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

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ TDOA/TWR Positioning and Ranging Techniques Based on Noncoherent OOK PHY] Date Submitted: [09 NOV , 2004]

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

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [TDOA/TWR Positioning and Ranging Techniques Based on Noncoherent OOK PHY] Date Submitted: [09 NOV, 2004] Source: [Kwan-Ho Kim(1), Sungsoo Choi(1), Youngjin Park(1), Hui-Myoung Oh(1), Yo-Ahn Shin(2), Wonchul Lee(2), and Ho-In Jeon(3)] Company: [(1)Korea Electrotechnology Research Institute(KERI), (2)Soongsil University(SSU), and (3)Kyoungwon University(KWU)] Address: [(1)665-4, Naeson 2-dong, Euiwang-City, Kyunggi-do,Republic of Korea (2) 1-1, Sangdo-5-dong, Dongjak-Gu, Seoul, Republic of Korea (3)San 65, Bok-Jeong-dong, Seongnam, Republic of Korea] Voice:[(1)+82-31-420 6183, (2)+82-2-820-0632, (3)+82-31-753-2533], FAX: [(1)82-31-420 6183, (2)82-2-821-7653, (3)+82-31-753-2532], E-Mail:[(1)yjpark@keri.re.kr, (2)yashin@e.ssu.ac.kr, (3)hijeon@kyung won.ac.kr] Re: [] Abstract: [This document proposes preliminary proposal for the IEEE 802.15.4 alternate PHY standard.] Purpose: [Preliminary Proposal for the IEEE802.15.4a standard] 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. K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  2. TDOA/TWR Positioning and Ranging Techniques Based on Noncoherent OOK PHY KERI-SSU-KWU Republic of Korea K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  3. Contents • Noncoherent OOK UWB transceiver with power detection • Three modes in the receiver for system performance improvement • Asynchronous ranging by round trip time • Positioning based on sequential relay transmission • Positioning scenarios according to network topologies • Parallel window bank for power detection & ranging accuracy improvement K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  4. Proposal Overview(1) • Motivation of proposal • To satisfy IEEE 802.15.4a technical requirements, it is essential that low power consumption in the UWB system level as well as link level must be achieved • Conventional coherent UWB system based on correlator in the receiver can provide fairly good performance • However, coherent UWB system is very sensitive to the signal synchronization, and the additional pulse generator is required in the receiver • Thus, this system may increase the implementation complexity, and consequently power consumption and system cost • To meet low power and low cost requirement, we propose UWB system with OOK (On-Off Keying) modulation and noncoherent detection K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  5. Proposal Overview(2) • Pros & cons • In the proposed UWB system, unlike the conventional coherent UWB system, the signal demodulation is performed by simply comparing the received signal power with detection threshold • It can significantly relieve the strict synchronization requirement in the receiver and also provide with simplified transceiver structure with the minimal power and cost demand, since pulse generator is omitted • However, the noncoherent OOK UWB system may yield degraded • Bit Error Rate (BER) performance • Performance improvement for the noncoherent • OOK UWB system is essential K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  6. Proposed Noncoherent OOK UWB System Non-coherent OOK UWB system based on noise power calibration and signal power detection Data repetition and multipath combining for performance improvement Three modes in the receiver for compensation of performance degradation (calibration/timing/operation) UWB Transmitter Pulse Generator Input Bit Data OOK Sequence Repetition Modulation Calibration Mode ( C a l Threshold Noise i b Control Measuring r a t i o n M o / Timing Mode d T e i m S i Coarse Pulse Position Estimation w n i g t c / h Operation Mode O p e r P a o t Receiving i w Multipath o e Data n r Combining ) Gathering D e t e c t i o n Decision Output Bit Stage Sequence UWB Receiver K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  7. Pulse Repetition Based on Edge Triggering Pulse repetition for data transmission • OOK modulation can be easily implemented by generating UWB pulse based on edge triggering K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  8. Proposed Three Modes in the Receiver Signal processing in three modes Calibration Mode Timing Mode Operation Mode (R=2) Receiving Data Preamble Gathering Transmission Signal Interval “1” “1” “0” Multipath Noise Only (No Data) Combining Noise Power Level Coarse Estimation Demodulation of the Measurement by of Pulse Position & Received Signal Based Buffering & Averaging Peak Sample Position on Power Detection Final Bit Decision by Threshold Reset Multipath Combining & for Bit Decision Receiving Data Gathering K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  9. More Details in the Operation Mode (1) Operation mode description Simple • Decision statistics • : Number of pulse repetitions per data bit • : Number of multipath components for combining • : Received signal power corresponding to the ’th path • of the ’th transmitted pulse K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  10. More Details in the Operation Mode (2) • Threshold