Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

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Project IEEE P802.15 Working Group for Wireless
Personal Area Networks (WPANs) Submission Title
Samsung DM RD Center Proposal Date Submitted
XX December, 2004 Source Namhyong Kim et al.,
Samsung Electronics Digital Media RD
Center Address 416 Maetan 3 Dong, Yeongtong Gu,
Suwon City, Gyongi Do, Korea, 443-742 Voice 82
31 200 8783, FAX [phone] , E-Mail
namhyong.kim_at_samsung.com Re Response to Call
for Proposals Abstract Purpose Proposing a
PHY-layer interface for standardization by
802.15.4a Notice This document has been
prepared to assist the IEEE P802.15. It is
offered as a basis for discussion and is not
binding on the contributing individual(s) or
organization(s). The material in this document is
subject to change in form and content after
further study. The contributor(s) reserve(s) the
right to add, amend or withdraw material
contained herein. Release The contributor
acknowledges and accepts that this contribution
becomes the property of IEEE and may be made
publicly available by P802.15.
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• Samsung DM RD Center Proposal
• Multiple Access and Range Methodology
• for Chaos DCSK System
• Namhyong Kim, Inhwan Kim
• Samsung Electronics Co., Ltd.
• DM RD Center

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Contents

• Overview
• Chaotic System Simulator
• Chaotic Sources
• DCSK ( Differential Chaotic Shift Keying )
• Issues result from Chaos Signal
• Range Estimation based on Chaos Signal
• Conclusion

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Overview

• Chaotic Communication Simulator
• System Parameters
• Chaotic Source
• Modulation
• Issues
• Simultaneously Operating Piconets
• Range Estimation
• High precision Distance Measurement by TOA

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Contents

• Overview
• Chaotic System Simulator
• Chaotic Sources
• DCSK ( Differential Chaotic Shift Keying )
• Issues result from Chaos Signal
• Range Estimation based on Chaos Signal
• Conclusion

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Simulation Parameters

• Frequency Band
• Bandwidth 2 GHz
• Center Frequency 4 GHz
• Bit Frame
• 1 bit time frame 200 ns (5 MHz)
• Duty Cycle 50 (100 ns)
• Sampling
• Simulation Sampling Frequency 40 GHz

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• Chaotic Sources
• Pseudo-random Sequence
• Ordinary Differential Equation

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Pseudo-Random Sequence

• Pseudo-Chaos Signal Generator
• Pseudo-random Sequence filtered by Chebyshev
  Type I
• Pseudo-random numbersranging between -1.0 to
  1.0
• Chebyshev Specification
• Passband 0.15 lt f lt 0.25
• Stopband f lt 0.14 or 0.28 lt f
• Ws Attenuation 15 dB
• Wp Ripple 1 dB

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Chaotic Signal Characterictic(1)

• Regulated Spectrumby Filtering
• However, at most,Quasi-Chaos Source

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2nd Order Differential Equation with 4.5 Freedom
Runge-Kutta Method x1' (mF(x5) - X1)/T
x2' ?22(X1- X3) x3' X2 - a2X3 x4' a2x3'-
?22X5 x5' X4 - a2X5 x2'' a2x5'- ?32X7 x3'' X6
- a2X7 x4'' a4x3''-?32X9 x5'' X8 - a4X9

• Tx1' x1 mF(x5)
• x2'' a2 x2' ?22x2 ?22x1
• x3'' a3 x3' ?32x3 a3 x2'
• x4'' a4 x4' ?42x4 a4 x3'
• x5'' a5 x5' ?52x5 a5 x4'
• where,
• F(x) xe1- x-e10.5(x-e2- xe2)
• m110, ?20.3, ?30.7, ?40.7,
• ?50.6, ?21, ?30.86, ?40.73,
• ?50.6, T1.25, e10.5, e21

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Chaotic Signal Characterictic(2)

• Chaotic Signal directlygenerated from ODE45
• Direct UWB signal madefrom simple TR
  RLCcircuitry analyzable by2nd order
  differential equation

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• Modulation
• Differential Chaotic Shift Keying

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DCSK System Schematics
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Differential Operation
Template Bit
Original Frame
Multiplication
Half bit duration Delayed Frame
Half bit duration Integration
1 0
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Time Slot Jittered
300 ps Jitter
No Jitter
200 ps Jitter
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DCSK Performance (32 Octet)
BER
PER (200 Frames)
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Contents

