Mobile Communication - Dec 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) Compare 2G, 3G and 4G with respect to speed, applications and bandwidth.(5 marks) 1 (b) if 36 MHz total spectrum is allocated for a duplex wireless cellular System and simplex channel has 25 MHz RF bandwidth find Total number of duplex channels, Number of channels per cell if N=4 cell. reuse is used.(5 marks) 1 (c) Explain concept and importance of power control in CDMA.(5 marks) 1 (d) Explain fading effects due to Doppler spread.(5 marks) 2 (a) If a signal interference ratio of 15 dB is required for satisfactory Forward channel performance of a cellular system, what is frequency Reuse factor and cluster size that should be used for maximum capacity if path loss exponent is 1) n=3 and 2) n=4. Assume six first tier co channel cells & mobile unit is at the center of cell.(10 marks) 2 (b) Explain principle of Rake receiver in detail.(10 marks) 3 (a) An urban area has population of two million residents. Three competing trunked mobile networks 1 systems A, B, C, provide cellular service in this area. System A has 394 cells with 19 channels each. System B has 98 cells with 57 channels each; and system C has 49 cells each with 100 channels. Find the number of users that can be supported at 2% blocking if each user averages two cells per hour at an average call duration of 3 minutes. Assuming that all three trunked systems are operating at maximum capacity, compute the percentage market penetration of each cellular service provider Data: GOS=0.02;

Write a short note on any two of the following:

6 (a) Multi antenna Techniques.(10 marks) 6 (b) Cellular capacity and coverage improvement Techniques.(10 marks) 6 (c) Indoor propagation Models.(10 marks)