課程名稱︰行動通訊
課程性質︰選
課程教師︰陳光禎
開課學院：電機資訊學院
開課系所︰電信所
考試日期（年月日）︰100/12/08
考試時限（分鐘）： 120min
是否需發放獎勵金： yes
（如未明確表示，則不予發放）
試題 :
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
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.112.21.191