1、1. why the cellular configuration is used for mobile communications.
2、2. 说明2g和1g系统主要区别，是否tdma可以用于模拟通信系统？
3、若小区族（cluster）含有7个小区，族的大小为7，路径损耗指数是4，计算信干比sir。若路径损耗指数为2，计算sir。 比较两种路径损耗指数下的sir并作简单解释。若小区半径为r=1 km, 计算最近的两个同信道小区之间的距离。
4、4. 分析移动通信系统发展的趋势
chapter2: wireless channel
第二章 测试
1、the cellular system configuration for mobile communications is proposed by a、hua wei b、ericssion c、bell lab d、simens
2、the fading due to shadow in mobile systems is usually modeled to satisfy a、gaussian distribution. b、uniform distribution. c、rayleigh distribution. d、log-normal distribution.
3、for the coherence time of channel, the correct statement is a、the maximum time interval within which the channel gain can be approximately taken as fixed. b、the minimum time interval within which the channel gain can be approximately taken as fixed. c、the maximum time interval within any such a duration the channel gain can be approximately taken as fixed. d、the minimum time interval within any such a duration the channel gain can be approximately taken as fixed.
4、if b and bc used to denote the bandwidth of the signal and the channel coherence bandwidth, respectively, the correct statement is that a、if b>bc, then the fast fading occurs. b、if b< bc. then the fast fading occurs. c、if b>bc. then the flat fading occurs. d、if b 5、if c and v denote the velocity of the radio wave and the mobile station, and is the wave length, then the maximum doppler frquency shift is a、 b、 c、 d、
1、explain the fast fading and the slow fading, and the effects of the maximum doppler frequency on fading.
2、1. consider the design of a high-quality direct broadcast satellite link operating at 4 ghz, transmitting a television signal with a bandwidth of 5 mhz. a typical noise temperature is of the order of 550 k. suppose the transmitter is transmitting 120 w and the antenna gain is 40 db, the satellite is at an altitude of 36000 km. what gain does the receiving antenna need to achieve an snr of 30 db? you may assume that the polarisation and medium losses are negligible.