且加入了对每种数据业务最低传输速率的要求。仿真结果表明,新算法能够在满足语音用户固定传输容量的基础上,提升数据用户总的传输容量,同时保证每一个数据用户的最低传输容量的要求。 相似文献
124.
Cooperative diversity is a new technology to improve bit error rate(BER)performance in wireless communications.A new power allocation algorithm to improve BER performance in cellular uplink has been proposed in this paper.Some existing power allocation schemes were proposed for the purpose of maximizing the channel capacity or minimizing the outage probability.Different from these schemes,the proposed algorithm aims at minimizing the BER of the systems under the constraint of total transmission power.Besides this characteristic,the proposed algorithm can realize a low complexity real-time power allocation according to the fluctuation of channels.Simulation results show that the proposed algorithm can decrease the BER performance of the systems effectively. 相似文献
125.
Pervasive computing,which requires applications composed of independent and distributed components,is an important domain for dynamic ubiquitous heterogeneous environment.However,one of the critical challenges it faces is resource allocation.To overcome the difficulty,enhanced universal service terminal(UST+) is designed as a reflective middleware combined distributed components with particular features to achieve user goals.Moreover,a novel algorithm based on microeconomics is presented to resolve conflict... 相似文献
126.
In adaptive channel allocation for secondary user(SU) of cognitive radio(CR) system,it is necessary to consider allocation process from the temporal perspective.In this article,a chain store game is modeled to achieve SU's equilibrium state.Due to the computational complexity of solving equilibrium states,the authors explore the correlated equilibrium(CE) by importing signal mechanisms based on time and sequence number.Also,correlated equilibrium based game algorithms are presented.Simulations show that the... 相似文献
127.
Development of fair and efficient bandwidth allocation and admission control schemes is one of the key issues in the design of IEEE 802.16 broadband wireless access systems in time division multiple access (TDMA) mode. In this article, the problem of bandwidth allocation and admission control is formulated as a Nash bargaining model. The nash bargaining solution (NBS) derived from the cooperative game is adopted to maximize the spectrum utilization. Analysis and simulation results show that there is a unique Pareto optimal bandwidth allocation solution by using NBS among various flows. Furthermore, maximum utility of the system can also be maintained by using the admission control policy with different number of connections and variable channel qualities. The total throughput of the proposed scheme is close to the maximal one, while significantly improving fairness compared to the existing solutions. 相似文献
128.
HAO Zhi-jie XU Xiao-dong ZHAO Ying-hong TAO Xiao-feng LI Lin-jun ZHANG Zhong-qi 《中国邮电高校学报(英文版)》2010,17(2):14-18,45
Utility based resource allocation strategy in multi-cell orthogonal frequency-division multiplexing (OFDM) system plays a critical role in next generation mobile communication systems. Based on the analysis of risk aversion utility functions, this article proposed the system utility based utility, which is named the customer satisfaction (CS) utility. Compared with the proportional fairness (PF) utility, the CS utility reflects the user demands better, and enables the system to adjust its resource allocation according to both the traffic requirements and the resource situation. 相似文献
129.
Zhao Chenglin Xu Fangmin Sun Xuebin Sun Songlin Jiang Ting Key Laboratory of Universal Wireless Communication Ministry of Education Wireless Network Lab Beijing University of Posts Telecommunications Beijing P. R. China Samsung China Communication R&D Center Beijing P. R. China 《中国通信》2010,7(2):109-116
The integration of cognitive radio and Ultra wideband (UWB) networks has attracted lots of research interests. Cognitive UWB networks not only provide very high data rates but also guarantee the uninterrupted communication of primary system operated in the same frequency band. In this work, the problem of the capacity analyses of cognitive UWB networks is investigated. Different from the conventional cognitive spectrum sharing model which can only utilize the idle spectrum hole, the cognitive UWB system can... 相似文献
130.
The IEEE 802.22 standard based on wireless Cognitive Radio (CR) is an optimal solution to resolve the inefficient spectrum
utility problem. In this paper, we focus on the spectrum allocation in IEEE 802.22 mesh networks and propose a new graph-theory
algorithm. The algorithm aims at two objectives: one is the sum of the allocated channel bandwidth is maximum, and the other
is the number of users can be active simultaneity is maximum. In this proposed algorithm, the topology of network was modeled
as a general graph and could be transformed into a weighted complete bipartite-graph by three processes. The simulations show
that the presented algorithm can improve the performance of spectrum allocation. 相似文献