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

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Presentation on Radio Channel Model for Indoor UWB WPAN Environments] Date Submitted: [08 July, 2002] Source: [J. Kunisch, J. Pamp] Company [IMST GmbH] Address [Carl-Friedrich-Gauß-Str. 2, 47475 Kamp-Lintfort, Germany] Voice:[+49 2842 981 454], FAX: [+49 2842 981 499], E-Mail:[kunisch@imst.de] Re: [Call for Contributions on Ultra-wideband Channel Models(02208r1P802-15_SG3a-Call-Contributions-UWB-Channels.doc)17 April, 2002] Abstract: [Presentation of 02281r0P802-15_SG3a-IMST-Response-Call-Contributions-UWB-Channel-Models.doc] Purpose: [For presentation at July 2002 meeting] 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. J. Kunisch, J. Pamp, IMST GmbH

2. Radio Channel Model for Indoor UWB WPAN Environments J. Kunisch, J. Pamp IMST GmbH, Kamp-Lintfort, Germany • Measurements • Model Objectives • Modeling Approach • Results • Summary and Outlook J. Kunisch, J. Pamp, IMST GmbH

3. MeasurementBandwidth FCC 3.1-10.6 GHz (Feb 2002) MEASUREMENTS (2001) MEASUREMENTS 1-11 GHz (2001) 160 ns (48 m) unique excess delay J. Kunisch, J. Pamp, IMST GmbH

4. Measurement Procedure For all Rx positions For all Tx positions • Tx Antenna: • Mounted on positioner • Omni • ~1.5 m height • 150 x 30 (150 x 8) grid positions • Stepsize: 1 cm (x, y) • Rx Antenna: • Mounted on tripod • Omni • ~1.5 m height • Rx positions separated ~ 1-2 m For all Tx grid points Measure S21 Equal  30000 transfer functions • DOA/DOD/SAR analysis atTx position • (n,m)-MIMO analysis(n = 2...3, m >> 1) • … • SETUP J. Kunisch, J. Pamp, IMST GmbH

5. Measurement Environment Office-to-Office (R131-R132) Office (R131) 3 Rx positions increasingly shadowed by metal cabinet 3 Rx-Tx pairs  NLOS, (N)LOS, LOS conditions J. Kunisch, J. Pamp, IMST GmbH

6. Model Objectives Why is there a need for “ultra-wideband” radio channel models? What should an UWB model account for? Example: Minimum bandwidth for two-way echo resolution J. Kunisch, J. Pamp, IMST GmbH

7. Model Objectives Individual echoes Dense multipath exponential decay region Deviation of multipath envelope from exponential decay Average power delay profile for 30 x 30 measured baseband impulse responses on a 30 cm x 30 cm grid (LOS conditions). Bandwidth = 10 GHz. J. Kunisch, J. Pamp, IMST GmbH

8. Model Objectives Individual echoes Trailing multipath behind LOS (regular structure) Wall reflection + trailing multipath LOS Plots: |S21(t, r)| Fading pattern Coherent superposition: dense multipath Measured PDP’s as function of distance (LOS conditions). J. Kunisch, J. Pamp, IMST GmbH

9. Model Objectives Measurement Plots: |S21| Spatial Frequency (l-1) Distance Delay Frequency J. Kunisch, J. Pamp, IMST GmbH

10. Model Objectives R.M.S. average of 10 measured transfer functions (non-LOS conditions). J. Kunisch, J. Pamp, IMST GmbH

11. Model Objectives • Model type: hybrid statistical/quasi-deterministic; “synthetic measurement” • Space-variant complex (baseband) impulse responses / transfer functions • Time-variance by trajectory of receiver • “Simple” • Suited for simulations J. Kunisch, J. Pamp, IMST GmbH

12. Modeling Approach Proposal: • Hybrid modeling Individual echoes:Quasi-deterministicapproach Dense multipath:Statistical approach Each individual echo has an associated multipath cluster J. Kunisch, J. Pamp, IMST GmbH

13. Modeling Approach Generation of individual echoes by virtual sources Points that apparently emit wave fronts impinging at Rx (corresponding to individual echoes) Proposal: • Generate individual echoes by fixed set of virtual sources Rationale: • Introduce coherence if Rx position changes locally J. Kunisch, J. Pamp, IMST GmbH

14. Modeling Approach Definition of virtual source positions by imaging Proposal: • Virtual source position definition by imaging • Only a subset of all images of a Tx in a generic room is used Rationale: • Some strong early echoes indeed correspond geometrically to imaging • Floor reflections • Ceiling reflections • Wall reflections • Captures characteristic dimensions of generic rooms (interarrival times) • Simple and extensible J. Kunisch, J. Pamp, IMST GmbH

15. Modeling Approach 1. Definition of virtual sources Tx Example for set of Rx positions Y1 Y0 X0 X1 Images up to order 3(in x, y, z) Top view J. Kunisch, J. Pamp, IMST GmbH

