Multichannel Multipoint Distribution Service Coverage Planning for Addis Ababa City
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Date
2012-10
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Addis Ababa University
Abstract
Multichannel Multipoint Distribution Service (MMDS) is one of the currently used Fixed
Wireless Broadband (FWB) systems that provide multichannel broadcasting, broadband internet
and other interactive services. It works mostly at 2.5-2.7 GHz frequency band through terrestrial
propagation. As its name implies, it provides multiple television channels because of its high
frequency band. It is more cost efficient than cable and satellite broadcastings for relatively small
coverage areas like cities and towns.
Addis Ababa is a city with a population size of more than 4 million that have complex linguistic,
cultural, religious and ideological varieties. The city is the site for many diplomatic community
and hosts many international organizations. Moreover, it accommodates many international
conferences. Addis Ababa, which has now only few television channels, needs to benefit from
broadcast communication systems like MMDS that can provide far more number of channels
with relatively lower cost to foster its national and international values for maximum benefit.
In this thesis, coverage planning of MMDS, which is an integral part of the entire planning, is
carried out for Addis Ababa. In coverage planning, propagation models are used to predict the
path loss at a certain distance from the transmitter site considering terrain and other
environmental effects. The planning involves two steps; firstly, system dimensioning is done
using the Institute of Electrical and Electronic Engineering, IEEE 802.16 (Stanford University
Interim) model. Secondly, detail planning is accomplished using the International
Telecommunications Union Recommendation, ITU-R P.1546-5 model.
In coverage planning, the important parameters are the transmitter output power, number of
transmitters needed, locations of transmitters for maximum coverage, and the positions and
output powers of repeaters to cover small shadowed areas. Most of these parameters are
determined based on the propagation models used.
This work took 10 high altitude locations in the city as candidate sites for maximum coverage.
The result shows that one 70 meter transmitter with 57dBm output power located at a mountain
around Lebu area (South-Western part of Adds Ababa) and a 25 meter repeater with 32 dBm
MMDS Coverage Planning for the City of Addis Ababa Page V
output power located around Country Club Developers Homes (North-Eastern tip of Addis
Ababa) can cover 96.14% of the area of the city, which is satisfactory coverage.
Keywords
Multichannel Multipoint Distribution Service, Propagation models, Broadcasting, Coverage
planning, System dimensioning, detailed planning, ITU-R P.1546-5 model.
Description
Keywords
Multichannel Multipoint Distribution Service, Propagation models, Broadcasting, Coverage planning, System dimensioning, Detailed planning, ITU-R P.1546-5 model