Modeling Environmental Effects on Directionality in Wireless Networks

Transcription

1 Modeling Environmental Effects on Directionality in Wireless Networks Eric Anderson, Caleb Phillips, Douglas Sicker, and Dirk Grunwald University of Colorado Department of Computer Science 26 June 2009 Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 1 / 22

2 Outline 1 Radio Propagation Environments and Directional Antennas Pretty Pictures Measuring Effective Directionality Accuracy of Current Models 2 Estimating Radio Propagation Ray Tracing Propagation Models Directivity Models 3 Directivity and Propagation are not Orthogonal What s Missing? 4 Modeling Fitting Specific Environments Fitting Types of Environments Relating Signals to Environment Parameters Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 2 / 22

3 RF Propagation Environments Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 3 / 22

4 RF Propagation Environments Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 3 / 22

5 Measurement Processes [1/2] Baseline Measurements Calibration and test quality equipment (Agilent E4438C, 89600S VSG and VSA) used for: Reference pattern Calibrating laptop measurements. Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 4 / 22

6 Measurement Processes [2/2] Linear fit for RSS Error Laptop Measurements Dell laptops Atheros AR5213 radios Used for non-reference measurements. Rx dbm Tx dbm Linear fit, slope 0.95 Adjusted R 2 = Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 5 / 22

7 How Bad is it? Patch Panel Antenna db Relative to Peak Mean Patch Outdoor B Patch Outdoor A Patch Indoor A Reference Angle, Degrees Counterclockwise Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 6 / 22

8 How Bad is it? Patch Panel Antenna db Relative to Peak Mean db Patch Outdoor B Patch Outdoor A Patch Indoor A Reference Angle, Degrees Counterclockwise Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 6 / 22

9 How Bad Is It? 24dBi Parabolic Dish, Indoors db Relative to Peak Mean db Parabolic Indoor C Parabolic Indoor B Parabolic Indoor A Reference Angle, Degrees Counterclockwise Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 7 / 22

10 Outline 1 Radio Propagation Environments and Directional Antennas Pretty Pictures Measuring Effective Directionality Accuracy of Current Models 2 Estimating Radio Propagation Ray Tracing Propagation Models Directivity Models 3 Directivity and Propagation are not Orthogonal What s Missing? 4 Modeling Fitting Specific Environments Fitting Types of Environments Relating Signals to Environment Parameters Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 8 / 22

11 Radio Ray Tracing ( P rx = P tx fa (θ 1 )f b (θ 2 )d1 2 ) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 9 / 22

12 Radio Ray Tracing P rx = P tx ( fa (θ 1 )f b (θ 2 )d f a (θ 3 )f b (θ 4 )d 2 2 A 2) two-ray Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 9 / 22

13 Radio Ray Tracing ( P rx = P tx fa (θ 1 )f b (θ 2 )d1 2 + f a (θ 3 )f b (θ 4 )d2 2 A 2 + f a (θ 5 )f b (θ 6 )d3 2 A ) 3 Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 9 / 22

14 Radio Ray Tracing P rx = P tx ( fa (θ 1 )f b (θ 2 )d f a (θ 3 )f b (θ 4 )d 2 2 A 2 + f a (θ 5 )f b (θ 6 )d 2 3 A 3 ) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee 09 9 / 22

15 Path Loss Path loss: Macro-scale function of position & terrain. e.g. Free space, two-ray, HATA/COST231, ITU238,... Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

16 Fading Frequency Time [Credit: Public domain image from Wikimedia commons] Fading: Micro-scale function of many positions and velocities. Treated as function of time. e.g. Rayleigh, Rician, Weibull,... Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

17 Directivity Current Models Fading & path loss Node a gain Node b gain P rx = P tx X f a (θ 1 ) f b (θ 2 ) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

18 Directivity Current Models Fading & path loss Node a gain Node b gain P rx = P tx X f a (θ 1 ) f b (θ 2 ) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

19 Directivity Current Models Fading & path loss Node a gain Node b gain P rx = P tx X f a (θ 1 ) f b (θ 2 ) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

20 Directivity Current Models Fading & path loss Node a gain Node b gain P rx = P tx X f a (θ 1 ) f b (θ 2 ) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

21 Outline 1 Radio Propagation Environments and Directional Antennas Pretty Pictures Measuring Effective Directionality Accuracy of Current Models 2 Estimating Radio Propagation Ray Tracing Propagation Models Directivity Models 3 Directivity and Propagation are not Orthogonal What s Missing? 4 Modeling Fitting Specific Environments Fitting Types of Environments Relating Signals to Environment Parameters Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

22 Directivity What s Missing? Some f(position) Some f(time) }{{} + P rx = P tx X f a (θ 1 ) f b (θ 2 ) Frequency Time + vs. f a (θ 1 ) f b (θ 2 ) d P rx = P tx f a (θ 3 ) f b (θ 4 ) d 2 2 A 2 + f a (θ 5 ) f b (θ 6 ) d3 2 A 3 + =? Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

23 Directivity What s Missing? Some f(position) Some f(time) }{{} + P rx = P tx X f a (θ 1 ) f b (θ 2 ) Frequency Time + vs. f a (θ 1 ) f b (θ 2 ) d P rx = P tx f a (θ 3 ) f b (θ 4 ) d 2 2 A 2 + f a (θ 5 ) f b (θ 6 ) d3 2 A 3 + =? Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

