Rf prediction %26 planning training 1.0
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Rf prediction %26 planning training 1.0

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  • 1. By Project & Technical Support Department Mar 2003UTSI CONFIDENTIAL
  • 2. Base Station Antenna Mobile Radio environment (Top View) Propagation Path Loss region Multipath Fading RegionThree Basic mechanism that effects signalpropagation of mobile communicationSystem: • Reflection • Diffraction • ScatteringUTSI CONFIDENTIAL
  • 3. RF Propagation In Mobile communication environment the propagation is influenced by the various factors such as:  Reflection • Occurs when a propagating electromagnetic wave strikes a smooth surfsce with a very large dimensions compared to the RF signal wavelength Example - Ground reflected waves  Diffraction • Occurs when the radio path between the transmitter and receiver is obstructed by a dense body with the large dimensions compared to the wavelength. • Accounts for the RF energy traveling from transmitter to receiver without using line of sight path between the two. Example - Obstruction hills, irregular terrain and sharp edged building corners  Scattering • Occurs when a radio wave impinges on either large rough surface or any surface whose dimensions are on the order of the signal’s wavelength or less • Cause reflected energy spread out in all directions Example - urban environment - objects like lamp posts, street signs, foliageUTSI CONFIDENTIAL
  • 4.  Multipath Fading • The presence of reflecting objects and scatterers in the channel creates a constantly changing environment that dissipates the signal energy in amplitude, phase and time. This results in fluctuations in signal strength, thereby inducing fading, distortion or both  Speed of Mobile • The relative motion between the base station and the mobile results in random frequency modulation due to different Doppler shifts on each of the multipath components.  Speed of the surrounding Objects • The object that move at a greater rate that the mobile would induce a time varying Doppler shift on multipath components and thus results in fading and distortion.UTSI CONFIDENTIAL
  • 5. • In mobile environment, the rate of change of RF signal over the distance is not necessarly to follow either R-2 or R-4. Jian De - Com m ercial CS Height is 21 mtrs. 80 70 60 LOS outdoor 50 No LOS outdoor RSSi (dBuV) Indoor 40 CF-LOS outdoor 30 CF-No LOS outdoor dBuV= -22.5log(d) + 106.68 -bef ore breal point, Stdev. CF-Indoor dBuV= -88.3log(d) + 243.568 -af ter breal point, Stdev. 20 dBuV= -59.5log(d) + 171.4, Stdev. 4.06dB 10 dBuV= -6log(d) + 58.207 -before breal point, Stdev. dBuV= -77.5log(d) + 204.437 -af ter breal point, Stdev. 0 10 100 1000 Distance (mtrs)UTSI CONFIDENTIAL
  • 6. • In Mobile environment, the RF signal propagation is statistically distributed unlike in Free Space environment doe to the large scale and small scale fading and distortion. • The RSSI over the distance is normally distributed with standard Deviation 8 dB. The Solid line represents the mean curve of the RSSI signal level at a given distance from the Base Station. I.e. The Probability is 50% • Any RF Propagation equation represents mean curve RSSI is normally distributed IS RS DistanceUTSI CONFIDENTIAL
  • 7. Three important Statistical Distributions 1 Normal Distribution 2 Binomial Distribution 3 Poisson DistributionUTSI CONFIDENTIAL
  • 8. Statistics- Basics 1 n Mean( ) µ ∑ Xn n 1 1 n Variance ( ) σ2 ∑ (xn − µ )2 n −1 1 1 n Standard Deviation ( ) σ ∑ (xn − µ )2 n −1 1UTSI CONFIDENTIAL
  • 9. Normal Distribution Central Limit Theorem • The frequency distribution of a large random sample size ‘n’ is Normal, a bell shaped curve • The sampling mean of a large random sample size of ‘n’ is normally distributed., a bell shaped curve. Normal DistributionUTSI CONFIDENTIAL
  • 10. The Standard Deviation determines the shape of the curve Normal Distribution Normal Distribution σ=0.5 Probability Probability σ=2 -∝ µ +∝ µ f(X=x) -∝ f(X=x) +∝ Normal Distribution σ=1 Probability -∝ µ +∝ f(X=x)UTSI CONFIDENTIAL
