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

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

3. Vinko’s Model Developed in a special committee within IEEE 802.11 HTSG
November 2003
Developed in a special committee within IEEE 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

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

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

6. 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

7. 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

8. Intel Measurements One (typical) office environment
November 2003
Intel Measurements
One (typical) office environment
Distance 5-25 m and RMS delay 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

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

10. 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

11. 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,
Model C
315, 18
305, 23
3.4,
Model D
324, 17
312, 18
3.9, 3.3
Model E
311, 13
299, 24
4.1,
IID Channel
325, 4
Qinghua Li, Intel Corporation

12. 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

13. 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

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

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

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

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

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