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

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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: Recommendations of the Range Issue Subcommittee Date Submitted: September 2004 Source: Frederick Martin, Motorola, Inc., Colin Lanzl, Aware, Inc., Paul Gorday, Motorola, Inc., Rick Roberts, Harris Corporation, Kai Siwiak, TimeDerivative, Inc. Contact: F. Martin, Motorola, Inc., 8000 W. Sunrise Blvd. Plantation, FL 33322 Voice: +1 954-723-6395, FAX: +1 954-723-3712, E-Mail: Re: Range Issue Sub-Committee Abstract: A model and basis of comparison is proposed for comparing range performance of the baseline 802.15.4 PHY layer with proposals for 802.15.4a. Purpose: Tutorial information on capabilities of current 15.4 hardware. 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. Martin et al

  2. Sub-Committee Charter “In response to the 802.15.4a PAR, clause 12, Scope of Proposed Project (document 15-04-0048-01-004a), this subcommittee's scope is to study the range implications of 802.15.4 devices and how we might ask the 802.15.4a proposers to show at least an enhanced range mode.” Martin et al

  3. The issue 802.15.4 bands: 250 kbit/s @ 2400 MHz (worldwide) 40 kbit/s @ 900 MHz (North America) 20 kbit/s @ 868 MHz (Europe) Power: typical 0 dBm maximum: Regulatory max (100 mW Europe, 1 W US !!) Antenna: not specified Receiver sensitivity: not specified Result: typical indoor range may be 10 to 30 m maximum outdoor range may be several km !!! Martin et al

  4. The Search for Guidance (2) 802.15.4 PAR – Purpose [To provide a standard for ultra low complexity, ultra low cost, ultra low power consumption and low data rate wireless connectivity among inexpensive devices. The raw data rate will be high enough (maximum of 200kbs) to satisfy a set of simple needs such as interactive toys, but scaleable down to the needs of sensor and automation needs (10kbps or below) for wireless communications. 802.15.4 PAR -- Scope [This project will define the PHY and MAC specifications for low data rate wireless connectivity with fixed, portable and moving devices with no battery or very limited battery consumption requirements typically operating in the Personal Operating Space (POS) of 10 meters … Martin et al

  5. The Search for Guidance (2) 802.15.4a PAR – Scope [This project will define an alternative PHY clause for a data communication standard with precision ranging, extended range, enhanced robustness and mobility amendment to standard 802.15.4 (18a).] 802.15.4a PAR -- Purpose [To provide a standard for a low complexity, low cost, low power consumption alternate PHY for 802.15.4 (comparable to the goals for 802.15.4). The precision ranging capability will be accurate enough, several centimeters or more, and the range, robustness and mobility improved enough, to satisfy an evolutionary set of industrial and consumer needs for WPAN communications. The project will address the requirements to support sensor, control, logistic and peripheral networks in multiple compliant co-located systems and also coexistence (18b).] Martin et al

  6. The Philosophy behind the Proposed Solution In the spirit of the 802.15.4 PAR, compare 4A proposals with typical low cost, low power 802.15.4a implementations Transmit Power: +6 dBm (900 MHz), 0 dBm (2400 MHz) Receive Sensitivity: -95 dBm (900 MHz), -90 dBm (2400 MHz) isotropic antenna See specs for Freescale MC13192 CompXs – CX1540 Atmel – AT86RF210 Chipcon -- CC2420 Martin et al

  7. Indoor Path Model Comparison Colin Lanzl Kai Siwiak Paul Gorday Martin et al

  8. Two-Breakpoint Model with Recommended Parameters PL(d )= -10log{[c/(4pdfm)]2 [1-exp(-(dt1 /d)g1-2)][1-exp(-(dt2/d)2- 1]}, where: PL: pathloss, dB; d: distance between transmitter and receiver; fm: geometric mean of transmitted frequency band; g1: propagation constant after first breakpoint (3.7); g2: propagation constant after second breakpoint (10.5); c: velocity of propagation; dt1: first breakpoint distance from transmitter (5 meters); dt2: second breakpoint distance from transmitter (30 meters). Martin et al

  9. Loss-per-Meter Indoor Model with Recommended Parameters • PL(d )= -10log{[c/(4pdfm)]2} + *d, • where: • PL: pathloss, dB; • d: distance between transmitter and receiver; • fm: geometric mean of transmitted frequency band; • : loss-per-meter parameter (0.60dB per meter); • c: velocity of propagation. Martin et al

  10. Comparison of Indoor Path Loss Models Martin et al

  11. Path Loss References [1] K. Siwiak, A. Petroff, “A Path Link Model for Ultra Wide Band Pulse Transmissions,” Proc. IEEE Vehicular Techonlogy Conference, Spring 2001, vol. 2, pp. 1173-1175. [2] D. Devasirvatham, et al., “Multi-Frequency Radiowave Propagation Measurements in the Portable Radio Environment,” IEEE International Conference on Communications, April 1990, vol. 4, pp. 1334-1340. [3] K. Marquess, “Physical Model Sub-Group Discussion and Questions,” Submission to IEEE 802.15 Working Group for Wireless Personal Area Networks, Doc. IEEE 802.15/138r0, Nov. 1999. [4] K. Siwiak, “Basic Propagation Attenuation Model Suitable for UWB and Narrow Band Signals,” IEEE P802.15 Working Group for Wireless Personal Area Networks, Doc. IEEE P802.15-04/0408r1, August 2004. [5] D. Cassioli, et al., “The Ultra-Wide Bandwidth Indoor Channel: From Statistical Model to Simulations,” IEEE Journal on Selected Areas in Communications, vol. 20, no. 6, Aug. 2002. [6] S. Ghassemzadeh, et al., “A Statistical Path Loss Model for In-Home UWB Channels,” IEEE Conference on Ultra Wideband Systems and Technologies, May 2002, pp. 59-64. [7] L. Rusch, et al., “Characterization of UWB Propagation from 2 to 8 GHz in a Residential Environment,” Martin et al

  12. Flat Fading Margin for 802.15.4 • Assume that both 802.15.4 PHY’s undergo flat Rayleigh fading • Chip pulse length is relatively long compared to RMS delay spread: (pulse length = 1 s at 2.4 GHz, 3.3 s at 900 MHz, 6.7 s at 868 MHz) • Simple 2.4 GHz PHY implementation (no equalizer or rake) shows multipath performance similar to flat fading for RMS delay spreads up to 300-400 ns (doc. 337r0). 868/915 MHz PHY would tolerate more. • Diversity methods (antenna, rake, mesh network, etc.) would improve performance relative to flat Rayleigh fading, but are not considered here. • Rayleigh fading margin vs. desired reliability • 10 dB margin gives 90% probability of exceeding desired level • 13 dB margin gives 95% probability of exceeding desired level • Typical PHY sensitivity (1% PER, 20-byte PSDU) • 2.4 GHz PHY: -90 dBm • 868/915 MHz PHY: -95 dBm • Typical performance is 3-5 dB better than 802.15.4 PHY spec. Martin et al


  14. Sub-Committee Recommendations • Compare proposals with typical low-cost, low-power implementations of 802.15.4. See slide 6. • 2. Apply either the 2 breakpoint model (slide 8) or the loss per meter model (slide 9) as a basis for comparison. • 3. Adopt 10 dB as the flat fading margin for the 802.15.4 baseline per slide 12. • 4. Leave to proposers the responsibility for specifying and justifying fading margin and receiver performance assumptions for their proposals. Martin et al

  15. Discussion ??? Martin et al