Month 2002 doc.: IEEE 802.11-02/xxxr0 Nov 2003 MIMO Channel Measurements Using Super-Resolution Techniques Nir Tal, Amir Leshem, Eran Gerson Lior Kravitz, Guy Shochet, Metalink Broadband (nirt@metalink.co.il) Metalink John Doe, His Company

Month 2002 doc.: IEEE 802.11-02/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 (802.11-03/871r0 ) Present statistics of measured results on Fluorescence modulation and RMS delay spread. Metalink John Doe, His Company

Measurement Information Month 2002 doc.: IEEE 802.11-02/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

Measurement Set Up Philosophy: Full simultaneous 2x2 MIMO measurements Month 2002 doc.: IEEE 802.11-02/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

Nov 2003 Set-Up Block Diagram Metalink

Signal Transmission Setup Nov 2003 Signal Transmission Setup Metalink

Signal Reception Setup Nov 2003 Signal Reception Setup Metalink

Nov 2003 Sampling Setup Metalink

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

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

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

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

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

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

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

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

Measurement and Analysis Process Nov 2003 Measurement and Analysis Process Metalink

Nov 2003 Result Snapshot Metalink

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

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

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

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

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

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

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

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

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

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

Reflection Doppler Spectrum Nov 2003 Reflection Doppler Spectrum Metalink

Cumulative Doppler Spectrum Power Nov 2003 Cumulative Doppler Spectrum Power Metalink

Nov 2003 Statistical Findings Metalink

Average Doppler spectrum Nov 2003 Average Doppler spectrum Metalink

Average Doppler spectrum Nov 2003 Average Doppler spectrum Metalink

Measured Fluorescent C/I CDF Nov 2003 Measured Fluorescent C/I CDF Metalink

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

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

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

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

Month 2002 doc.: IEEE 802.11-02/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):1340-1342, October 1986 [2] – Erceg, et al., “Indoor MIMO WLAN Channel Models,“ IEEE 802.11-03/871r0 [3] – Tal, et al., “Fluorescent Light-Bulb Interaction with Electromagnetic Signals “, IEEE 11-03-0718-04-000n, September 2003. Metalink John Doe, His Company