What Are The Optimal Parameters For Calibrating The COST 231 Hata Model To Accurately Predict Path Loss In A Dense Urban Environment With A Mix Of High-rise And Low-rise Buildings, Considering The Impact Of Foliage And Terrain Roughness On Radio Wave Propagation At Frequencies Between 2.4 GHz And 5 GHz?

To calibrate the COST 231 Hata model for a dense urban environment with mixed high-rise and low-rise buildings, considering foliage and terrain roughness at frequencies between 2.4 GHz and 5 GHz, follow these steps:

1. Base Model Selection

• Model Choice: Use the COST 231 Hata model as the base, which is suitable for urban areas and extends the frequency range up to 2 GHz. For frequencies beyond this, further adjustments are necessary.

2. Parameter Adjustments

a. Frequency Exponent

• Adjustment: Increase the frequency exponent from the standard 33.9 to account for higher path loss at frequencies up to 5 GHz. A suggested increase is to a value between 35 and 40.

b. Base Station Height Exponent

• Consideration: In dense urban areas, the impact of base station height (hb) may be less pronounced due to surrounding high-rise buildings. The exponent might be less negative to reflect reduced impact, but this depends on whether the base station is above or below rooftop level.

c. Mobile Height Factor (a(hm))

• Adjustment: Modify the mobile height factor to account for the urban canyon effect. The standard factor is ${ a(hm) = 3.2 (\log_{10}(11.75 hm))^2 - 4.97 }$. Calibration may require adjusting this to better fit the dense urban environment.

d. Distance Exponent

• Adjustment: Increase the distance exponent to reflect the rapid path loss in dense urban areas. The term ${ (44 - 6.55 \log_{10}(hb)) }$ may need to be larger to indicate a steeper increase in path loss with distance.

3. Additional Correction Factors

a. Foliage

• Addition: Include an empirical correction factor for foliage. Typical values range from 10 dB to 20 dB, depending on foliage density.

b. Terrain Roughness

• Addition: Add a correction for terrain roughness, typically in the range of 5 dB to 10 dB, to account for scattering effects in uneven terrain.

4. Calibration Process

• Measurement: Conduct field measurements of path loss across various locations in the target environment.
• Regression Analysis: Use the collected data to perform regression analysis and adjust model parameters to minimize prediction errors.

5. Final Model

• Formulation: Incorporate the adjusted parameters and additional corrections into the model to enhance accuracy for the specific environment.

Summary

The calibrated model will have adjusted parameters for frequency, base station height, mobile height, and distance, along with added corrections for foliage and terrain. This approach ensures the model better predicts path loss in the specified dense urban environment.