Download AKTU B-Tech 8th Sem 2015-16 EEC 801 Wireless Mobile Communication Question Paper

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Paper ID: 131801 EEC-801

Roll No.

B.TECH.

Theory Examination (Semester-VIII) 2015-16

WIRELESS & MOBILE COMMUNICATION

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Time: 3 Hours Max. Marks : 100

Section-A

Q1. Attempt all parts. All parts carry equal marks. Write answer of each part in short. (2×10=20)

1. (a) Find the number of duplex channels, if 20MHz of total spectrum is allocated for a duplex wireless cellular system and each simplex channel has 25 KHz RF bandwidth.
2. (b) What is fading?
3. (c) Compare the different second generation mobile communication systems, particularly in terms of multiple access technology, modulation technique and channel Bandwidth.

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4. (d) What is Doppler shift?
5. (e) What is difference between fast fading and slow fading?
6. (f) What is meant by coherent and non-coherent detection?
7. (g) Explain the function of Forward and Reverse control channels.
8. (h) What is frequency reuse? Explain.

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9. (i) What is diversity? What are different types of diversity techniques?
10. (j) What is cell splitting?

Section-B

Q2. Attempt any five questions from this section. (10x5=50)

1. (a) How is frequency selective channel different from frequency non-selective channel?
2. (b) How IMT-2000 is useful for node to node communication?

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3. (c) Consider a GSM system, which is a TDMA/FDD system that uses 20 MHz for forward link which is broken into radio channels of 200kHz and if no guard band is assumed, find the number of simultaneous users that can be accommodated in GSM.
4. (d) Write range of frequency for forward and reverse link operation for IS-95.
5. (e) A receiver in an urban cellular radio system detects 1mW signal at d=d0=1m from the transmitter. In order to mitigate co-channel interference effects, it is required that the signal received at any base station receiver from another base station transmitter which operates at the same frequency should be equal to 1µW or less. A mobile radio system uses two 50 KHZ simplex channel to provide full duplex voice and control channels. Assume that the system uses nine cell reuse pattern and 1MHz of the total bandwidth is allocated for control channels. Also calculate the number of control channels and voice channels per cell.
6. (f)
   1. (i) Show that an equalizer is an inverse filter of the channel.
   2. (ii) Draw the Block diagram of LPC system and explain it.

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7. (g) Derive an expression for selection diversity improvement in terms of probability of receiving signal using single branch or using M branches.
8. (h) Prove that in the two ray ground reflection model, A = d?¹ – d² = 2 ht*hr / d. Show when this holds as a good approximation.
9. (i)
   1. (i) What is basic concept of Add-hoc network? Why and how proper route is required to discuss in addhoc network?
   2. (ii) Explain in brief 4G technologies and also compare with 1G, 2G and 3G technology.

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10. (j)
    1. (i) Explain various important parameters of power delay profile of multipath channel.
    2. (ii) Assume a receiver is located 10 km from a 50 W transmitter. The carrier frequency is 900 MHz, free space path loss model is appropriate for this system. Find the received power in dBm. Also find the factors affecting man scale rating.
11. (k) Write short notes on following
    1. (i) Cell sectoring

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    2. (ii) Co-channel Interference
12. (l) Explain different types of cell splitting. If i, j are non-negative integers which describe the geometry relation between adjacent cells.

Section-C

Attempt any two questions from this section. (15×2=30)

1. Q3. (a) How priortizing Handoffs technique is used to decrease the probability of forced termination of a call due to lack of available channels?
   

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   (b) Discuss Umbrella cell approach with diagram to enhance the connectivity in mobile communication.
2. Q4. (a) Explain signal processing and GSM operations from speech input to speech output with diagram.
   (b) Consider a CNN system which is a TDMA/FDD system that uses 20 MHz for forward link which is broken into radio channels and if no guard band is assumed, find the number of simultaneous users that can be accommodated in GSM.
3. Q5. (a) Explain various applications and service of Next Generation Network (NGN).
   (b) Draw and explain the component of mobile network structure of IMT-2000.

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