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angle (ODA) is based on maximum service probability of low and high traffic volume scenarios.The simulation results indicate that an increase of the antenna height changes expectedly the optimum downtilt angle; 10 m increase in the antenna height corresponds roughly to 1 o increase of the ODA.For all network configuration, ODAs increase as a function of antenna height and decrease as a function of site spacing.Hence, with an optimum downtilt angle, network coverage is guaranteed, and simultaneously, other-cell interference is mitigated as efficiently as possible.For the 3-sectored configurations with 6 o vertical beamwidth, the optimum downtilt angle varies between 4.3 o-8.1 o depending on the network configuration and downtilt scheme.In the 3-sectored configurations with 12o vertical beamwidth, the evaluated optimum downtilt angles range between 3.5 o-10o (Table IV).

angle (ODA) is based on maximum service probability of low and high traffic volume scenarios. Hence, with an
optimum downtilt angle, network coverage is guaranteed, and simultaneously, other-cell interference is mitigated
as efficiently as possible. More detailed description of the definition method of ODA can be found from [15].
In the simulations, all downtilt angles are gradually increased in steps of 2
◦
.
Table IV gathers all optimum downtilt angles for all simulated network configurations. For all network
configuration, ODAs increase as a function of antenna height and decrease as a function of site spacing.
Generally, it can be also observed that the change of ODA from 1.5 km to 2.0 km site spacing than from
2.0 km to 2.5 km site spacing, hence indicating that a small downtilt angle should be always used. Moreover,
with 12◦
antennas, the required downtilt angles are expectedly higher than for 6
◦
antennas.
For the 3-sectored configurations with 6
◦ vertical beamwidth, the optimum downtilt angle varies between
4.3
◦–8.1
◦ depending on the network configuration and downtilt scheme. According to (7) and (8), the corresponding
downtilt angles would have been 0.8
◦–2.5
◦
and 3.8
◦–5.5
◦
. The simulation results indicate that an
increase of the antenna height changes expectedly the optimum downtilt angle; 10 m increase in the antenna
height corresponds roughly to 1
◦
increase of the ODA. On the other hand, site spacing has comparatively
smaller impact on ODAs, especially with larger site spacings. In the 3-sectored configurations with 12◦ vertical
beamwidth, the evaluated optimum downtilt angles range between 3.5
◦–10◦
(Table IV). With definitions of (7)
and (8), the downtilt angles would have been 0.8
◦–2.5
◦
and 6.8
◦–8.5
◦
, respectively. On average, the ODAs are
intuitively higher for the 12◦
than for 6
◦ beamwidth. However, the increase of ODAs is not as huge as one
could expect. One reason for even lower ODAs for 12◦ beamwidth are the interference conditions that differ due
to lower antenna gain and wider vertical spread of antenna pattern. Without any downtilt with 6
◦ beamwidth,
the signal power is more precisely directed towards the boresight, whereas antennas of 12◦ beamwidth provide