多対多通信を用いたコンピュータネットワークの性能評価に関する研究

我们一直专注于DS-CDMA（直接序列码分多址）系统与完美/不完美的功率控制，和重叠结构的干扰抑制。基于IS-95协议，提出了一种分层的反向链路蜂窝模型，其中假设接收信号服从对数正态分布，并采用多波束天线进行小区划分。研究了系统在完全/不完全功率控制和完全/不完全扇区划分情况下的容量平面和中断概率。根据我们的数值结果，我们可以增加系统容量的2.3倍以上的非分层蜂窝系统。对于功率控制的前向链路，本文还提出了一种分级系统的性能评估方法。传播特性被假定为对数正态统计。研究了宏小区和微小区的系统容量和中断概率。系统容量比非分层系统提高了3.1倍.研究了采用干扰抑制技术的TDMA/W-CDMA和N-CDMA/W-CDMA频谱重叠系统的可行性。在假设系统具有理想功率控制的情况下，研究了系统在轻微阴影衰落和严重阴影衰落两种情况下的容量权衡和频谱效率。我们引入陷波滤波深度p和信号电平限幅深度q。根据数值计算结果，可以灵活地选择p和q，以确保更高的频谱效率。

We have been focusing on DS-CDMA(Direct Sequence-Code Division Multiple Access) systems with perfect/imperfect power control, and overlaid structures with interference suppression.1. Wireless systems with perfect/imperfect power control and sectoringBased on the IS-95 protocol, a hierarchical cellular model of the reverse link is proposed, in which we assume that the received signal follows log-normal statistics, and the multi-beam antennas are employed to divide the cells. The system capacity plane and the outage probability are examined and quantified when the system is with the perfect/imperfect power control and the perfect/imperfect sectorization. According to our numerical results, we can increase the system capacity 2.3 times more than the one of the nonhierarchical cellular system. A method for the performance evaluation of the hierarchical system is also proposed for the forward link with the power control. The propagation characteristic is assumed as the log-normal statistics. The system capacity and the outage probability of macrocell, and microcell areinvestigated. The system capacity can be increased 3.1 times compared with that of the nonhierarchical system.2. Overlaid cellular systems with interference suppressionWe investigate the feasibility of the spectrum overlaid systems of TDMA/W-CDMA and N-CDMA/W-CDMA, in which the interference suppression technologies are adopted. When the systems are assumed with the perfect power control, the system capacity trade-offs and the spectrum efficiency are studied when the systems are with both slight and serious shadow fadings. We introduce the notch filtering depth p and signal level clipping depth q. According to the numerical results p and q can be flexibly selected to ensure higher spectrum efficiency.