多媒体宽带CDMA系统的功率分配和控制
摘 要
本文研究了多媒体宽带CDMA系统的功率分配和控制技术。文中指出多媒体宽带CDMA系统的单个小区中，当用户的服务质量由平均信干比要求给出时，功率分配问题是一个线性不等式方程组的求解问题；探讨了解存在的充要条件并求出了解；基于此解提出了新的功率控制方案。该方案与传统的功率控制方案的比较结果表明，新方案优于传统方案。另外，本文提出了同时考虑平均信干比条件和掉话率条件下的一种基于业务的非线性功率控制算法，该算法利用迭代，求得各业务到达基站时所需的最小功率，从而使系统容量达到最大，同时能保证各业务具有高服务质量。一个三业务系统的数值仿真，验证了此功率控制算法的优点并显示了服务质量与系统容量间的交换关系。最后，本文研究了同时考虑平均信干比和掉话率要求下功率控制算法的收敛性问题，找出了算法收敛的充分条件和必要条件，在此基础上提出了两种新的功率控制算法，并讨论了算法对系统容量的影响。数值结果表明，新算法1是QoS要求和系统资源的良好折衷，而新算法 2能提供更高的服务质量，但资源利用率不高。
关键词：码分多址，扩频通信，移动通信，功率控制，容量，多媒体。
论文类型：应用基础
Power Control and Assignment in Multimedia
Wideband CDMA Systems
ABSTRACT
Power assignment and control in multimedia wideband CDMA systems are studied. In this work, it is indicated that when one cell of multimedia CDMA system is considered, and if user’s requirement of quality of service (QoS) is given by average signal-to-interference ratio (SIR), power assignment is equivalent to finding the solution of a set of linear inequations. After the condition of the existence of solution is derived and the solution is obtained, a new power assignment scheme, which is better than the conventional one, is proposed. In addition, as we know, if user’s requirement of QoS is given by average SIR and outage probability, power assignment and control are nonlinear. An algorithm of traffic-based nonlinear power control is proposed. The minimum received power of each traffic type at base station is derived by iteration. As a result, the system capacity 无忧论文 【http://www.uklunwen.com】is maximized and high QoS is guaranteed. The simulation of a system involving three traffic types confirms the advantage of the algorithm and shows the trade-off between QoS requirement and system capacity. Further, the convergence condition for the nonlinear power assignment algorithm is studied. Two new algorithms are proposed based on the derived sufficient condition and necessary condition, respectively. The numerical results show that the first algorithm has an efficient utility of system resource in slight sacrifice of QoS requirements, and new algorithm 2 can provide higher QoS.
Keywords：CDMA, spread spectrum communications, mobile communications, power control, capacity, multimedia |
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论文题目：
多媒体宽带CDMA系统的功率分配和控制 
