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Chaotic Pulse Based Communication System Proposal

This submission proposes a Chaotic Communication System as an alternative PHY for IEEE 802.15.4a, with a focus on the band plan, Chaotic Pulse, PHY layer proposal, system performance, and simultaneously operating piconets.

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Chaotic Pulse Based Communication System Proposal

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Chaotic Pulse Based Communication System Proposal] Date Submitted: [4 January, 2005] Source: [Hyung Soo Lee (1), Cheol Hyo Lee (1), Dong Jo Park (2), Dan Keun Sung (2), Sung Yoon Jung (2), Chang Yong Jung (2), Joon Yong Lee (3)] Company[(1) Electronics and Telecommunications Research Institute (ETRI) (2) Korea Advanced Institute of Science and Technologies (KAIST) (3) Handong Global University (HGU)] Address[(1) 161 Gajeong-dong, Yuseong-gu, Daejeon, Republic of Korea (2) 373-1 Guseong-dong, Yuseong-gu, Daejeon, Republic of Korea (3) Heunghae-eup, Buk-gu, Pohang, Republic of Korea] Voice:[(1) +82 42 860 5625, (2) +82 42 869 5438, (3) +82 54 260 1931], FAX: [(2) +82 42 869 8038] E-Mail: [(1) hsulee@etri.re.kr, (2) syjung@kaist.ac.kr, (3) joonlee@handong.edu] Abstract: [The Chaotic Communication System is proposed for the alternative PHY for 802.15.4a] Purpose: [This submission is in response to the committee’s request to submit the proposal enabled by an alternate 802.15 TG4a PHY] 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.

  2. CFP Presentation for IEEE 802.15.4aAlternative PHY Chaotic Pulse Based Communication System Proposal Electronics and Telecommunications Research Institute (ETRI) Korea Advanced Institute of Science and Technologies (KAIST) Handong Global University (HGU) Republic of Korea

  3. Contents • Band Plan • Chaotic Pulse • PHY Layer Proposal • System Performance • Simultaneously Operating Piconets (SOPs) • Link Budget & Sensitivity • Ranging

  4. Low band 3 4 5 6 7 8 9 10 11 3 4 5 6 7 8 9 10 11 Band Plan • Bandwidth : Two bands - Low band (3.1 to 4.9 GHz) : Mandatory band - High band (5.825 to 10.6 GHz) : for future use High band

  5. Chaotic Pulse • Large base signal [base=2*bandwidth*duration] • Flexible bandwidth and signal duration • Low cost implementation

  6. Modulation Scheme • Multi-coded Pulse Position Modulation (MC-PPM) • It is power efficient scheme • It has inherent coding gain due to orthogonal multi-codes • It can support wide pulse spacing in same data rate condition • Less multipath interference between pulses • Good for non-coherent energy detection • No dynamic threshold problem • Disadvantage in On-Off Keying (OOK) based on non-coherent energy detection

  7. Multi-coded symbol ( Code rate : L/Ns ) Ex. Code rate = 3/4 1 1 -1 1 -1 1 -1 1 -1 -1 -1 1 1 1 1 -1 -1 -1 1 -3 1 1 1 -1 -1 1 1 -1 -1 1 1 Orthogonal code set ( Code Length : Ns ) Ex. Ns=4 Data block ( L bits ) Ex. L=3 Multi-Coded PPM (MC-PPM) • Operation example (L=3, Ns=4) * Ref : 15-04-0485-04-004a-multi-coded-bi-orthogonal-ppm-mc-bppm-based-impulse-radio-technology Modulation MC-PPM Signal : 1 -3 1 1

  8. : # of bits per data block ... : # of Repetitions : Orthogonal code length : # of repetitions : Orthogonal Code length ... : Pulse bin width (duration) : Multi-coded chip duration : Position number for MC-PPM : Multi-coded symbol duration ... : Guard time for processing delay : Total transmit time duration of a data block Data Frame Structure • Frame structure of PPDU • 1 data block (L data) interval of PSDU : Preamble SFD PHR PSDU 4 1 1 32

  9. Data Encoder Data Modulator Data Orthogonal Channel MC-PPM Multi-code Pulse Generator Data Data Decoder Energy Data DeModulator Orthogonal Detector MC-PPM Multi-code Location Detector Transceiver Architecture • Transmitter • Receiver

