A radio system is built according to the following Figure. Sketch a Link Budget diagram that describes the system and determine the maximum range d [m] of the transmission.  There are various type of models for wireless channels: • Empirical models • based on measurements • linked to the environment and the parameters of the measurement campaign • Deterministic models • based on a fixed geometry (buildings, streets,…) • used to analyze particular situations • Physical-Statistical models • combination of deterministic models and statistics of various parameters (building heights, street width,…)  The Okumura model for Urban Areas is a model that was built using the data collected in the city of Tokyo, Japan.  The model is ideal for using in cities with many urban structures but not many tall blocking structures. The model served as a base for the .  Predicts average (median) .  “Accurate” within 10-14 dB in urban and suburban areas.  Frequency range: 150-1500 MHz.  Distance: 1 km- 100 Km.  BS height: 30m– 1000m.  MU antenna height: up to 3m.  The Okumura model is formally expressed as:

where, L = The median path loss. Unit: (dB)

LFSL = The Free Space Loss. Unit: Decibel(dB) AMU = Median attenuation.Unit: Decibel(dB) HMG = Mobile station antenna height gain factor. HBG = Base station antenna height gain factor. Kcorrection = Correction factor gain (such as type of environment, water surfaces, isolated obstacle etc.)

Find the median path loss using Okumura’s model for d=50 km, hte=100m, hre=10m in a suburban environment. If the base base station transmitter radiates an EIRP of 1 kW at a carrier frequency of 900 MHz, find the power at the receiver (assume a unity gain receiving anteena).  In wireless communication, the Hata Model for Urban Areas, also known as the Okumura-Hata model for being a developed version of the Okumura Model, is the most widely used radio frequency propagation model for predicting the behavior 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 for Urban Areas is formulated as:

 For small or medium sized city:  And for large cities:  Though based on the Okumura Model, the 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.

 Frequency range: 150 - 1500 MHz  Distance: 1 – 20 km  BS antenna height: 30- 200 m  MU antenna height: 1 – 10 m Correction Factors are: Large cities

2 ahmu   8.3log101.5hmu  1.1  f  200MHz dB

2 ahmu   3.2log1011.75hmu   4.97  f  400MHz dB

Average and small cities

ahmu   1.1log10f 0.7hmu 1.56log10f 0.8 dB Carrier frequency • 900 MHz,

BS antenna height • 150 m,

MU antenna height • 1.5m. Suburban Areas

2   f  Lplsu  Lplu  2Log10   5.4   28 

Open Areas

2 Lplo  Lplu  4.78(Log10 f ) 18.33Log f  40.94