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1.
Video streaming is one of the most important applications that will make use of the high data rates offered by 4G networks. The current video transport techniques are already very advanced, and the more immediate problems lie in the joint optimization of video coding, AL-FEC, and PHY rate selection with the goal of enhancing the user perceived quality. In this work we provide an analysis of video broadcast streaming services for different combinations of layered coding and AL-FEC, using a realistic LTE PHY layer. Our simulation results show that the scalable content adaptation given by Scalable Video Coding (SVC) and the scheduling flexibility offered by the 3G-LTE MAC-layer provide a good match for enhanced video broadcast services for next generation cellular networks. Our proposed solution is compared to baseline algorithms and broadcast systems based on H.264/AVC streaming solutions. We emphasize the system quality improvement brought by our solution and discuss implications for a wide-scale practical deployment.  相似文献   

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In wireless networks, multi-user video streaming under limited resource is a challenging problem. The main challenge is how to meet the transmission requirements under the different channel condition and video content complexity. In this paper, we propose an uncoded video transmission framework to deliver the multi-user video over wireless networks. In order to evaluate the overall performance of multi-user network more practically, three optimization strategies are proposed in this paper: 1) minimizing the total distortion; 2) minimizing the maximal distortion; 3) minimizing the summation of square root distortion. Furthermore, the corresponding joint resource allocation algorithms are developed to solve the optimization problems. The simulation results demonstrate that different optimization strategies have different resource allocation and performance for each user. The optimization strategy 1) performs the best in terms of average PSNR of all users, the optimization strategy 2) achieves more fair result, and the optimization strategy 3) achieves a good balance. The strategy 3) can improve the performance for users with bad channel condition, while little loss is caused for users with good channel condition.  相似文献   

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Recently, the notion that a logical next step towards future mobile radio networks is to introduce multihop relaying into cellular networks, has gained wide acceptance. Nevertheless, due to the inherent drawbacks of multihop relaying, e.g., the requirement for extra radio resources for relaying hops, and the sensitivity to the quality of relaying routes, multihop cellular networks (MCNs) require a well-designed radio resource allocation strategy in order to secure performance gains. In this paper, the optimal radio resource allocation problem in MCNs, with the objective of throughput maximization, is formulated mathematically and proven to be NP-hard. Considering the prohibitive complexity of finding the optimal solution for such an NP-hard problem, we propose an efficient heuristic algorithm, named integrated radio resource allocation (IRRA), to find suboptimal solutions. The IRRA is featured as a low-complexity algorithm that involves not only base station (BS) resource scheduling, but also routing and relay station (RS) load balancing. Specifically, a load-based scheme is developed for routing. A mode-aware BS resource-scheduling scheme is proposed for handling links in different transmission modes, i.e., direct or multihop. Moreover, a priority-based RS load balancing approach is presented for the prevention of the overloading of RSs. Within the framework of the IRRA, the above three functions operate periodically with coordinated interactions. To prove the effectiveness of the proposed IRRA algorithm, a case study was carried out based on enhanced uplink UMTS terrestrial radio access/frequency-division duplex with fixed RSs. The IRRA is evaluated through system level simulations, and compared with two other cases: 1) nonrelaying and 2) relaying with a benchmark approach. The results show that the proposed algorithm can ensure significant gains in terms of cell throughput  相似文献   

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A cross-layer packet scheduling scheme that streams pre-encoded video over wireless downlink packet access networks to multiple users is presented. The scheme can be used with the emerging wireless standards such as HSDPA and IEEE 802.16. A gradient based scheduling scheme is used in which user data rates are dynamically adjusted based on channel quality as well as the gradients of a utility function. The user utilities are designed as a function of the distortion of the received video. This enables distortion-aware packet scheduling both within and across multiple users. The utility takes into account decoder error concealment, an important component in deciding the received quality of the video. We consider both simple and complex error concealment techniques. Simulation results show that the gradient based scheduling framework combined with the content-aware utility functions provides a viable method for downlink packet scheduling as it can significantly outperform current content-independent techniques. Further tests determine the sensitivity of the system to the initial video encoding schemes, as well as to non-real-time packet ordering techniques.  相似文献   

