Download GTU BE/B.Tech 2019 Summer 7th Sem Old 171004 Wireless Communication Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER-VII (OLD) EXAMINATION — SUMMER 2019

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Subject Code: 171004 Date: 27/05/2019

Subject Name: Wireless Communication

Time: 02:30 PM TO 05:00 PM Total Marks: 70

Instructions:

1. Attempt all questions.

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2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

Q.1 (a) Compare 2G, 2.5G, 3G and 4G in brief. (07)

(b) Explain frequency reuse concept with suitable figure (07)

Q.2 (a) Define following: MAHO, RSSI, Cell Dragging, Coherence BW, Coherence Time, Cell, Cluster (07)

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(b) Prove that the co- channel reuse ratio is given by Q= v3N , where N = i²+ ij +j² (Use cosine law & hexagonal geometry) (07)

OR

(b) Explain the difference between cell splitting and sectoring. (07)

Q.3 (a) Explain Ground reflection (Two Ray) model and find E_ror in terms E-field at the reference distance d_r, Receiver distance and antenna height. (07)

(b) Describe the factors influencing and effect of small scale fading. (07)

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OR

Q.3 (a) Explain Impulse response model of a multipath channel. (07)

(b) Explain Diffraction of Radio Signals using Fresnel Zone Geometry. Show expression for nth Fresnel Zone circle in terms of ?, d1 & d2. (07)

Q.4 (a) Explain TDMA technique. What is frame structure of TDMA system? OR Show how to work out efficiency of TDMA system. (07)

(b) Write a S.N. on Zig Bee. (07)

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OR

Q.4 (a) Write S.N on Rake Receiver. (07)

(b) Describe Spread spectrum multiple access technique (FHMA & CDMA). (07)

Q.5 (a) Draw and explain GSM architecture. (07)

(b) Explain Security issues and challenges in a Wireless network (07)

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OR

Q.5 (a) Explain CDMA forward channel. (07)

(b) Discuss step by step signal processing in GSM. (07)

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