Mobile Communication - May 2015

Electronics & Telecomm. (Semester 7)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.

1 (a) Derive relationship between S/I (Signal to interference radio) and cluster N. (5 marks)

1 (b) Explain HSCSD network. (5 marks)

1 (c) Explain Cell dragging in GSM. (5 marks)

1 (d) Explain hard hand-off and soft hand-off. (5 marks)

2 (a) Assume a receiver is located 10 kms from a 50W transmitter. The carrier frequency is 900MHz. Free space propagation is assumed, Gt=1 and Gr=2.
Find:
i) The power at the receiver.
ii) The magnitude of the E-field at the receiver antenna.
iii) The rms voltage applied to the receiver input assuming that the receiver antenna has a purely real impedance of 50 and is matched to the receiver. (10 marks)

2 (b) Explain in detail GSM network architecture. (10 marks)

3 (a) What is meaning of traffic channel, signaling channel, broadcast channels & common control channel w.r.t. GSM. (10 marks)

3 (b) Compare SDMA, TDMA, FDMA, CDMA techniques. (10 marks)

4 (a) Describe open loop and closed loop system of power control in CDMA system. (10 marks)

4 (b) Sketch the block diagram of reverse traffic channe of IS-95. Explain function of each block. (10 marks)

5 (a) How is power control applied in forward traffic channel of IS 95? (10 marks)

5 (b) Draw and explain GPRS architecture. (10 marks)

6 (a) Discuss in detail IMT 2000. (10 marks)

6 (b) Explain forward link features of CDMA 2000 and also explain basic service provided by upper layers of CDMA 2000. (10 marks)

Write short notes on following:

7 (a) Umbrella cell approach. (5 marks)

7 (b) Effect of Doppler spread on fast fading and slow fading. (5 marks)

7 (c) Rake receiver (5 marks)

7 (d) Hand off in GSM. (5 marks)