Hata Model for Urban Areas

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The Hata Model for Urban Areas, also knows as the Okumura-Hata model for being a developed version of the Okumura Model, is the most widely used model in radio frequency propagation for predicting the behaviour of cellular transmissions in built up areas. This model incorporates the graphical information from Okumura model and develops it further to realize the effects of diffraction, reflection and scattering caused by city structures. This model also has two more varieties for transmission in Suburban Areas and Open Areas.

Hata Model predicts the total path loss along a link of terrestrial microwave or other type of cellular communications.

1 Applicable To / Under Conditions
2 Coverage
3 Mathematical Formulation
4 Points to note
5 Limitations
6 Further reading
7 See also

[edit] Applicable To / Under Conditions

This particular version of Hata model is applicable to the transmissions inside cities.

This model is suited for both point-to-point and broadcast transmissions.

PCS is one more extension to the hata model. Walfisch and bertoni Model is further advanced.

[edit] Coverage

Frequency: 150 MHz to 1500 MHz

Transmitter Height: up to 200 m

Link distance: less than 20 km

[edit] Mathematical Formulation

Hata Model for Urban Areas is formulated as,

$L_U \; = \; 69.55 \; + \; 26.16 \; \log f \; - \; 13.82 \; \log h_B \; - \; C_H \; + \; [44.9 \; - \; 6.55 \; \log h_B] \; \log d$

For small or medium sized city,

$C_H \; = \; 0.8 \; + \; (\; 1.1 \; \log f \; - \; 0.7 \; ) \; h_M \; - \; 1.56 \; \log f$

and for large cities,

$C_H \; = \begin{cases}\;8.29 \; (\; \log ({1.54 h_M}))^2 \; - \; 1.1 \; \mbox{ , if } 150 \le f \le 200 \\ \; 3.2 \; (\log ({11.75 h_M}))^2 \; - \; 4.97 \; \mbox{ , if }200 < f \le 1500 \end{cases}$

Where,

$L_U\;$ = Path loss in Urban Areas. Unit: decibel (dB)

$h_B\;$ = Height of base station Antenna. Unit: meter (m)

$h_M\;$ = Height of mobile station Antenna. Unit: [meter(m)

$f\;$ = Frequency of Transmission. Unit: megahertz(MHz).

$C_H\;$ = Antenna height correction factor

$d\;$ = Distance between the base and mobile stations. Unit: kilometer (km).

[edit] Points to note

The term ‘’’small city’’’ means a city where the mobile antenna height not more than 10 meters. i.e. $1 \; \le h_M \; \le 10 m$

[edit] Limitations

Though based on Okumura Model, Hata model does not provide coverage to the whole range of frequencies covered by Okumura Model. Hata model does not go beyond 1500 MHz while Okumura provides support for up to 1920 MHz.