Before tuning physical parameter or
antenna parameter an engineer should have clear understanding on flowing issue:
A) Basic
principle of Antenna.
B) Antenna
selection procedure for different radio environment.
C) Antennacharacteristics and Classification.
An antenna is a passive device
which can transmit and receive radio waves. When antenna transmits its convert
RF current into electromagnetic (EM) waves and when it receives converts
electromagnetic (EM) waves into RF currents.
For every radio network, network
parameter may be categorized into two parts; one is physical parameter and
another is logical parameter. Due to improper combination of physical parameters
WCDMA network service may hamper at a large scale. Flowing physical parameter
need to tune for optimum network service:
1. Antenna’s
heights.
2. Antenna’s
Electrical Tilt.
3. Antenna’s
Mechanical Tilts.
4. Antenna’s Azimuth or Orientation.
The most probable reason of
Physical Parameter tuning is listed below:
a) Poor coverage issue at indoor and outdoor.
b) Signal overshooting issue.
c) Pilot pollution
reduction issue.
d) Cluster
rearrangement/load balancing or traffic sharing issue.
e) Different purpose
optimization such as new site/cell addition and deletion.
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| WCDMA Radio Network serving area |
Antenna Heights: An Antenna height is one of the most significant
physical parameter of WCDMA network. By tuning antenna’s height we can control coverage
area of WCDMA network. That is antenna height is directly proportional to the
maximum coverage area. Depends on the elevation (Sea level height) of
geographical surface theoretical value of antenna heights may differ.
One of the alternative soft
parameter of Antenna height is Transmit Power. Alternative Physical parameters are Electrical
Tilt and Mechanical Tilt.
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| Antenna height VS Coverage |
Antenna’s Electrical Tilt: The antenna’s Electrical Tilt
represents an electrical inclination or electrical angle of the antenna from
its axis. There are two types of electrical tilts; these are Up Tilt and Down Tilt.
Generally electrical Up tilt applies for expand coverage or to strengthen signal
and down tilt applies for shrinking coverage. Alternative Physical parameters of
Electrical tilt are Antenna heights and Mechanical Tilt.
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| Antenna Electrical Tilt |
Antenna’s Mechanical Tilt: Antenna’s Mechanical Tilt
represents a mechanical inclination or mechanical angle of the antenna from its
axis. There are two types of Mechanical tilts; these are Up Tilt and Down Tilt.
Generally Mechanical Up tilt applies for expand coverage and down tilt applies
for shrinking coverage. The tuning impact of antenna’s mechanical tilt is almost
similar with Antenna’s “Electrical Tilt”.
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| Antenna Electrical Tilt vs Mechanical Tilt |
Antenna’s Azimuth or Orientation: Generally WCDMA system uses highly directional cross
polarized (±45®) antenna. Here, Antenna’s Azimuth or Orientation represents on
which direction antenna faces. During the selections of WCDMA antenna we need
to consider few antenna characteristics such as polarity, horizontal and
vertical beam width, antenna gain, Maximum transmits power etc. Antenna’sazimuth is very useful parameter during the customer complain solution
process. If antenna beam width is 65®
and three cell site; then the maximum antenna azimuth tuning is ±20®.
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| Antenna Azimuth tuning proposal |
