1. For macrocell Outdoor Propagation Model 1

2. Okumura Model  wholly based on measured data - no analytical explanation  among the simplest & best for in terms of path loss accuracy in cluttered mobile environment  disadvantage: slow response to rapid terrain changes  common std deviations between predicted & measured path loss  10dB - 14dB  widely used for urban areas  useful for frequencies ranging from 150MHz-1920MHz frequencies can be extrapolated to 3GHz distances from 1km to 100km base station antenna heights from 30m-1000m 2

3.  Okumura developed a set of curves in urban areas with quasi-smooth terrain  effective antenna height:  base station h te = 200m  mobile: h re = 3m  gives median attenuation relative to free space (A mu )  developed from extensive measurements using vertical omni- directional antennas at base and mobile  measurements plotted against frequency 3 Okumura Model

4. Estimating path loss using Okumura Model  1. determine free space loss L F, between points of interest  2. add A mu (f,d) and correction factors to account for terrain 4 L 50 (dB)= L F + A mu (f,d) – G(h te ) – G(h re ) – G AREA L 50 = 50% value of propagation path loss (median) L F = free space propagation loss A mu (f,d) = median attenuation relative to free space G(h te ) = base station antenna height gain factor G(h re ) = mobile antenna height gain factor G AREA = gain due to environment

5.  Four steps:  a) calculate free-space path loss at the considered distance and carrier frequency  b) add median attenuation at the considered distance and carrier frequency  c) subtract the TX and RX antenna gains (see following formulas)  d) subtract the gain due to the specific environment.The values of A μ (f c, d) and GAREA are obtained from Okumura empirical plots 5 Estimating path loss using Okumura Model

6. 6 G(h te ) = 10m < h te < 1000m G(h re ) = h re  3m G(h re ) = 3m < h re <10m model corrected for -  h = terrain undulation height - isolated ridge height - average terrain slope - mixed land/sea parameter Estimating path loss using Okumura Model

7. Okumura-Hata model cont.  3 types of prediction area :  Open area : open space, no tall trees or building in path  Suburban area : Village Highway scattered with trees and house. Some obstacles near the mobile but not very congested  Urban area : Built up city or large town with large building and houses. Village with close houses and tall 7

8. 8 Median Attenuation Relative to Free Space = A mu (f,d) (dB)

9. Correction Factor = G AREA (dB) 9

10. Hata Model  empirical model of graphical path loss data from Okumura  predicts median path loss for different channels  valid over UHF/VHF band from 150MHz-1.5GHz  charts used to characterize factors affecting mobile land propagation  standard formulas for approximating urban propagation loss  correction factors for some situations  compares closely with Okumura model as d > 1km  large mobile systems  incorporates the graphical information from Okumura model and develops it further to realize the effects of diffraction, reflection and scattering caused by city structures 10

11. Hata Model cont… 11 ParameterComment L 50 50th % value (median) propagation path loss (urban) fcfc frequency from 150MHz-1.5GHz h te, h re Base Station (30-200m) and Mobile antenna height (1-10m)  (h re ) correction factor for h re, affected by coverage area dTx-Rx separation (1-20km) L 50 (urban)(dB) = 69.55 + 26.16log 10 f c – 13.82 log 10 th e –  (h re ) + (44.9-6.55h te )log 10 d

12. 12 Mobile Antenna Height Correction Factor for Hata Model  (h re ) Comment (1.1log 10 f c - 0.7)h re – (1.56log 10 f c - 0.8)dBMedium City 8.29(log 10 1.54h re ) 2 – 1.1 dB Large City (f c  300MHz) 3.2(log 10 11.75h re ) 2 – 4.97 dBLarge City (f c > 300MHz) L 50 (dB)Comment L 50 (urban) - 2[log 10 (f c /28)] 2 – 5.4Suburban Area L 50 (urban) - 4.78(log 10 f c ) 2 - 18.33log 10 f c - 40.98 Rural Area Hata Model for Rural and Suburban Regions represent reductions in fixed losses for less demanding environments

13. PCS Extension to Hata Model 13 L 50 (urban)(dB) = 46.3 + 33.9logf c – 13.82 logh te –  (h re ) + (44.9-6.55h te )logd + C M C M = 0dB for medium sized cities C M = 3dB metropolitan centers f c = frequency from 1500MHz - 2 GHz h te = 30m-200m h re = 1m-10m d = 1km-20km extend Hata model to 2GHz

14. Example 5  Suppose you received a license to operate at frequency of 1.7 GHz transmitting 5W into a 10dB gain antenna at a height of 30m above the ground. Your portable receiver having an antenna gain of 2dB and height of 1m above the ground level. The portable receiver can be used at a distance of 5km from base station. With this information and using charts from Okumura model estimate the received signal at portable receiver for urban, suburban and open area. 14

15. Example 6  Find the median path loss using Okumura’s model for d =50 km, h te =100m, h re =10m in a suburban environment. If the base station transmitter radiates an EIRP of 1kW at a carrier frequency of 900MHz, find the power at the receiver(assume a unity gain receiving antenna). 15