1. Month 2002
doc.: IEEE /xxxr0
Nov 2003
MIMO Channel Measurements Using Super-Resolution Techniques Nir Tal, Amir Leshem, Eran Gerson Lior Kravitz, Guy Shochet, Metalink Broadband
Metalink
John Doe, His Company

2. Month 2002
doc.: IEEE /xxxr0
Nov 2003
Purpose
Present new results stemming from Super-Resolution (SR) analysis of a set of indoor-measurements.
Provide validation information to the suggested channel model ( /871r0 )
Present statistics of measured results on Fluorescence modulation and RMS delay spread.
Metalink
John Doe, His Company

3. Measurement Information
Month 2002
doc.: IEEE /xxxr0
Nov 2003
Measurement Information
About 500,000 measurements taken at various locations and scenarios within the company.
Measurements were taken at the lower UNII band (~5.2 GHz)
Receive antennas fixed at a height of ~2m (e.g. AP position)
TX setup is mobile between measurement locations
Antenna spacing used was ~/2 spacing (2.5-3 cm)
Metalink
John Doe, His Company

4. Measurement Set Up Philosophy: Full simultaneous 2x2 MIMO measurements
Month 2002
doc.: IEEE /xxxr0
Nov 2003
Measurement Set Up
Philosophy:
Full simultaneous 2x2 MIMO measurements
Relatively slow sampling rate (46MHz)– long sampling period (100msec)
Store all samples and post-process offline
Use wideband transmission signals (~20MHz)
Omni reception and transmission antennas
Metalink
John Doe, His Company

5. Nov 2003
Set-Up Block Diagram
Metalink

6. Signal Transmission Setup
Nov 2003
Signal Transmission Setup
Metalink

7. Signal Reception Setup
Nov 2003
Signal Reception Setup
Metalink

8. Nov 2003
Sampling Setup
Metalink

9. Indoor Measurement Locations
Nov 2003
Indoor Measurement Locations 1 2 3 4 5 6 7 8 9 10 11 12 24 23 20 21
36 Meters
RX antennas
Metalink

10. The Need for Super Resolution
Nov 2003
The Need for Super Resolution
Direct measurement of individual channel tap time variation requires a fast sampling frequency (>500MHz) over relatively long durations (~100ms)
Impractical due to memory constraints
Metalink

11. The Need for Super Resolution (cont.)
Nov 2003
The Need for Super Resolution (cont.)
Our measurement system favors long sampling periods (~100ms) over a fast sampling rate (~40MHz)
Tap statistics and time variation can be extracted using super-resolution techniques.
Metalink

12. Nov 2003
The ESPRIT Technique
After [1], Assuming that the channel can be modeled as a set constant offset non-stationary impulses:
Metalink

13. The ESPRIT Technique (cont.)
Nov 2003
The ESPRIT Technique (cont.)
Its frequency response can is:
We can therefore rewrite the channel model as a set of linear equations
Metalink

14. The ESPRIT Technique (cont.)
Nov 2003
The ESPRIT Technique (cont.)
Where:
Metalink

15. The ESPRIT Technique (cont.)
Nov 2003
The ESPRIT Technique (cont.)
And N being a Gaussian noise matrix with covariance
Using the ESPRIT technique we can estimate a set of delays and the amplitude matrix A.
Metalink

16. Model Order A unique solution exists as long as
Nov 2003
Model Order
A unique solution exists as long as
The model order (number of taps) can be deduced using a variety of techniques (e.g. MDL)
In our analysis we use SVD analysis (rank) of H as an indicator of the “correct” model order
Metalink

17. Measurement and Analysis Process
Nov 2003
Measurement and Analysis Process
Metalink

18. Nov 2003
Result Snapshot
Metalink

19. Typical Channel Impulse Response Measurement
Nov 2003
Typical Channel Impulse Response Measurement
RX Ant#1
RX Ant#2
TX Ant#1
TX Ant#2
Metalink

20. SVD Structure of the H Matrix
Nov 2003
SVD Structure of the H Matrix
RX Ant#1
RX Ant#2
TX Ant#1
TX Ant#2
Metalink

21. Tap Power Variation (P8)
Nov 2003
Tap Power Variation (P8)
RX Ant#1
RX Ant#2
TX Ant#1
TX Ant#2
Metalink

22. Tap Power Variation Along a 100ms Slice (P8)
Nov 2003
Tap Power Variation Along a 100ms Slice (P8)
RX Ant#1
RX Ant#2
TX Ant#1
TX Ant#2
Metalink

23. Model Clustering Approach [2]
Nov 2003
Model Clustering Approach [2]
Metalink

24. Clustering for TX=1, RX=1 (P8)
Nov 2003
Clustering for TX=1, RX=1 (P8)
Cluster #1
Cluster #2
Metalink

25. Accumulated Reflection Power Variation (P8)
Nov 2003
Accumulated Reflection Power Variation (P8)
RX Ant#1
RX Ant#2
TX Ant#1
TX Ant#2
Metalink

26. Interpolated Reconstructed Frequency Response Generation
Nov 2003
Interpolated Reconstructed Frequency Response Generation
Taking the discrete to continuous inverse Fourier transform of the ESPRIT model parameters yields a frequency response pattern at an arbitrary frequency abscissa.
Metalink

27. Frequency Response (P11)
Nov 2003
Frequency Response (P11)
RX Ant#1
RX Ant#2
TX Ant#1
TX Ant#2
Metalink

28. Nov 2003
Doppler Spectrum
By taking the row-wise FFT of the amplitude matrix (A), we can obtain the Doppler spectrum of each individual reflection
Metalink

29. Reflection Doppler Spectrum
Nov 2003
Reflection Doppler Spectrum
Metalink

30. Cumulative Doppler Spectrum Power
Nov 2003
Cumulative Doppler Spectrum Power
Metalink

31. Nov 2003
Statistical Findings
Metalink

32. Average Doppler spectrum
Nov 2003
Average Doppler spectrum
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33. Average Doppler spectrum
Nov 2003
Average Doppler spectrum
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34. Measured Fluorescent C/I CDF
Nov 2003
Measured Fluorescent C/I CDF
Metalink

35. C/I Distribution on Channel Model [2], [3]
Nov 2003
C/I Distribution on Channel Model [2], [3]
Metalink

36. RMS Delay Spread vs. Distance
Nov 2003
RMS Delay Spread vs. Distance
Metalink

37. Nov 2003
Conclusions
Results show good correlation with suggested channel model [2].
Clustering
Typically 2-3 exponentially decaying clusters are measured.
Doppler spectrum
Measured -10dBc point at ~9Hz, Modeled –10dBc at 6Hz.
Fluorescent effect modeling
Tap modulation is measured on some taps
Measured C/I is ~3dB higher than suggested model
Metalink

38. Conclusions RMS delay spread
Nov 2003
Conclusions
RMS delay spread
Measured RMS delay spreads (60-90ns) consistent with models D and E.
Metalink

39. Month 2002
doc.: IEEE /xxxr0
Nov 2003
References
[1] – R.Roy, A. Paulraj and T. Kailath, “ESPRIT – A subspace rotation approach to estimation of parameters of cisoids in noise,” IEEE Trans. On Acoust., Speech, Signal Processing, 34(4): , October 1986
[2] – Erceg, et al., “Indoor MIMO WLAN Channel Models,“ IEEE /871r0
[3] – Tal, et al., “Fluorescent Light-Bulb Interaction with Electromagnetic Signals “, IEEE n, September 2003.
Metalink
John Doe, His Company