  10. PHY-SAP Data Rates • Flexible data rates can be supported according to several design parameter (Tm, L, Ns, Nr, Tg)

  11. ttx ∙∙∙∙ ∙∙∙∙ ∙∙∙∙ tlong_frame tACK tACK_frame LIFS Data Throughput • Transmission time (ttx) & Data throughput (Rth) • For L=3, Ns=8, Nr=1,Tg=0ns (457kbps) • ttx = tlong_frame + tACK + tACK_frame + LIFS • = 614.4 u + 25.6 u + 187.7 u + 85.3 u = 913 u • Rth = 32×8 / 913u ≈ 280.3 kbps ( Nominal throughput based on 32 bytes payload ) • For L=3, Ns=16, Nr=1,Tg=0ns (228kbps) • ttx = tlong_frame + tACK + tACK_frame + LIFS • = 1228.8 u + 51.2 u + 375.5 u + 170.7 u = 1826.2 u • Rth = 32×8 / 1826.2 u ≈ 140.2 kbps ( Nominal throughput based on 32 bytes payload )

  12. 32*8/3 Data Blocks 1 Packet Time Duration Comments on 1kbps PHY-SAP Data Rate • Burst Transmission Scheme << Example >> • L=3, Ns=8, Nr=1,Tg=0ns (457kbps) • L=3, Ns=16, Nr=1,Tg=0ns (228kbps)

  13. Signal Acquisition • Energy detection based acquisition • Acquisition should be performed in order to make synchronization and demodulate data • Procedure • If the output of energy detector exceeds the threshold level, we think that the signal is acquired. • Threshold level for acquisition • Determined relative to estimated noise level

  14. preamble preamble Synchronization • Non-coherent Synchronization Procedure • Assume Nint square-law integrator • Divide Tm time into total Nint time slots (each time slot contains Tm / Nint time) t_s : sync. starting point t_sync : exact sync. point

  15. Synchronization • Non-coherent Synchronization Procedure • The output value of n-th square-law integrator • Estimated synchronization point

  16. MC-PPM Performance : AWGN • BER & PER • L=3, Ns=8,Nr=1 (457kbps PHY-SAP data rate)

  17. MC-PPM Performance : 4a Channel Models • BER & PER • L=3, Ns=8,Nr=1

  18. Acquisition & Synchronization Parameters • System Parameters • Chaotic Pulse [BW=1.8GHz(3.1G-4.9GHz), Tp=20ns] • Preamble Length • 4 bytes (32 preamble symbols) • Tm=200ns, Ts=100ns (5 chaotic pulses of duration 20ns) • Preamble Time Duration = 32 symbols*200ns=6.4us • Num. of Integrator (Nint) = 10 • Assume that only 5 Integrator are implemented in HW • Actual Preamble Length = 32 Symbols/(Nint/5)=16 Symbols • Sync. Resolution Range = [-10ns, 10ns] • Threshold level for acquisition • Determined relative to the estimated noise level

  19. Acquisition Performance : AWGN • Comments • Acquisition performance is dependent on threshold level

  20. Synchronization Performance • Comments • Signal acquisition is assumed • Performance depends on Sync. Resolution Range

  21. Piconet#1 Active Inactive Piconet#2 Piconet #3 SOPs • Time Division • Operating bandwidth • 3.1-4.9 GHz can be fully used (Chaotic pulse) • Configuration of SOPs • Self configuration of SOPs is possible

  22. Self Configuration of SOP • Passive Scan • Repeat scaning one channel (3.1-4.9 GHz) • Usage • Starting a new piconet (FFD) • Association (FFD or RFD)

  23. Link Budget & Sensitivity

  24. Tround trip Tpropagation2 Packet 1 Packet 2 Node 1 t0 t3 t1 t2 Node 2 Packet 1 Packet 2 Tpropagation1 Tprocessing time Ranging Scheme • TOA/TWR (Two Way Ranging) • Measurement of Tround_trip

  25. Ranging Algorithm Potential lock point (peak) • Procedure (Algorithm) length of search region signal leading edge threshold level envelope detector output search for the 1st level-crossing point time (ns) • Search for the 1st level-crossing point at the threshold level in negative direction from the initial lock point • References: • Joon-Yong Lee and Robert A. Scholtz, "Ranging in a dense multipath environment using an UWB radio link" , IEEE Journal on Selected Areas in Communications, vol.20, no.9, pp.1677 - 1683, Dec. 2002 • Robert A. Scholtz and Joon-Yong Lee, "Problems in modeling UWB channels", 36'th Asilomar Conference on Signals, Systems & Computers, Nov. 2002

  26. Ranging Performance • Performance • 802.15.4a channel (cm4) • Single user • No narrowband interference • Pulse width = 20ns • Integration time = 2ns • Pulse repetition period = 200ns • Length of search region = 40ns • Threshold level was determined relative to noise floor • A separate envelope detector for range estimation was employed

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