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Nowadays, the pervasive wireless networks enable ubiquitous high-rate wireless access from everywhere. In this work, we discuss the integration of complementary wireless techniques to construct a personal moving network. The personal wireless devices (  smartphones, camcorders, and netbooks) and even medical monitoring sensors are interconnected with a wide-area backbone through a local multi-mode gateway. The mobile nodes in a personal moving network move in group and are provided seamless connectivity through a backhaul relay channel from the local gateway toward the backbone network. In some specific scenarios, the local gateway can be as simple as a multi-radio smartphone. In this study, we investigate the construction and resource allocation for a personal moving network. Aggregate multi-service traffic of interactive data, conversational video, and electrocardiography (ECG) monitoring are considered in the resource allocation. We develop a stochastic Petri net to model the access selection scheme, which is logically clear and easy to follow. The flow-level performance is evaluated in terms of new connection blocking probability and handoff dropping probability. We further analyze the packet-level performance of the heterogeneous two-hop network. Considering the urgency of medical services, a non-preemptive priority policy is applied to mitigate the impact of background traffic and prioritize the transmission of ECG data.  相似文献   

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Wireless Personal Communications - The issues of content placement and content replication for video-on-demand streaming over cellular networks are addressed in this study. Using many replications...  相似文献   

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面向CDMA蜂窝网的无线定位技术   总被引:1,自引:1,他引:1  
田孝华  廖桂生  赵修斌  王晓薇 《电子学报》2005,33(12):2196-2203
蜂窝通信系统中移动台定位问题作为研究的热点之一,受到了广泛的关注.实现蜂窝通信系统中移动台定位,需要解决定位算法与定位参数估计问题.本文以定位算法与定位参数估计为主线,综述了蜂窝通信系统中移动台定位的发展过程、现状、取得的进展以及面临的挑战,特别是对减轻非视距传播影响的定位算法进行了详细讨论.  相似文献   

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In this study, a channel selection algorithm is proposed to enhance the transmission rate for scalable video coding (SVC) source transmission over multi-input multi-output (MIMO) wireless systems. The proposed algorithm allows each layer of SVC video to choose its appropriate channel in wireless MIMO systems based on channel state information for transmission rate enhancement. Here, this difficult problem is converted into mathematical optimization problem to improve the performance of SVC video transmission. Experimental results show that the transmission rate of the proposed method outperforms the existing scheme.  相似文献   

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Energy-Efficient Resource Allocation in Wireless Networks   总被引:1,自引:0,他引:1  
This paper shows that game theory can be used as a unifying framework to study radio resource management in a variety of wireless networks. with different service criteria. It focuses on infrastructure networks where users transmit to a common concentration point such as a base station in a cellular network or an access point. Since most of the terminals in a wireless network are battery-powered, energy efficiency is crucial to prolonging the life of the terminals. Also, in most practical scenarios, distributed algorithms are preferred over centralized ones. Throughout this article it focuses on distributed algorithms with emphasis on energy efficiency. A family of power control games is presented for energy-efficient resource allocation in wireless code-division multiple-access (CDMA) networks and give discussions and conclusions  相似文献   

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Utility-Based Resource Allocation in Wireless Networks   总被引:1,自引:0,他引:1  
In this paper, we study utility-based maximization for resource allocation in the downlink direction of centralized wireless networks. We consider two types of traffic, i.e., best effort and hard QoS, and develop some essential theorems for optimal wireless resource allocation. We then propose three allocation schemes. The performance of the proposed schemes is evaluated via simulations. The results show that optimal wireless resource allocation is dependent on traffic types, total available resource, and channel quality, rather than solely dependent on the channel quality or traffic types as assumed in most existing work.  相似文献   

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A scalable framework for handling delay-sensitive, real-time mobile group applications over cellular infrastructure is introduced in this work. Examples for such applications are mobile instant messaging services, mobile social networks, mobile conference calls, and mobile multi-player on-line games. The key idea is to exploit the cellular database hierarchy in order to provide group applications in an efficient manner, to scalable groups, starting from 3 to 5 members, up to a few thousands members, dispersed over a wide geographic area. The main focus is on tracking the presence and the locations of the participating members in an efficient manner, and on advanced group services, such as multicast messages and conference calls, to group members, and advanced searches such as “find the nearest taxi”. As a result, the delay associated with delivering a message to many independent users is significantly reduced, in comparison with the delay typically expected from existing cellular networks. The proposed method is consistent with the existing mobility management scheme currently used in cellular networks, and fits into MIP and MIPv6. Thus, it can be easily applied on existing cellular networks, as well as on future all-IP wireless networks.  相似文献   