24 Directivity What s Missing? Some f(position) Some f(time) }{{} + P rx = P tx X f a (θ 1 ) f b (θ 2 ) Frequency Time + vs. f a (θ 1 ) f b (θ 2 ) d P rx = P tx f a (θ 3 ) f b (θ 4 ) d 2 2 A 2 + f a (θ 5 ) f b (θ 6 ) d3 2 A 3 + =? Antenna gain in off directions is ignored! Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

25 An Obvious Problem Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

26 An Obvious Problem f a (θ 1 ) f b (θ 2 ) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

27 An Obvious Problem f a (θ 3 ) f b (θ 4 ) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

28 An Obvious Problem Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

29 Outline 1 Radio Propagation Environments and Directional Antennas Pretty Pictures Measuring Effective Directionality Accuracy of Current Models 2 Estimating Radio Propagation Ray Tracing Propagation Models Directivity Models 3 Directivity and Propagation are not Orthogonal What s Missing? 4 Modeling Fitting Specific Environments Fitting Types of Environments Relating Signals to Environment Parameters Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

30 Environment Fitting Patch Panel Antenna db Relative to Peak Mean Normalized Gain, db Patch Outdoor B Patch Outdoor A Patch Indoor A Reference Angle, Degrees Counterclockwise Orthogonal Model Error Azimuth Angle Environment = Error Error is correlated with angle Fit existing model error Bin by angle Find regression fit Characterizes specific link, antenna, environment. Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

31 Environment Fitting Patch Panel Antenna db Relative to Peak Mean Normalized Gain, db Patch Outdoor B Patch Outdoor A Patch Indoor A Reference Angle, Degrees Counterclockwise Orthogonal Model Error Azimuth Angle Environment = Error Error is correlated with angle Fit existing model error Bin by angle Find regression fit Characterizes specific link, antenna, environment. Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

32 Environment Fitting Patch Panel Antenna db Relative to Peak Mean Normalized Gain, db Patch Outdoor B Patch Outdoor A Patch Indoor A Reference Angle, Degrees Counterclockwise Orthogonal Model Error Azimuth Angle Environment = Error Error is correlated with angle Fit existing model error Bin by angle Find regression fit Characterizes specific link, antenna, environment. Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

33 Environment Fitting Patch Panel Antenna db Relative to Peak Mean Normalized Gain, db Patch Outdoor B Patch Outdoor A Patch Indoor A Reference Angle, Degrees Counterclockwise Orthogonal Model Error Azimuth Angle Environment = Error Error is correlated with angle Fit existing model error Bin by angle Find regression fit Characterizes specific link, antenna, environment. Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

34 Error Comparison Orthogonal Model Error Normalized Gain, db Azimuth Angle Residual Error After Offset Fitting Error in db Azimuth Angle Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

35 Patch Outdoor B Patch Outdoor A Patch Indoor A Reference Types of Environments Environment = set of offsets db Relative to Peak Mean Normalized Gain, db Patch Panel Antenna Angle, Degrees Counterclockwise Orthogonal Model Error Azimuth Angle Group of environments = distribution of offsets Offset ANOVA Variation is predicted by: Type of environment Antenna gain f (θ k ) Observation point (negligible) 0 e.g. {-1,-2,-5,-2, } Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

36 Patch Outdoor B Patch Outdoor A Patch Indoor A Reference Types of Environments Environment = set of offsets db Relative to Peak Mean Normalized Gain, db Patch Panel Antenna Angle, Degrees Counterclockwise Orthogonal Model Error Azimuth Angle e.g. {-1,-2,-5,-2, } Group of environments = distribution of offsets Offset ANOVA Variation is predicted by: Type of environment Antenna gain f (θ k ) Observation point (negligible) Therefore (Type, antenna gain) offset distribution Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

37 Environment Parameters Antenna a, bin k Arc of azimuth centered at θ k. Fitted offset is Off k E[Off k ] = f a (θ k ) gain coefficient Off k Nor(E[Off k ], σ(offset)) Signal Nor(Off k, σ(signal)) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

38 Environment Parameters Antenna a, bin k Arc of azimuth centered at θ k. Fitted offset is Off k E[Off k ] = f a (θ k ) gain coefficient Off k Nor(E[Off k ], σ(offset)) Signal Nor(Off k, σ(signal)) Environment K gain S off S ss Open Outdoor Urban Outdoor LOS Indoor NLOS Indoor Table: Summary of Regression Results: Gain-offset regression coefficient (K gain ), offset residual std. error (S off ), and signal strength residual std. error (S ss ). Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22

39 Thank you Contact: Measurements: Simulation software (Qualnet patch):

40 Bin Sizes Residual Std. Error, db Residual Error Relative to Bin Count (Individual Data Sets Overlaid on Box Plot) Parabolic Outdoor A Parabolic Indoor A Patch Outdoor A Parabolic Outdoor B Patch Outdoor B Patch Indoor A Parabolic Indoor B Parabolic Indoor C Patch Indoor B Patch Indoor C Array Outdoor A Number of Fitting Bins (Azimuth) Eric Anderson (CU Boulder) Modeling Environmental Effects... WiNMee / 22