Vertically Polarized Antennas

[snabeel03]

Guys,

Why we use vertically polarized TX/RX antennas in cellular telephony?

[pathloss]

Don't we use XPol polarized Antennas in cellular networks? :L

The reason for this is that your holding your mobile not vertically but at a certain angle.

[snabeel03]

Thanks.Can you please tell me the difference between Vertical polarization and Cross polarization?

In Cross Polarization,TX antenna(BTS antenna) ,EMF is at right angle to RX antenna(Mobile)? Please correct me if I am wrong.

[mimoX]

When vertical polarization is used, less interference is produced or picked up because of strong vhf and uhf broadcast transmissions (television and fm radio). This is because vhf and uhf transmissions use horizontal polarization. This factor is important when an antenna must be located in an urban area having several television and fm broadcast stations.

[firstmaxim]

Don't we use XPol polarized Antennas in cellular networks? :L

The reason for this is that your holding your mobile not vertically but at a certain angle.

On the other hand, the reason is to offset the impact of fast fading. The fading on the two sets of antennas would have little correlation with one another. So, if one antenna receives signals undergoing a fade, the other is less likely to receive the signal with fade. However, note that these antennas can only be used only in strong multipath environments (urban) and have little benefit in rural environments.

[proy1_10]

vertical pol. has better conditions to propagation in urban environment

[mobilek530]

X polarized is used in Rural and Urban.
Advantage is compact size and having Diversity Gain

[firstmaxim]

X polarized is used in Rural and Urban.
Advantage is compact size and having Diversity Gain

I agree with you that it is compact and contributes to reduction of visual pollution, but diversity gain of X pol is a secondary advantage. You can use X-pol in rural areas, but you will not benefit from it, because of the poor multipath characteristics of a rural terrain. Instead, opt for space diversity in rural terrains.

[mobilek530]

Dear

As per technical understanding , it is quite right but implementation of Space Diversity is costly and difficult.

Regards


Please add repu & Thanks.

[snabeel03]

Thanks Everyone!

Can you please tell me how to add reputation to you guys?
Just clicking thanks?

[dekili]

Actually, vertical polarization has lower losses than horizontal. You can find curves in any book about the radio-planning and I can post them here if you needed. Single polarization (usually vertical) is used in fixed wireless where you can have good alignment and high link budget. Cellular antennas are dual polarized (X polarized) in order to make loss in alignment smaller. You can use space diversity in order to get better signal to noise ratio in rural areas having antennas spaces several wavelengths or you can use same configuration in urban environment to get MIMO effect that will lead to greater capacity. Depending on the selected algorithm for signal combining from antennas, you can get different results.
If you need more information I can post some docs here but it would be good to say what you really need.

[firstmaxim]

Actually, vertical polarization has lower losses than horizontal. You can find curves in any book about the radio-planning and I can post them here if you needed. Single polarization (usually vertical) is used in fixed wireless where you can have good alignment and high link budget. Cellular antennas are dual polarized (X polarized) in order to make loss in alignment smaller. You can use space diversity in order to get better signal to noise ratio in rural areas having antennas spaces several wavelengths or you can use same configuration in urban environment to get MIMO effect that will lead to greater capacity. Depending on the selected algorithm for signal combining from antennas, you can get different results.
If you need more information I can post some docs here but it would be good to say what you really need.



Good post. I would welcome any docs containing empirical data on this topic.

[dekili]

Good post. I would welcome any docs containing empirical data on this topic.

Could you be more specific? What part you are interested in? I can try to find something... Regarding the MIMO and AAS part, it is hard to find empirical data since it depends on vendor mostly and it is related to the resource scheduler algorithm selected. We can basicly find information from vendors about at what signal to noise ratio MIMO starts acting as AAS and vice versa. From the theoretical point, there are books describing algorithms and providing better insight, like MIMO Wireless Communications,ISBN 0521873282, or Coding for MIMO Communication Systems, ISBN: 0470028092. I am not posting them here since they are not the only choice for this subject and they could be easily find on the net...

[dane_2k2]

vertically polarized antenna is more susceptible in rain attenuation.

[blind shadow]

In a layman's term, vertical polarization is the same as an antenna stood vertically... By this means, the propagation of waves is also vertical overcoming the collision of atmospheric effects such as rains.. Imagine if the propagation is horizontal it is more likely affected by rain (as it is perpendicular to the rain drops/f1 layers). Unlike with vertical propagation that is parallel. (i hope this one helps)

[blind shadow]

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