Validation of 802.11n Channel Models November 2003 Validation of 802.11n Channel Models Qinghua Li Communications Technology Lab Intel Corporation November 2003 Qinghua Li, Intel Corporation

Outline Overview of 802.11n Channel Model November 2003 Outline Overview of 802.11n Channel Model Overview of Intel’s measurements RMS delay spread Capacity comparison Conclusion Qinghua Li, Intel Corporation

Vinko’s Model Developed in a special committee within IEEE 802.11 HTSG November 2003 Developed in a special committee within IEEE 802.11 HTSG Extended from Medbo’s SISO models for HIPERLAN/2 Three companies are doing validation [1—3]. Medbo’s SISO model Angular power delay profile for all taps Correlation matrixes seen from Rx and Tx for each tap Correlation matrix for channel matrix entries and for each tap Generate channel matrix from i.i.d. Gaussian random variables for each tap Cluster decomposition and angle assignment Integration over all angles for each tap Cholesky decomposition Kronecker product of Rx and Tx correlation matrixes Qinghua Li, Intel Corporation

Multipath profile seen from receiver November 2003 Qinghua Li, Intel Corporation

Multipath profile seen from transmitter November 2003 Qinghua Li, Intel Corporation

Correlation matrix on transmit (receive) side November 2003 Correlation matrix on transmit (receive) side 4x4 MIMO channel transmit and receive correlation matrices are Correlation matrix of channel matrix entries and its approximation where h = vec[ H ] Qinghua Li, Intel Corporation

Channel Matrix for Each Tap November 2003 Channel Matrix for Each Tap Channel matrix H for one tap It can be shown that The model delivers time domain channel impulse response for each Tx/Rx antenna pair. Qinghua Li, Intel Corporation

Intel Measurements One (typical) office environment November 2003 Intel Measurements One (typical) office environment Distance 5-25 m and RMS delay 23-79 ns Two 4-by-4 grids of positions are on both Tx and Rx The transmit/receive antenna steps through 16 positions. Channels in 5.15—5.4 GHz band are captured. Qinghua Li, Intel Corporation

Measurement Locations November 2003 Measurement Locations 3m 25m 18m 12m 5m 7m 9m 14m 13m Qinghua Li, Intel Corporation

Pair measurement and model by delay spread November 2003 Pair measurement and model by delay spread Mean and standard deviation of RMS delay spreads in measurements RMS delay spreads in Vinko’s models Model B: 15 ns residential S16 Model C: 30 ns small office S15, S17 Model D: 50 ns typical office S6 Model E: 100 ns large office S9 S6—seq. 15 S7—seq. 19 S8—seq. 20 S9—seq. 21 S10—seq. 22 S15—seq. 29 S16—seq. 30 S17—seq. 31 S18—seq. 32 Mean of τrms (ns) 56.5 68.2 63.4 79.2 67.3 27.4 23.6 34.1 38.5 STD of τrms (ns) 5.6 6.2 6.4 9.1 8.0 4.9 5.5 6.1 Qinghua Li, Intel Corporation

Compare capacity of for 4x4 channels November 2003 Compare capacity of for 4x4 channels 4x4 channel with 20 MHz bandwidth and 4’’ spacing Capacity mean and standard deviation at SNR 15dB Model error is less than 9% Model Capacity (mbps) Measured Capacity (mbps) Relative Error (%) Model B Mean, STD 256, 17 281, 21 8.8, 17.8 Model C 315, 18 305, 23 3.4, 23.4 Model D 324, 17 312, 18 3.9, 3.3 Model E 311, 13 299, 24 4.1, 46.8 IID Channel 325, 4 Qinghua Li, Intel Corporation

Compare 1x1 and 4x4 channel capacity November 2003 Compare 1x1 and 4x4 channel capacity 1x1 and 4x4 measured channels with 20 MHz bandwidth Capacity mean at SNR 15dB MIMO factor is about 3.5 for model C, D, E and their corresponding measurements 1x1 Capacity (mbps) measured, model 4x4 Capacity (mbps) 4x4 Cap. / 1x1 Cap. Model B 89, 95 281, 256 3.1, 2.7 Model C 87, 88 305, 315 3.5, 3.6 Model D 87, 86 312, 324 3.6, 3.7 Model E 86, 87 299, 311 IID Channel Model 87 325 3.7 Qinghua Li, Intel Corporation

Conclusion Three office models (C,D,E) match measurements. November 2003 Conclusion Three office models (C,D,E) match measurements. The residential model (B) doesn’t match measurement well. 4x4 capacity is more than 3.5 times of 1x1’s for model C, D, E and their corresponding measurements The capacity means of model C,D,E are greater than the measured by about 4%. STDs of all models are about 20% smaller than the measured. Means for measured channels are less than that of IID channel by less than 8%. Model E (large office) has smaller capacity means than model D (typical office). Qinghua Li, Intel Corporation

November 2003 References [1] V. Erceg, et al, “Indoor MIMO WLAN Channel Models,” IEEE Doc. No. 802.11-03/161r2, Sept. 2003. [2] N. Tal, “Time Variable HT MIMO Channel Measurements,” IEEE 802.11-03/515r0, July 2003. [3] A. Jagannatham, V. Erceg, “Indoor MIMO Wireless Channel Measurements and Modeling at 5.25 GHz,” Document in preparation, Sept. 2003. Qinghua Li, Intel Corporation

Backup CDF of 1x1 and 4x4 channel capacity for model B. November 2003 Qinghua Li, Intel Corporation

Backup CDF of 1x1 and 4x4 channel capacity for model C. November 2003 Qinghua Li, Intel Corporation

Backup CDF of 1x1 and 4x4 channel capacity for model D. November 2003 Qinghua Li, Intel Corporation

Backup CDF of 1x1 and 4x4 channel capacity for model E. November 2003 Qinghua Li, Intel Corporation