课程名称︰行动通讯 课程性质︰选 课程教师︰陈光祯 开课学院：电机资讯学院 开课系所︰电信所 考试日期（年月日）︰100/12/08 考试时限（分钟）： 120min 是否需发放奖励金： yes （如未明确表示，则不予发放） 试题 : 1.[Frequence Reuse] 25% Frequence reuse is the fundemental concept for celluar communication. Assumeing the base station is located in the center of the cell, (a)please explain 4-cell and 7-cell reuse patterns. (b)Suoopse the radius of the cell is R and the distance between two nearset base station using the same frequency is D. D/R is a good index for co-channel interference. Please calculate D/R for 4-cell and 7-cell frequency reuse patterns. (c)D/R should be as large as possible. Is it true? WHY? (d)For a GSM system deploying 4/12 frequwncy reuse pattern, what is the maximun number of voice calls for a 5M Hz (in pair) bandwidth. (e)For IS-95 CDMA celluar, what is the frequency reuse factor? What is the potential source to have co-channel interference in this case? 2.[Spreading Codes] 20% In direct sequence spread spectrum communication and CDMA systems, we have to employ a spreading code. (a)Please find the autocorrelation for spreading code "1110010". Please verify whether this code satisfy the run-length property of random nature. (b)IS-95 uses Walsh-Hadamard sequence to support orthogonal signaling in synchornous systems. Please generate such sequence of length 8. (c)In IS-95, how to manage the spreading code for a user during the handover process? (d)3G WCDMA adopts OVSF codes to support multi-rate communications. Please generate such code sequence of maximun length 8. Please explain how to match transmission rates and codes. 3.[Celluar Systems] 30% (a)In GSM, what is the purpose for paging channel? What's the purpose for random access channel? How can we determine the maximun cell size for GSM? (b)3GPP R99 adopts ARM for speech coding. Please explain how it works to compromise source coding and channel coding. (c)What are the major functions in layer 3 for celluar such as GSM? please briefly explain. 4.[Network Architecture] 25% Please draw the block diagram of network architecture for the following systems (a)-(d) and explain their evolution to 3G LTE (a) GSM (b) GPRS (c) Iridium System (d) 3GPP WCDMA (e) please compare the handover among GSM, WCDMA, HSPA --

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