Doc.: IEEE htsg Submission July 2003 MetalinkSlide 1 Time Variable HT MIMO Channel Measurements Nir Tal Metalink

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 2 Purpose Provide a snapshot of real-environment MIMO measurements with time variability Derive HT capacity figures and quantify improvement Quantify time variability and underlying effects

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 3 Measurement Information Several hundred of measurements taken at various locations and scenartios 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 moves between measurement positions

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 4 Measurement Set Up Philosophy: –Full simultaneous 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

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 5 Set-Up Block Diagram

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 6 Signal Transmission Setup

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 7 Transmission Antennas

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 8 Reception Antennas

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 9 Spectrum Analyzer/ Down Converter Setup

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 10 Sampling Setup

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 11 Indoor Measurement Locations

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 12 Result Snapshot

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 13 Intra-Room (NLOS), Typical Channel (M11-11)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 14 Impulse Response (M11-11)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 15 Time Frequency Response (M11-11)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 16 Frequency Response Time Variability (M11-11)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 17 RMS Delay Spread (M11-15)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 18 MIMO Capacity (theoretical) The theoretical MIMO channel capacity is given by [1]: Where: C – Capacity [bps/Hz], W- Bandwidth [Hz], P- Power [W], - Noise Variance [W], H- Channel Matrix, - TX Antenna Number

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 19 Real-Environment Calculated Capacity (M11-14) (MIMO Capacity)/2

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 20 Statistical Findings

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 21 MIMO Capacity Enhancement- NLOS, Dist= 25.6m (M11-XX)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 22 MIMO Capacity Enhancement- LOS, Dist=25m (M11-XX)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 23 Periodic Modulation In nearly all tests, a strong AM-like periodicity is clearly seen. The period of this modulation was tested to be exactly 100Hz

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 24 Fluorescent Effect Setup

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 25 Fluorescent Effect Setup (cont.)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 26 Fluorescent Effect Setup (cont.)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 27 Spectrum at the Various Scenarios

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 28 Time Domain Power Plot of Fluorescent Effect

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 29 The Fluorescent Effect Fluorescent lights become conductive twice every AC power cycle. During that period, the electromagnetic environment (reflections) are changed. The channels in such environment exhibit strong AM modulation in all parameters (frequency response, RMS delay spread, capacity, etc.) We therefore suggest to incorporate this effect into the MIMO channel models as it is one of the major causes of channel time variability

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 30 Conclusions In typical enterprise scenario 2 antenna MIMO enhances the median capacity by 1.5-2x (NLOS and LOS) Channels exhibits “slow” variability changes over 100ms (f<10Hz) In the vicinity of fluorescence lights the channel is modulated by a strong 100/120Hz AM modulation (up to 5dB)

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 31 Summary A snap-shot of channel measurements in office environment has been presented Measurements are ongoing and their study shall include topics such as: antenna polarization, channel reciprocity and LOS behavior. These results are being integrated into the Channel Modeling Sub-Committee led by Erceg.

Doc.: IEEE htsg Submission July 2003 MetalinkSlide 32 References [1] – Branka Vucetic, “Space-Time Coding”, Wiley& Sons, 2003