SPPU Electronics and Telecom Engineering (Semester 6)

Information Theory and Coding Techniques

June 2015

Information Theory and Coding Techniques

June 2015

Answer any one question from Q1 and Q2

1 (a)
Design a Shannon-Fano code for a source generating 5 different messages with probabilities 0.45, 0.3, 0.15, 0.05, 0.05. Find the coding efficiency.

7 M

1 (b)
What are interleaved codes? Explain with suitable example.

7 M

1 (c)
Write the procedure for decoding a cyclic code.

6 M

2 (a)
What is Run length encoding? Explain how it is used in bitmap file formats.

7 M

2 (b)
What are single parity check codes? Write about the decoding performance of these codes.

7 M

2 (c)
What is CRC code? Explain how are they generated?

6 M

Answer any one question from Q3 and Q4

3 (a)
Find the generator polynomial for (7, 4) BCH code. Use primitive polynomial x

^{3}+x+1.
10 M

3 (b)
What are RS-codes? Write features & applications of Rs. Codes.

6 M

4 (a)
The received code polynomial for a (7, 4) BCH code is r(x)=x

^{6}+x^{4}+x^{3}+x^{2}. Find the corrected codeword polynomial if single error has occured.
8 M

4 (b)
What are cyclic hamming codes? Give one example of cyclic hamming code.

4 M

4 (c)
Explain stop-and-wait ARQ.

4 M

Answer any one question from Q5 and Q6

5 (a)
Draw state diagram for following convolutional encoder.

6 M

5 (b)
Explain with suitable example generator polynomial description of convolutional codes.

8 M

5 (c)
Write a short note on Turbo codes.

4 M

6 (a)
For the following convolutional encoder, find the coded output if input message is 10110000.

8 M

6 (b)
What is sequential decoding? Explain in brief.

6 M

6 (c)
Write a short note on LDPC codes.

4 M

Answer any one question from Q7 and Q8

7 (a)
Explain how the goals of the communication system designer are conflicting.

6 M

7 (b)
What is bandwidth efficiency plane? Explain different regions in the plane.

6 M

7 (c)
Write Ungerboeck's TCM design rules.

4 M

8 (a)
What is error probability plane? Indicate various trade-offs on this lane.

6 M

8 (b)
What is coding gain inTCM encoder? How it is calculated?

6 M

8 (c)
What are typical design specifications of communication system? What techniques are used when

i) Power is limited

ii) Bandwidth is limited

i) Power is limited

ii) Bandwidth is limited

4 M

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