  • 11. Area under the curve is 1 and the below or above mean is 0.5 Normal Distribution Normal Distribution Normal Curve N(µ, σ) Probability Probability σ Probability = 0.5 -∝ µ f(X=x) +∝ -∝ µ f(X=x) +∝ Normal Distribution µ= Mean σ= Std. Dev Probability Probability = 1 -∝ µ +∝UTSI CONFIDENTIAL f(X=x)
  • 12. 68%-95%-99.7% Rule Normal Distribution Normal Distribution Probability = 0.68 Probability = 0.95 Probability Probability (CDF) (CDF) -∝ - 1σ µ f(X=x) +1σ +∝ -∝ -2σ µ f(X=x) +2σ +∝ Normal Distribution Probability = 0.997 Probability (CDF) -∝ -3σ µ f(X=x) +3σ +∝UTSI CONFIDENTIAL
  • 13. Standard Normal Curve Standard Deviation (σ ) = 1 Mean (µ) = 0 Standard Normal Distribution σ=1 Probability -∝ -Z 0 +Z +∝ f(X=x)UTSI CONFIDENTIAL
  • 14. How to Convert a Normal Curve to Standard Normal Curve x−µ • Standard Transformation is z= σ Standard Normal Distribution Normal Distribution σ σ=1 Probability Probability -∝ +∝ -x µ +x -z 0 f(X=x) +z -∝ f(X=x) +∝UTSI CONFIDENTIAL
  • 15. Table of z 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09-0.3 0.3821 0.3783 0.3745 0.3707 0.3669 0.3632 0.3594 0.3557 0.3520 0.3483-0.2 0.4207 0.4168 0.4129 0.4090 0.4052 0.4013 0.3974 0.3936 0.3897 0.3859-0.1 0.4602 0.4562 0.4522 0.4483 0.4443 0.4404 0.4364 0.4325 0.4286 0.4247-0.0 0.5000 0.4960 0.4920 0.4880 0.4840 0.4801 0.4761 0.4721 0.4681 0.46410.0 0.5000 0.5040 0.5080 0.5120 0.5160 0.5199 0.5239 0.5279 0.5319 0.53590.1 0.5398 0.5438 0.5478 0.5517 0.5557 0.5596 0.5636 0.5675 0.5714 0.57530.2 0.5793 0.5832 0.5871 0.5910 0.5948 0.5987 0.6026 0.6064 0.6103 0.61410.3 0.6179 0.6217 0.6255 0.6293 0.6331 0.6368 0.6406 0.6443 0.6480 0.6517UTSI CONFIDENTIAL
  • 16. Standard Normal Distribution CalculatorUTSI CONFIDENTIAL
  • 17. Confidence Level, Confidence Interval & Margin of Error • The area under the curve( i.e. Probability / CDF) C is C% Confidence Level • The distance between boundaries at equal distances both sides from mean C %Confidence Interval • The distance between mean and one side of the boundary is C% Margin of error Normal Distribution Standard Normal Curve N(µ =0, σ =1) Probability 1−C Probability = C 1−C α= α= 2 2 -∝ -z* µ f(X=x) +z* +∝UTSI CONFIDENTIAL
  • 18. • In mobile environment, the rate of change of RF signal over the distance is not necessarly to follow either R-2 or R-4. Jian De - Com m ercial CS Height is 21 mtrs. 80 70 60 LOS outdoor 50 No LOS outdoor RSSi (dBuV) Indoor 40 CF-LOS outdoor 30 CF-No LOS outdoor dBuV= -22.5log(d) + 106.68 -bef ore breal point, Stdev. CF-Indoor dBuV= -88.3log(d) + 243.568 -af ter breal point, Stdev. 20 dBuV= -59.5log(d) + 171.4, Stdev. 4.06dB 10 dBuV= -6log(d) + 58.207 -before breal point, Stdev. dBuV= -77.5log(d) + 204.437 -af ter breal point, Stdev. 0 10 100 1000 Distance (mtrs)UTSI CONFIDENTIAL
  • 19. • In Mobile environment, the RF signal propagation is statistically distributed unlike in Free Space environment doe to the large scale and small scale fading and distortion. • The RSSI over the distance is normally distributed with standard Deviation 8 dB. The Solid line represents the mean curve of the RSSI signal level at a given distance from the Base Station. I.e. The Probability is 50% • Any RF Propagation equation represents mean curve RSSI is normally distributed IS RS DistanceUTSI CONFIDENTIAL
  • 20. Example  If the mean curve tells you that the RSSI at 100 mtrs from the base station is 40 dBuV, at most (equal or less than) what should be RSSI level for 95% probability when The signal propagation has the standard deviation of 8dB?UTSI CONFIDENTIAL
  • 21. x−µ z= Normal Distribution σ  If the mean curve tells you that the RSSI at 100 mtrs from the base station is 40 dBuV, at most (equal or less than) what should be RSSI level Probability for 95% probability when The signal propagation has the standard deviation of Probability = C 8dB? ∀ µ=40; σ=8 • We have to find out ‘x’ value from the above equation. • From the table, for the probability=0.95 -∝ µ +z +∝ f(X=x) (95%) , Normal Distribution z = +1.645 • When we substitute z, µ, σ values in above equation, Standard Normal Probability Curve N(µ =0, σ =1) x= 53.2 dBuV Probability = 0.95 • The RSSI level of 53.2dBuV or above will have the probability of 95% • OR, 95% of the time the RSSI level at that point is 53.2 dBuV or more -∝ µ f(X=x) +1.645 +∝UTSI CONFIDENTIAL
