JNTU
JNTU B.Tech III SPREAD SPECTRUM COMMUNICATIONS Previous Question Paper (May - 2019 - R16)
Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART - A
Write the classification of direct sequences spread spectrum.
Answer
Direct Sequence Spread Spectrum (DSSS) is primarily classified based on the modulation technique used: BPSK-DSSS (Binary Phase Shift Keying) and QPSK-DSSS (Quadrature Phase Shift Keying).
Define code division multiple access.
Answer
Code Division Multiple Access (CDMA) is a channel access method where multiple users share the same frequency spectrum simultaneously. Each user is assigned a unique, orthogonal spreading code that allows the receiver to extract the intended signal while treating other users' signals as low-level background noise.
Explain about frequency hopping.
Answer
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Explain Delay Locked Loop.
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What is initial synchronization?
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Explain about spreading code.
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List the features of CDMA.
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Define mobile channel.
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Explain about forward error correction.
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Define jammers.
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PART - B
Explain the modulation and demodulation of direct sequence spread spectrum.
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Discuss the overall direct sequence system with waveforms.
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Compare process gains available for various techniques including signal rejection and cancellation.
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With neat block diagram, explain the frequency hopped spread spectrum system model.
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Explain about Double Dither Non-Coherent Tracking Loop.
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Write the concept of Tracking and explain Delay-Lock-Tracking.
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Explain briefly synchronization by Estimated the Received Spreading Code.
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Explain Serial Search Synchronization Techniques.
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Explain the design of Single-user receiver in a Multi-user channel with respect to CDMA.
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Discuss about multi user detection in CDMA cellular radio.
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Explain how viterbi algorithm performing maximum-likeli-hood decoding of convolution codes.
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Discuss the following:
Elementary convolution coding concept.
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Decoding and Bit-Error Rate.
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