【作者】 蔡敏；

【导师】 王伟；

【作者基本信息】 大连理工大学 ， 控制理论与控制工程， 2006， 博士

【摘要】 在移动通信系统中,传输功率控制是抑制共道干扰、克服“远近效应”、降低功率消耗、增加系统容量的重要手段,现已成为第三代(3G)移动通信系统的关键技术之一。功率控制方法主要有信干比(Signal-Interference Ratio)平衡法(SIR方法)和服务质量(Quality of Service)跟踪法(QoS方法),许多学者利用上述两种方法对移动通信系统功率控制问题进行了大量的研究,并提出了一些功率控制算法。在提出的功率控制算法中,多数算法均假设链路增益、信干比、干扰功率是确定的。但是对于实际移动通信系统,获得上述这些量的精确值几乎是不可能的。因此,在确定条件下得出的一些功率控制算法无法应用于实际。本文充分考虑了移动通信系统的随机和时变特性,结合随机逼近理论和矩阵分析理论,对移动通信系统的功率控制问题进行深入系统的研究。主要工作如下: 研究了移动通信系统随机功率控制问题。其中包括在假设用户匹配滤波器输出已知、链路增益具有随机估计误差、信干比具有乘性噪声情形下的随机功率控制算法。并利用随机逼近理论证明了上述三种情形下提出的算法的收敛性。 对于实际移动通信系统,干扰功率是随机的,其精确值几乎无法获得,在假设干扰功率具有随机估计误差的情形下,提出一个基于干扰估计的随机功率控制算法。通过随机逼近理论把功率控制问题转化为寻求一个特定函数的零点问题,并证明了提出算法的收敛性。 对于一个大而有限的CDMA蜂窝系统,提出了一个分散定步长的控制算法,此算法是一个反馈调节算法。在假设系统链路增益时变、有界的情况下,证明了每一用户的传输功率均收敛,每一用户的信干比收敛于由步长和信干比目标值所决定的目标域之内。 大多数功率控制算法均需几个比特来发送功率控制命令。本文考虑链路增益时变情况下的功率控制问题,给出了一个二进制反馈功率控制算法,并证明了算法的收敛性。此算法仅需一个比特来发送功率控制命令,可以应用于实际的移动通信系统。更多还原

【Abstract】 Transmitter power control has been proven to be an important means in suppressing co-channel interference, combating near-far problem, lowering power consumption and increasing systems capacity. It has been one of the key technologies in 3G mobile communication systems. Power control methods mainly include Signal-Interference Ratio balancing and Quality of Service tracing. Many scholars have done a great deal investigations for the power control problems in the mobile communication systems and have obtained some power control algorithms. Most of these power control algorithms assume that link gain, signal-interference ratio and interfemce power are some fixed quantities. However, estimating these quantities perfectly is impossble in practice, Some power control algorithms obtained in case of certain conditions can not be applied in practice. The stochastic and time-varying characteristics of mobile communication systems are considered in this dissertation, the power control problems are studieded with stochastic approximation theory and matrix analysis theory. The main work of this dissertation is as follows.The stochastic power control problems of mobile communication system are studied in this dissertation, the three power control algorithms are presented for user with the certain matched filter output, link gains with the stochastic estimation error and SIR with multiplicative noise. The convergence of algorithms is proved by the classical stochastic approximation theory.The interference power is a stochastic process and it is a formidable task to measure it in practice. A power control algorithm based on the interference estimation is presented in this dissertation, it is shown that power control problems can be converted to a zero point problem of a specific founction and the convergence of algorithms is proved by the mathematics induction.A distributed fixed-step power control algorithm is presented for a large CDMA cellular system and is a feedback-modulating algorithm. It is shown that transmitter power of each user converges to a fixed point and the received SIR of each user falls within a certain target region that is determined by a power control step-size and an SIR target.Most of power control algorithms need several bits to be used for sending the power control command back to each user. In this dissertation, a binary feedback power control is presented when link gains are assumed to be time varying and only one bit is sent back to each transmitter. The convergence of proposed algorithm is proved and the proposed scheme can be adopted in practical mobile communication systems.更多还原