value for bit decision (no pulse repetition & no multipath combining) • : Parameter relative to the average power and power • variance of the first path • : Noise power measured by noise calibration mode • Threshold value (pulse repetition & multipath combining) • Threshold value (only pulse repetition) K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  11. Asynchronous Ranging Scheme • Synchronous ranging • One way ranging • Simple TOA/TDOA measurement • Universal external clock • Asynchronous ranging • Two way ranging • TOA/TDOA measurement by RTTs • Half-duplex type of signal exchange TOF : Time Of Flight RTT : Round Trip Time SHR : Synchronization Header But, High Complexity Asynchronous Ranging Synchronous Ranging K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  12. Proposed Positioning Scheme Features- Sequential two-way ranging is executed via relay transmissions- PAN coordinator manages the overall schedule for positioning- Inactive mode processing is required along the positioning- PAN coordinator may transfer all sorts of information such as observed - TDOAs to a processing unit (PU) for position calculationBenefits- It does not need pre-synchronization among the devices- Positioning in mobile environmentis partly accomplished P_FFD3 P_FFD2 TOA 24 TOA 34 RFD PAN coordinator TOA 14 PU P_FFD : Positioning Full Function Device RFD : Reduced Function Device P_FFD1 K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  13. Process of Proposed Positioning Scheme TOA measurement K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  14. RTT12 = T + 2T12 RTT23 = T + 2T23 RTT13 = T12 + 2T + T23 + T13 More Details for obtaining TDOAs • Distances among the positioning FFDs are calculated from RTT measurements and known time interval T • Using observed RTT measurements and calculated distances, TOAs/TDOAs are updated T12 = (RTT12 – T)/2 T23 = (RTT23 – T)/2 T13 = (RTT13 – T12 – T23 – 2T) RTT34 = T34 + T + T34 TOA34 = (RTT34 - T)/2 RTT24 = T23 + T + T34 + T + T24 TOA24 = (RTT24 - T23 - TOA34 - 2T) TOA14 = (RTT14 - T12 - T23 - TOA34 - 3T) RTT14 = T12 + T + T23 + T + T34 + T + T14 TDOA12 = TOA14 – TOA24 TDOA23 = TOA24 – TOA34 K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  15. Position Calculation using TDOAs • The range difference measurement defines a hyperboloid of constant range difference • When multiple range difference measurements are obtained, producing multiple hyperboloids, the position location of the device is at the intersection among the hyperboloids K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  16. PAN Coordinator FFD RFD Positioning FFD(P_FFD) Positioning Scenario Overview • Using static reference nodes in relatively large scaled cluster : • Power control is required • Power consumption increases • All devices in cluster must be in inactive data transmission mode • Using static and mobile nodes in overlapped small scaled sub-clusters : • Sequential positioning is executed in each sub-cluster • Low power consumption • Associated sub-cluster in positioning mode should be in inactive data transmission mode • Case 1 Cluster 1 • Case 2 Cluster 1 K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  17. Positioning Scenario for Star topology • Star topology • PAN coordinator activated mode • Positioning all devices • Re-alignment of positioning FFD’s list is not required • Target device activated mode • Positioning is requested from some device • Re-alignment of positioning FFD’s list is required K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  18. Positioning Scenario for Cluster-tree Topology • Cluster-tree topology K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  19. Octets : 2 1 0/4/8 variable 2 Frame control Sequence number Addressing fields command frame identifier Positioning parameter Command payload FCS MHR MAC payload MFR Modifications of MAC Common Frame • Features • Frame control field • frame type : positioning (new addition) • Command frame identifier field • Positioning request/response (new addition) • Positioning parameter information field • Absolute coordinates of positioning FFDs • POS range • List of positioning FFDs and target devices • Power control • Pre-determined processing time (T) K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  20. Signal Processing for Accuracy Improvement (1) • Technical requirement for positioning • “It can be related to precise (tens of centimeters) localization in some cases, but is generally limited to about one meter” • Parameters for technical requirement • Pulse duration : • Required clock speed High Cost ! • Fast ADC clock speed in the receiver is also required for noncoherent power detection based OOK reception K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

  21. Signal Processing for Accuracy Improvement (2) • Proposed parallel window bank • Fast clock can be implemented by using parallel signal processing windows with low clock speed • : Target clock speed • : Number of signal processing windows • : Window clock speed • Example • Pulse duration is 3.33 nsec • Target speed is 300 MHz • Each signal processing window has 3 MHz speed • Number of windows is 100 Only 3 MHz is required !!! K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon

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