• Overview
• Chaotic System Simulator
• Chaotic Sources
• DCSK ( Differential Chaotic Shift Keying )
• Issues result from Chaos Signal
• Range Estimation based on Chaos Signal
• Conclusion

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Strong Features

• Flat spectrum generated by unpredictable genuine
  random sequence
• Nearly infinite resourceful orthogonal code sets
  
• Immunity against multi-path fading
• Low complexity and cost circuitry from direct
  generation of UWB signal
• Good signal spectrum nature from Bandwidth/Bit
  rate gt 1

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Weak Features

• Nearly impossibility of the Same Signal
  Regeneration
• Impossible to brew the same signal template in
  the receiver side
• Hard to resolve Multiple Access/Simultaneous
  Operating Piconet and High resolution Range
  Problem
• High Sampling Problem from UWB (gt 2 GHz)
• Difficult to apply accurate estimation method
• Location Awareness/Range Problem

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SOP options for Chaos System

• Code Division
• High Sampling Clock
• High Cost and Overhead
• Frequency Division
• Range Resolution Degradation
• Almost only solution for 3 4 piconets in 3 5
  GHz band
• Time Division
• No fit in SOP Physical Selection Criterion due
  to Uncoordinated Piconets
• Possible solution under Assumption of Global
  time synchronization low duty cycle

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• Time Division SOP

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System Block
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Transmission
Frame1
Frame2
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Receiver Details
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Signal Processing
User1 1100111110
Multi_path Channel
User2 1101110110
User3 0100111010
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Contents

• Overview
• Chaotic System Simulator
• Chaotic Sources
• DCSK ( Differential Chaotic Shift Keying )
• Issues result from Chaos Signal
• Range Estimation based on Chaos Signal
• Conclusion

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Range Block Diagram
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(No Transcript)
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Time Counter Adjust Example
Device (-2 Offset)
Coordinator
Initial 356
358
1st Pass 364 ? 3568
374 ? 35816
1. PNC recalculates Device Arrival time 366 ?
358 (16/2) 2. Compare value from 1 and Device
-2 ? 364 366 3. 2 Transferred as Offset 4.
8 Kept for Distance between PNC and Device
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Location Awareness Special Mode

• Timing Counter Fine Synchronization
• PNC disseminates special frame to inform
  Deviceof Location special mode
• Device acknowledges with its own timing count
• PNC compares its own count with Devices
  count,and extract an offset between them
• PNC sends negative offset in order for Device
  tocompensate its timer
• Device informs PNC of all being set

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Template Frame
Data Frame
? X
? Y
Envelop Detection
Delay Circuit by 13 ns
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Fine Precision TOA Estimation

• Suggest Special mode different from Normal mode,
  which needs faster clock
• In special mode, Estimate how far Signal detached
  from fixed time slot with finer clock
• This obtained value returned with
  Responsecommand to Request command from MAC

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Delay Circuit
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Simulation (BNR 16dB)
Maximum Index of Moving Average by duty
cycle Duration will be converted to distance.
real distance 0.968 meter 2.5 ns precision
distance 0.750 meter Error -0.218 meter
real distance 13.118 meter 2.5 ns precision
distance 12.750 meter Error -0.367 meter
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Conclusion

• Chaotic Communication System Simulator
• Source Generation
• DCSK modulation
• Chaos System Issues
• Chaos Signal Features
• SOP solutions
• Ranging
• Fine distance estimation by using Chaos Signal

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References

• Kolumbán, G., Kennedy, M.P., Jákó, Z. and Kis,
  G., "Chaotic Communications with Correlator
  Receivers Theory and Performance Limits,"
  Special Issue of The IEEE Proceedings on chaotic
  communications, 2002.
• Kolumbán, G. and Kennedy, M.P., "Correlator-Based
  Chaotic Communications Attainable Noise and
  Multipath Performance," in "Chaos in Circuits and
  Systems," (G. Chen editor), Birkhauser, Boston,
  2002.
• Dmitriev A.S., Efremova E.V, and Maksimov N.A.
  Controlling the spectrum envelope in
  single-transistor generator of chaotic
  oscillations, Radiotekhnika i elektronika, 2004,
  vol. 49, no. 2, pp. 222-227 (in Russian).
• Dmitriev A.S., Kyarginsky B.Ye., Panas A.I., and
  Starkov S.O., "Experiments on ultra wideband
  direct chaotic information transmission in
  microwave band", Int. J. Bifurcation Chaos,
  2003, vol. 13, No. 6, pp. 1495-1507.