1. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 1 Project: IEEE 802.15 Study Group for Wireless Personal Area Networks (WPANs) Submission Title: [Ultra-Wideband Channel Model for Farm/Open-Area Applications] Date Submitted: [11 May, 2004] Source: [Shahriar Emami, Celestino A. Corral, Gregg Rasor]: Company1 [Freescale Semiconductor], Address [8000 W. Sunrise Blvd., Plantation, FL 33322], Voice:[(954) 723-3854], FAX: [(954) 723-3883] Re: [Channel Model Submission] Abstract:[An ultra-wideband channel model for open area/farm applications is submitted. The channel model is based on ray tracing that captures signal descriptors including frequencies. The rationale behind the channel model is developed and presented in support of the presentation.] Purpose:[An understanding of the open area outdoor environment for ultra-wideband (UWB) signal coverage is needed for 802.15 TG4a. This channel model should assist in predicting UWB range and proper signal design for open area applications.] 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. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 2 Ultra-Wideband Channel Model for Farm/Open-Area Applications Understanding UWB Propagation in Open Areas Subject to Selected Environmental Factors The presenters wish to acknowledge the support and contributions of: Glafkos Stratis/Motorola Salvador Sibecas/Motorola Shahriar Emami, Celestino A. Corral, Gregg Rasor Freescale Semiconductor

3. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 3 Outline Ultra-wideband Outdoor Channel Model Status Special Considerations –Approach –Frequency Selection –Simulation Setup Simulation Results –Ground conditions –Channel Impulse Response and Ray Statistics –Coverage Summary and Conclusions Proposed Continuing Investigations

4. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 4 Channel Model Status Prior Efforts: –Two-ray UWB path loss model: S. Sato and T. Kobayashi, “Path-loss exponents of ultra wideband signals in line-of-sight environments,” IEEE802.15-04-0111-00-004a, March 2004. –Deterministic UWB channel model based on ray tracing approach: B. Uguen, E. Plouhinec, Y. Lostanlen, and G. Chassay, “A deterministic ultra wideband channel modeling,” 2002 IEEE Conf. Ultra Wideband Syst. Tech. We shall show this in simulation We use approach considered here

5. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 5 Special Considerations Farm areas feature isolated clusters of scatterers Material properties may change with frequency. (For our simulations, we assume material properties constant over frequency.) In addition, the outdoor channel is subject to environmental changes –Seasonal changes (snow, ice, etc. in some regions) –Rain/wet conditions

6. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 6 Different Absorption Regions -6-4-2024681012141618 Conduction Space Charge Polarization Dipole and Ionic Relaxation AtomicElectronic Absorption 60Hz Frequency Range Of Interest Dielectric practically constant over frequency range of interest. Log frequency (Hz) R. C. Dorf (Ed.), The Electrical Engineering Handbook, 2 nd Ed., Boca Raton, Florida: CRC Press, 1997. We assume no dielectric changes over frequency

7. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 7 Approach Use deterministic 3-D ray tracing simulator - Employs –geometric optics –uniform theory of diffraction (UTD) –Generates Received signal strength Ray statistics (path length/delay) Signal descriptors include frequency, polarization, etc. UWB channel sounding is achieved by superposition of NB channel sounding - Conventional channel sounding - FCC emissions mask scaled channel sounding M. F. Iskander and Z. Yun, “Propagation prediction models for wireless communication systems,” IEEE Trans. Microwave Theory Tech., vol. 50, pp. 662—673, March 2002.

8. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 8 Frequency Selection Channel Sounding“High-Pass” Sounding 0 dBm -14.8 -13.8 -12.8 -11.4 -11.2 “Band-Pass” Sounding -14.8 -13.8 -12.8 -11.4 -11.2 Energy of band concentrated in high band frequency Energy of band concentrated in geometric center frequency 3.104.245.346.728.6410.63.104.245.346.728.6410.6 3.624.765.997.629.57

9. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 9 Simulation Set-Up 3-D omni antenna pattern used Omni pattern assumed at all frequencies Provides worst-case delay modeling Farm area consists of two-story wood home and metal grain silo. Ground is not flat; has slight variations in height. omni antenna above house omni antenna near ground Receiver grid placed around home, 200m X 200m Receiver spacing was 4m X 4m Receiver height was at 1.3m For omni antenna above house, antenna was at 12.5m height For omni antenna near ground, antenna was at 1.5m height.

10. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 10 Coverage Results Lowest Frequency – 4.24 GHz 200 m Highest level -64.4 dBm Shadowing due to metal silo evident Ripple due to two-ray phenomenon evident Dry soilWet soil and wet roof Highest level -66.5 dBm Smoother ripple closer to antenna Impact of roof more significant TX power = 0 dBm

11. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 11 Coverage Results Full Frequencies -- Channel Sounding Dry soil Highest level -64.4 dBm Some deep fades are eliminated, others softened Ripple due to two-ray phenomenon still evident, although smooth ripple closer Highest level -66.5 dBm Higher signals closer to antenna Shadowing due to silo and roof still significant Wet soil TX power = 0 dBm Dry/wet conditions are fairly similar

12. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 12 Coverage “High-pass” and “Band-pass” Sounding Dry soil High-pass sounding Highest level -61.8 dBm Significant shading by house as well as silo Dry soil Band-pass sounding Highest level -60.2 dBm Range for -75 dBm sensitivity is quite low, on the order of 15 m. High-pass and band- pass sounding are similar TX antenna placed at 1.5m height and at the side of the house

13. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 13 Simulation--Validation Powers in the different frequency bands are summed together Received power profile in agreement with the work of Sato and Kobayashi TX antenna placed at 1.5m height and at the side of the house

14. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 14 Simulation Results—Ground Conditions Ground conditions (wet or dry) has almost no impact on received signal power or delay spread. Subsequent simulations were assuming dry conditions

15. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 15 Simulation Results— Channel Impulse Response CIR is similar to two-ray model.

16. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 16 Simulation Results— Channel RF Parameters Scenario A Scenario B Received Power (dBm) -83 -74 Scenario A Scenario B Mean Excess Delay (ns) 380 365 RMS Delay (ns) 19 26 - Scenario A: transmit antenna is placed on the top of farm house - Scenario B: transmit antenna is placed along the side of the house Table I. 90 percentile received powerTable II. 90 percentile delay spread

17. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 17 Simulation Results—Ray Statistics Statistics of the two rays are found to be Rayleigh distributed.

18. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 18 Simulation Results—Channel Sounding Channel (uniform) sounding leads to larger received power as compared to constrained channel (FCC-mask compliant) sounding. Over 10dB difference FCC-mask complaint Uniform sounding

19. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 19 Simulation Results— “High-pass” or “Band-pass” Sounding “Band-pass” sounding results in +1 dB higher received power compared to “high- pass” sounding. High-pass and band- pass sounding are similar High-pass Band-pass

20. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 20 Simulation Results—Coverage 100x100 30x30 Coverage (%) 85 Table III. % grid Coverage, if the receiver sensitivity is -90 dBm.

21. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 21 Simulation Results—Channel Model CM1*CM2*CM3* I mean1.4092e-007 3.1052e-008 -5.8368e-009 Q mean-1.8287e-008 5.9910e-009 -4.2345e-009 MED (ns) 22.654 35.491 251.53 RMS Delay (ns) 20 3.5565 5.0733 * The transmitter receiver separation distances are 5, 15 and 75 meters in CM1, CM2 and CM3, respectively.

22. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 22 Summary and Conclusions UWB Ray Tracing: Ray tracing with realistic antennas and appropriate material properties was implemented. Analyses included all ray statistics/parameters (ray physics). CIR of UWB channel is found by superposition of CIR of individual bands with appropriate power weighting. Channel Modeling Results: 5-band approach is adequate for predicting outdoor coverage in farm scenario as verified by prior two-ray modeling. “High-pass” sounding yields most conservative results. RF parameters appear almost insensitive to ground material/conditions. 100m range achievable with -90dBm RX sensitivity. CIR is similar to that of two-ray model. RMS delay depends on location of antenna and statistics of the rays. Two-ray statistics are verified to have Rayleigh distribution.

23. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 23 Ongoing Investigations Incorporate uplink simulations. Alternative frequency domain based approach. Measurement and verification.

24. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 24 Back-up Slides

25. doc.: IEEE 802.15-04-0215-00-004a Contribution May 7, 2004 Shahriar Emami, Freescale SemiconductorSlide 25 Material Properties Pellat-Debye Equations for loss at single relaxation time. Real permittivity exhibits low- pass frequency response. Imaginary part exhibits band- pass response. Regions can be separated for different relaxation times. Temperature effects are not modeled, but only affected by change in density of dielectric material. Reference Data for Engineers: Radio, Electronics, Computer & Communications, 8 th Ed., Carmel, Indiana: SAMS, Prentice-Hall Computer Pub., 1993.