In a CDMA system, the signal is spread over a large bandwidth by multiplying the transmitted symbol by a sequence of short pulses, also called chips. The system bandwidth is thus determined by the duration of a chip. If the chip duration is 0.26 ?s and the maximum excess delay is 1.3 ?s, into how many delay bins do the multipath components fall? If the maximum excess delay is 100 ns, is the CDMA systems wideband or narrowband?
Questions
Introduction
1) Write down the evolution of wireless mobile communication systems.
2) Draw a block diagram of cellular radio network.
3) Draw a timing diagram illustrating how a call to a mobile user is initiated by a landline subscriber.
4) Show the various upgrade paths for 3G technologies with a neat figure.
5) What is a cellular concept? How did it solve the problem of spectral congestion? Illustrate.
6) What is frequency reuse? Discuss the relationship between system capacity C and cluster size N with suitable derivation.
7) What is cell dragging? Illustrate umbrella cell approach.
8) Discuss co-channel and adjacent channel interferences?
Point to Multipoint System(PMP)
9) What is multiple access Method? Why is it necessary?
10) Discuss the multiple access techniques: TDMA, FDMA and CDMA in brief.
11) What is TDD and FDD? Illustrate.
Propagation Theory
12) What do you mean by multi-path propagation? Discuss a RAKE receiver with suitable diagram.
13) What is fading? Draw a tree diagram and discuss different types of fading in brief.
14) Discuss Hata Model and Okumura model.
15) Discuss space diversity considerations.
16) Differentiate between Equalization and Diversity technique.
Modulation Technique
17) Describe BPSK transmitter and receiver with the help of suitable block diagram.
18) What is coherent and non-coherent detection? List the advantage of DPSK over PSK.
19) Discuss QPSK with its constellation diagram.
GSM technology
20) Why and When GSM technology was introduced?
21) Discuss the services and features of GSM.
22) Explain GSM architecture in detail with diagram.
23) Discuss the various interfaces used in GSM with a diagram.
24) What is the modulation technique used in GSM? Discuss technical aspects of GSM radio subsystem.
25) Discuss frame and multiframe structure of GSM.
26) Present GSM air interface specifications summary with required parameters.
27) Differentiate between Full rate and Half rate traffic control channel.
28) Draw a tree diagram showing diffrernt channel types in GSM.
29) Discuss hands-off stragegy in cellular system.
30) Prove that for a hexagonal geometry, the co-channel reuse ratio is given by Q = √(3N), where N = i2+ij+j2. (Hint: Use cosing law and hexagonal cell geometry)
31) Draw the block diagram of Wireless Communication System and explain each block in detail.
32) Explain how frequency reusing is achieved in cellular systems and also explain the various methods for improving the capacity of a cellular system.
33) Discribe briefly the network architecture of a cellular mobile communication system.
34) Show that the frequency reuse factor for a cellular system is given by K/S, where K is average number of channels availabe to the cellulare service provider.
35) Briefly explain the channel assignment strategies in cellular communication.
36) Define traffic and Grade of Service(GOS). What are the assumptions based to derive Erlang B formula. State the Formula as well.
37) Explain the role of BTS and MSC.
38) Why adjacent channel interference is caused, what are the sources?
39) What are the factors affecting in the choice of digital modulation?
40) Explain the performance advantages of digital modulation over analog?
41) What is duplexing? What are the types of duplexing used in mobile communication system?
42) What is the advantage of multiple access schemes?
43) Derive path loss equation using free space propagation model.
44) Explain in brief about the hand-off strategies used in cellular communication system.
45) Why is hexagonal cell geometry chosen in cellular design?
46) Differentiate between TDMA,FDMA and CDMA.
47) List out the services that are provided in GSM.
48) Enumerate the latest advancement in mobile communication.
49) What is trunking theory? Why is the cell splitting and sectoring used?