  • 22. Example The RF propagation in a typical urban area is characterized by the relation, RSSI(in dBuV) =171-59.5Log(d inMtrs.) with the standard deviation of 8dB. The threshold signal required for the PS’s successful operation is 32 dBuV. What is the radial distance covered by the base station? What should be the radial distance at which it is 90% coverage confidence (boundary coverage confidence)?UTSI CONFIDENTIAL
  • 23. The RF propagation in a typical urban area is characterized by the relation RSSI(in dBuV) =171-59.5Log(d inMtrs.) with the standard deviation of 8dB. The threshold signal required for the PS’s successful operation is 32 dBuV. What is the radial distance covered by the base station? What should be the radial distance at which it is 90% coverage confidence (boundary coverage confidence)? • The relation RSSI = 171-59.5 Log(d) is a mean curve for the RF propagation at a Normal Distribution given urban area. • From the relation we can find out the RSSI level (in dBuV) for various distances’ d’. Probability • For the RSSI level of 32 dBuV, using the Probability = 0.5 above equation, the radial distance covered by the base station is , 32=171-59.5Log(d), d=216 mtrs. 368 m 216 Mtrs) -∝ 32 f(X=x) +∝ • Since the relation is the mean curve, the boundary coverage confidence at 216m radius is 50% (I.e. RSSI 32dBuV and above)UTSI CONFIDENTIAL
  • 24. • Now, for the 90% coverage confidence, the probability for RSSI is equal to 32 dBuV and above should be 90%. Normal Distribution We use the value 32dBuV since it is threshold level in our problem.• So, our strategy is to find out the ’µ ‘ value for which Standard Normal the probability for RSSI is equal to and above 32 dBuV Curve N(µ =0, σ Probability is 90%. Finally use this ‘µ’ value in the equation, =1) Probability = 0.90 RSSI=171-59.5Log(d) to find out the radial distance ‘d’. This is the coverage for 90% confidence. α=0.10• If the probability for RSSI ≥ 32 is 90%, then Probability for RSSI ≤ 32 is 10%. -∝ Z=-1.282 µ f(X=x) +∝• Find out ‘ z’ from the table for the probability = 0.10. From the Table, z=-1.282 Normal Distribution• In our problem x=32 dBuV, σ=8 dB, z=-1.282 x−µ• Substitute the above values in z= to get ’µ ‘ . σ Probability Normal Curve N(µ =42, σ =8) Probability = 0.90∀ µ = 42dBuV . This is the RSSI value at which the coverage confidence is 90% α=0.10• From the the equation RSSI=171-59.5Log(d), d=147m• 147m radius from the base station would provide -∝ 32dBuV µ=42dBuV f(X=x) +∝UTSI CONFIDENTIAL
  • 25. Cell Edge Confidence Contours for RSSI=171-59.5Log(d) & Std. Dev=8dB 216m Radius 50% cell edge confidence 157m Radius 85% cell edge confidence 147m Radius 90% cell edge confidence 130m Radius 95% cell edge confidence Base StationUTSI CONFIDENTIAL
  • 26. Cell Boundary (or Edge) confidence Vs Cell Area Confidence • In our last example we have seen how to calculate boundary coverage confidence (I.e. percentage of time the signal is to exceed the threshold at the boundary). • It is possible to relate and compute the percentage of area covered within the boundary. i.e. the percentage of area with a received signal that is equal or greater that threshold RSSI level. • It is computed from the below relations: Cell Edge Confidence Cell Area Confidence from Cell Edge Confidence    1   1 − x ⋅ y    1− 2⋅x⋅y       1  ∞ -x 2  F u = ⋅ 1 − erf ( x) + e   y2  ⋅ 1 − erf    Confidence Edge = 1 -   ∫ e 2 dx  2    y    2 ⋅π  µ −10⋅n⋅log ( r )        δ 10 ⋅ n ⋅ log10e  n = Path loss exponent y = r = Normalized cell radius(on the cell boundary, r = 1) δ⋅ 2  −µ x = δ = Log normal shadow standard deviation δ⋅ 2  2 x erf ( x) = ⋅ ∫ e − t dt 2    1   p 0 ∞ -x 2   2 ⋅π  ∫⋅log( 2r ) dx = Outage probability (cell edge) e µ = Log normal shadow margin for a given x o   µ −10⋅n  (see log normal shadow margin section for equation)  δ   n = Path loss exponent It is the percentage of time when a receiver experiences shadowed performance during shadowing. δ = Log normal shadow standard deviation in dB UTSI CONFIDENTIAL
  • 27. Comparison of Cell Edge - Cell Area Confidence (R^4 Propagation, 8 dB Sigma) 110% 100% Confidence Level (%) 90% Cell Edge 80% Cell Area 70% 60% 50% 0.00 1.01 2.03 3.08 4.20 5.40 6.73 8.29 10.25 13.16 24.72 Log Norm al Fade Margin (dB)UTSI CONFIDENTIAL