16. Modeling Approach 1. Definition of virtual sources Positions of potential virtual sources … Image positions Index mapping J. Kunisch, J. Pamp, IMST GmbH

17. Modeling Approach 2. Generation of individual echo parameters Parameter Profile: Office LOS J. Kunisch, J. Pamp, IMST GmbH

18. Modeling Approach 2. Generation of individual echo parameters LOS amplitude: free-space Distance dependent amplitudeof selected individual echoes Parameter Profile: Office LOS Other amplitudes:power law J. Kunisch, J. Pamp, IMST GmbH

19. Modeling Approach 2. Generation of individual echo parameters Distance to k-th individual echo Delay of k-th individual echo Power gain of k-th individual echo direct path other Complex amplitude gain of k-th individual echo J. Kunisch, J. Pamp, IMST GmbH

20. Modeling Approach 3. Generation of associated multipath clusters Proposal: • Cluster amplitudes: Rayleigh distributed • Expectation value ~ exp(-t/g) • Uniform phase • A single cluster realization (per individual echo) for all Rx positions Rationale: • Doppler behavior: Frequency dependent constraint for maximum wavenumber Delayed copies Plot: 20 log10(|S21|); one individual echo + associated multipath cluster J. Kunisch, J. Pamp, IMST GmbH

21. Modeling Approach 3. Generation of associated multipath clusters Multipath power values k-th echo, n-th delay bin wrt cluster start Exponential decay with delay n Drawn from exponential distribution with parameter Complex multipath amplitudes, wrt associated individual echo Phase uniformly distributed J. Kunisch, J. Pamp, IMST GmbH

22. Modeling Approach 4. Superposition of individual echoes and associated multipath clusters Complex amplitude gain of k-th individual echo at -th receiver position Shift multipath cluster to delay of k-th echo at r-th receiver position Basic gain Delay of k-th individual echo • Normalized baseband impulse response for • delay bin n • receiver position r • individual echo k J. Kunisch, J. Pamp, IMST GmbH

23. Modeling Approach 5. Filtering and frequency power decay DFT DFT frequency map Limitation to bandwidth B Frequency dependent power decay J. Kunisch, J. Pamp, IMST GmbH

24. Modeling Approach 6. Observation noise 7. Normalization Discrete Continuous Impulse response Transfer function J. Kunisch, J. Pamp, IMST GmbH

25. Modeling Approach • Hybrid modeling approach: • Individual echoes: quasi-deterministic • Dense multipath: statistical • Individual echoes generated for several receiver positions • Each individual echo: associated with a diffuse multipath cluster • Cluster arrival time: equal to arrival time of associated individual echo • Rayleigh amplitude echoes generated in every bin • Exponential echo power decay law, uniformly distributed phase • Cluster height: set to a certain amount below power of associated individual echo • Decay parameter (unique for all clusters) similar to decay parameter of the overall single cluster • All clusters generated according to the same parameters • Each individual echo: only a single multipath cluster realization generated for all positions J. Kunisch, J. Pamp, IMST GmbH

26. Results Measurement Model Average power delay profile for 30 x 30 baseband impulse responses on a 30 cm x 30 cm grid for LOS conditions. Plots are expected to be “similar”, not identical. J. Kunisch, J. Pamp, IMST GmbH

27. Results Measurement Model Color-coded power delay profiles for 150 baseband impulse responses along 150 cm distance almost perpendicular to the Rx-Tx line-of-sight. Plots are expected to be “similar”, not identical. Plots: 20 log10(|S21(t, r)|) J. Kunisch, J. Pamp, IMST GmbH

28. Results Measurement Plots: |S21| Spatial Frequency (l-1) Distance Delay Frequency J. Kunisch, J. Pamp, IMST GmbH

29. Results Model Plots: |S21| Spatial Frequency (l-1) Distance Delay Frequency J. Kunisch, J. Pamp, IMST GmbH

30. Results Measurement Model Example for a single impulse response. A Kaiser-Bessel frequency domain window has been applied. Plots are expected to be “similar”, not identical. J. Kunisch, J. Pamp, IMST GmbH

31. Results Measurement Model Example for a single impulse response (detail). A Kaiser-Bessel frequency domain window has been applied. Plots are expected to be “similar”, not identical. J. Kunisch, J. Pamp, IMST GmbH

32. Summary and Outlook Hybrid modeling approach • Individual echoes: quasi-deterministic • Dense multipath: statistical Measurement based General and extensible, e.g. • Virtual sources: more sophisticated algorithms possible. • Various criteria for individual echo selection e.g. • minimum/maximum distance, mirroring order, angle-of-arrival masks, radiation pattern weighting, …. • Selection of individual echo power • radiation pattern weighting, … • Time variance: movement of virtual sources. • MIMO analysis(yet to be verified based on already available measurement data) J. Kunisch, J. Pamp, IMST GmbH