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针对能效提升、宏用户干扰减小的问题,该文研究了基于干扰效率最大的异构无线网络顽健资源分配算法.首先,考虑宏用户干扰约束、微蜂窝用户速率需求约束和最大发射功率约束,将资源优化问题建模为多变量非线性规划问题.其次,考虑有界信道不确定性模型,利用Dinkelbach辅助变量方法和连续凸近似方法结合对数变换方法,将原分式规划顽健资源分配问题转换为等价的确定性凸优化问题,并利用拉格朗日对偶算法获得解析解.理论分析了计算复杂度和参数不确定性对性能的影响.仿真结果表明该算法具有较好的干扰效率和鲁棒性.  相似文献   

16.
We consider the problem of resource allocation for data transfer between the base station and the users within a cell of a wireless telecommunication network with infinite data queues for each user. The aim is to study the tradeoff between the conflicting objectives of maximizing the system throughput and the quality of service (QoS) to an individual user. Using a policy improvement approach based on Markov decision processes, we develop an intuitive and easy-to-implement index policy. We also demonstrate its superior performance over the existing proportional fair metric algorithm through simulation experiments.  相似文献   

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本文对CDMA蜂窝网络中的无线资源管理研究作综述。内容包括功率控制、接纳控制、越区切换和无线分调度等方面,并考虑了多种业务下的服务质量。  相似文献   

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The Multicarrier CDMA Transmission Techniques for Integrated Broadband Cellular Systems (MATRICE) project addresses a candidate solution for a Beyond 3G (B3G) air-interface based on Multi-Carrier Code Division Multiple Access (MC-CDMA). It investigates dynamic resource allocation strategies at the Medium Access Control (MAC) layer to support the transport of Internet Protocol (IP) packets over the air-interface in a cost effective manner and maximise the cell capacity with a target QoS. A candidate Dynamic Resource Allocation (DRA) protocol architecture is proposed that is based on cross-layer signalling to provide reactive resource allocation according to the fast channel and traffic variations. In-line with B3G expectations, the proposed DRA handles a very large number of users with inherent flexibility and granularity necessary to support heterogeneous traffic, and still with limited complexity. Thanks to the modular architecture of the DRA, various scheduling policies are investigated and compared in terms of capacity and reactivity to the system environment. Simulation results have shown that the MATRICE system has the potential to deliver broadband heterogenous services in a cost-effective manner, and emerge as a propespective candidate air-interface for B3G cellular networks.  相似文献   

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Clustering is an effective way to increase network lifetime but it leads to formation of isolated nodes in the wireless sensor network. These isolated sensor nodes forward data directly to sink and consume more energy which significantly reduces the network lifetime. In this article, we present how to maximize the network lifetime through joint routing and resource allocation with isolated nodes technique (JR-IN) between cluster head and isolated nodes in a cognitive based wireless sensor networks. In JR-IN technique the network area is divided into different layers and cluster size is formulated in each layer such that the size of the cluster remains unequal when it moves towards sink. Hence the cluster size is lager in the outermost layer compared to the cluster size in the inner most layer. To avoid inter cluster collision, we proposed different fixed channel to all the cluster heads in the network. For the intra cluster communication, the cluster member (sensor nodes) will lease the spectrum from the cluster head and forward data to their respective cluster head using TDMA technique. The periodical data gathering of cluster heads and forwarding the data to one hop cluster head may tend to lose energy faster and dies out quickly. We also propose in the JR-IN technique, the isolated nodes in the layer will take charge as a cluster head node and utilizes the resource allocated to the respective cluster head and forward the data to next hop cluster head. Simulation result shows that JR-IN outperforms the existing techniques, maximizes network lifetime and throughput and reduces the end to end delay.

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