08-12-2012, 02:24 PM
CDMA 1900 MHz RF DESIGN.
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ABSTRACT
The project involves simulation of a real-time CDMA wireless system for providing cell
service to a particular area. The project starts with a Link Budget in which the customer
precisely tells what all he wants. Once all the data is obtained simulation is being done
using the Planet RF simulation tool. The entire area under consideration is divided into
cells. Models for Urban, Sub-urban and rural cell sites are being created. Once we are
done with loading all the database and creating good models, cell sites have been created.
Later predictions have been run over the entire area of coverage. Finally we have
simulated the entire network. Plots that tell about the entire coverage, the best server and
signal level at each corner have been obtained. Ultimately taking all these factors into
consideration a mobile system has been designed that does call processing, mobility
management and billing and will be handed over to the customer.
INTRODUCTION
In the current project a preliminary RF design for BTA 50 Boise, Idaho
has been done using the Planet RF simulation tool. The intention of this design is to
provide the cell counts required to support coverage and a 5- year capacity design for a
customer and a fixed CDMA operation. The design requirements and engineering
parameters in this design are assumed to be given by the customer (local cell network
provider) in any wireless project. The CDMA network standards that have been followed
throughout the project are taken from Nortel Networks.
BACKGROUND
What is CDMA: CDMA is a "spread spectrum” technology, which means that it spreads
the information contained in a particular signal of interest over a much greater bandwidth
than the original signal. When implemented in a cellular telephone system, CDMA
technology offers numerous benefits to the cellular operators and their subscribers. It has
the following advantages.
Capacity increases of 8 to 10 times than that of an AMPS analog system
and 4 to 5 times than that of a GSM system. Improved call quality, with better and more
consistent sound as compared to AMPS system. Simplified system planning through the
use of the same frequency in every sector of every cell.
The knowledge of the following terms and their application is imperative in
understanding the technicality of the project.
IMPLEMENTATION
Planet: This is software for simulating the entire network of wireless coverage we are
providing. To start with PLANET we created a definition file for PLANET. We created a
particular folder for the area we are considering for the coverage. In that folder all the
databases have been loaded. The databases that are loaded are antenna database, vector
database (i.e. which tells the primary and secondary roads and all the other roads going
through that area), clutters (i.e. residential, commercial, openlands, forest areas etc). Once
we are done with loading PLANET we started running simulations with that.
RESULTS
Finally we have simulated the entire network. We can see the plots, which tell about the
entire coverage and their respective signal levels. In order to cover the BTA (Boise)
along the interstate highway I-84 and state highway 95 and the counties along the
highway our design suggested the customer to install 68 bisector highway cell sites, 203
trisector cell sites to cover all the urban and suburban area in that BTA.We also came
with plots which shows the composite coverage area in the entire area. Plots (E-size)
which will give a clear idea of what the final coverage looks like have been also attached.
CONCLUSIONS AND SCOPE FOR FURTHER IMPROVEMENT
Any modification that results in the reduction of the number of cell sites that can be
designed, will be an ideal improvement. That can only be done by the efficient usage of
the Planet RF simulation tool.