移动通信第讲.pptVIP

3.4 Traffic handling capacity: Erlang performance and cell sizing3．4 流量控制：爱尔兰厄兰性能和小区尺寸 With the appropriate cell cluster size or reuse parameter C determined, by the SIR required for a given system, the number of channels available per cell is immediately established. For example, the first-generation AMPS provides 832/C channels per cell, as already noted. With C = 7, as determined in the previous section, the system can provide 118 channels per cell. 一旦由系统给定的信干比决定的再用 参数C或小区簇的大小确定，有效的信道数 量也就确定了。例如，第一代AMPS系统每 个小区提供832／C个信道，这已经在前面 提到过。当C=7时，系统每个小区提供 118个信道。 Given the number of channels available per cell, we can now determine the geographical extent or size of cells. This determination is based on a consideration of the traffic expected in a given region and the system performance, other than SIR, that is to be provided to a typical user. 给定每个小区的有效信道数量，能确 定小区的地理范围和尺寸。在一个给定区 域和系统性能的情况下，主要考虑流量， 而不是信干比，信干比主要是针对每个特 定的用户而言的。 In this introductory section on system performance we focus exclusively（专有地，单独地） on the probability of call blocking as a measure of performance or user satisfaction. The call blocking probability has, historically, been the principal（主要的） measure of performance in telephone systems . Simply put, it describes the chance （可能性）that a user, attempting to place a call, receives a busy signal. 在这部分，我们将介绍一下体现了系统 性能和用户满意度的方法之一——呼叫阻 塞概率。 历来，呼叫阻塞率一直是电话系统性能 指标的主要测量方式。 简单地说，它是表征一个用户打算通话 但系统告知繁忙的可能性. In the mobile wireless domain the calculation of the call blocking probability in a given cell depends on the number of channels available and the traffic expected to use that cell. 在无线通信领域，给定一个小 区，呼叫阻塞概率的计算依赖于可以 同时处理的有效信道数量以及此小区 期望的流量. In the material（素材，资料） following, we first define what is meant by “amount of traffic（流 量） ,or traffic intensity ,or traffic load（负荷） ,using a simple statistical model, then indicate how the blocking probability is relat