  • 28. Micro Cell RF Propagation Model • The commonly used models for cellular technology , especially for GSM environment are, Okumara, Lee and Hata models. These models are derived based on the emprical data collected through extensive experiments at various citiessuch as New York, Tokyo, etc… • However these models are more applicable for the range one Km and above. I.e for macro cellular environment. • PHS technology is based on micro cell concept. The Cell radius is 200-300 Mtrs. • Akayama and Kaji first published a RF model for such micro cells. • UTStarcom developed a model based on its extensive experiments at various cities in China and based on the resulted experimental data. • Combining the experimental data and the statistical techniques, as discussed so far, a software tool is developed to predict the RF coverage and thus to design the RF network.UTSI CONFIDENTIAL
  • 29. Composite 500mW CS Micro-Cell Propagation Measurement LO S r eet - S de S t i LO U ban- R S r es I ndoor N LO U ban- R o S r es I ndoor LO O d Tow A l ey S l n l no LO S r eet - S de S t i no LO G t I ndoor S vm O d Tow I ndoor l n 80. 0 70. 0 60. 0 uV 50. 0 dB 40. 0 30. 0 20. 0 10. 0 10 100 1000 D st ance iUTSI CONFIDENTIAL
  • 30. RF Design Tool - MicroWizard Introduction MicroWizard is a RF network design tool, with a laconic interface, a simple operation and powerful function. We can availably design network with given environments through the tool. • We can systematically decide the number of CS per a coverage area • Calculate the commonly recognized coverage radius for the 500mW CS • When we adjust various design parameters of an RF network, we will concretely know how does each factor impact the performance of the entire network • We can design new network more accurately and effectively • MicroWizard can run in WIN98/WIN2000 operating system, with graphic interface and simple operation.UTSI CONFIDENTIAL
  • 31. Parameters of the MicroWizardUTSI CONFIDENTIAL
  • 32. Meaning of Some Parameter Type Definition Dense Urban A complicated area mixed with 8-15 layers building and 15-20 layers intensive buildings, with 4 main streets and 2 small roads and few or no more trees Urban A complicated area mixed with 4-6 layers and 6-15 layers commercial /apartment houses/marketplace, with 4 main streets and 2 small roads and few or no more trees. Relation to dense urban ,the building is not so high and intensive. Suburban Generally less than 4 layers houses along the expressway/main road. The houses and hotels are arranged with 1-2 alignments at the outside town, there is few and middle quantity vegetation highway smooth road Rural There is self-governed small houses and independent/field.UTSI CONFIDENTIAL
  • 33. Meaning of Some Parameters Type Definition Plane Earth This is the smooth and flat ground with a lot of spacing such as wide roads, parks in between the builit up area of 6-8 story buildings. Rolling hills Hilly terrain with frequent ups and downs. Rugged terrain The area Uneven, rocky and rough trrain Significant The area with lake or river lake/river Crowded low-lvl The area with 1or 2 story houses with very less spacing or housing no spacing between the houses and a very very narrow streets of 1-1.5 metres. Lossy ground/soil The area with Muddy and watery soils Crowded hi-rise The area with high rised buildings of more than10 story spacing buildings separated by wide roadsUTSI CONFIDENTIAL
  • 34. Meaning of Some Parameters Type Definition None This is used mainly when out door coverage is to be provided Such as on high ways, cover the lake , river etc,… 13dB thin wall The buildings with wall size of 4-6 thickness-especially old type independent houses, apartments, small shops,etc… Thin wall w./ Roof Old type houses with roof bricks and no floors with walls of 4” Leakage thickness where the CS is place in such a way that the RF signal can reach the indoor through the roofs Medium wall The buildings with 6-9” thickness wall. Especially commercial buildings, Private and Govt. office buildings,shopping malls apartment houses etc,… Thick The buildings with 9” and above thickness of wall. building/wall Rain fades Rainy places Dense Vegetation The place with dense trees and plantations.UTSI CONFIDENTIAL