- Design Principles
Techniques - Problems
1. With the help of diagrams
discuss the principle of operation of the following multiple access
a) Frequency Division Multiple Access
b) Code division multiple scheme
c) Various Alloha Schemes
Mention the advantages and limitations of each.
2. Suggest possible satellite
multiple accessing techniques for the following applications giving
reasons for your choice.
a) An international FSS network.
b) A MSS network
3. Discuss the suitability of
each multiple access scheme for the return link of a V-SAT network.
Suggest a possible solution.
4. Describe the operation of
a pre-assigned TDMA system. Illustrate a typical TDMA frame structure.
Mention the advantage of TDMA over FDMA.
What do you understand by;
(i) bandwidth limited system
(ii) power limited system
b) Determine the TDMA transmission
capacity of a transponder with the following characteristics: Transponder
bandwidth (BT)= 72 MHz
Modulation = QPSK
Bt/Rb = 1.2 where Rb is the symbol rate.
c) Determine the TDMA capacity
of a four GHz link with the following characteristics:
Satellite EIRP = 22.5 dBW
Path loss = 197 dB
G/T of earth station = 30 dB/K
Total link margin = 5dB
Required Eb/No = 8.5 dB
d) What is the voice channel
capacity of a TDMA system with the following characteristics: Transmission
bit rate = 60 Mbps
Voice channel bit rate = 64 Kb/s
Number of bursts/frame = 10
Number of bits in each preamble = 150
Frame time (micro seconds) = 750