A Modified Non Coherent PN Code Acquisition Scheme

Rethnakaran P

UbiNetics

E-Mail: ratna.p@ubinetics.com, ratnu@ieee.org

Joint work with

P.K.Venkataraghavan PK (Synopsys Inc) and

Tapan Ray (Wipro Technologies)

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Agenda

• Acquisition Problem

• Existing solutions

• Modified Non-coherent Detection scheme

• Performance Analytical, Simulation results

• Summary

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DSSS System (Transmitter)

• Transmit Signal

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DSSS System (Receiver)

• Received Signal

• Down Converted I-Q

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Acquisition Problem

• Identify (Detect) the transmitted PN code (Code Phase)

from the received (I and Q) signals,

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System Model

• Receiver Structure

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Non Coherent Detection Scheme

• Non Coherent Detector Structure

• Why Non Coherent?Unknown Random PhaseData modulation yet to be removed

• PenaltyCompared to Coherent scheme

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Modified Non Coherent Scheme

• DNC Structure

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System Model (Continued)

• Post Detection IntegrationNo Post Detection (L=1)

• Matched Filter Based ReceiverPN Sequence used

• AWGNNo Fading

• DSSS/BPSK

• Performance Criteria – ROCProbability of Detection Vs Probability of False Alarm

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Analytical Results (ROC)

• False Alarm Probability

• Probability of Detection

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Performance (NC Versus DNC)

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DNC Advantage (Over NC)

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Simulation Results

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Summary

• New Structure Proposed

• Analytical Expressions (ROC) Derived

• 2dB SNR Advantage Over Conventional Non Coherent Scheme

• Supported by System Level Simulations

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Q&A

Thank YouRethnakaran P

UbiNetics

E-Mail: ratna.p@ubinetics.com, ratnu@ieee.org

http://ratnu.tripod.com

http://www.ubinetics.com