4G antennas can operate under a MIMO environment. And this is considered one of its most significant features. MIMO stands for “Multiple Input Multiple Output” — our Internet modem makes use of this technology to deliver signals at warp speeds.
When it comes to Next-G signals and normal 3G, the accurate description we can give with regard to their broadcast is that they are highly polarized. The wave they produce would be traveling in an “up and down” fashion.
Compared to the LTE MIMO, the waves they produce are slanted polarized, with each wave rotating to about 45 degrees from the horizontal. Mirrored, this will render the first to be at 45 degrees while the other would be at 135 degrees.
It is a smart trick, which they call polarisation diversity. It lets your ordinary modem distinctly identify two streams of independent data over the exact and same frequency being designated by a cell tower.
Since our modem usually comes with two internal antennas that are primarily designed to receive one data stream, it makes it necessary to have on standby two separate antennas, external type.
There is no way we can make use of a “Y” patch lead or any other trick for that matter just to make it a good possibility to connect both modem ports into a single antenna, nor try to connect one, single port to both external antennas.
The modem itself is switching the MIMO on and off. The cell tower takes on the responsibility of determining whether the use of MIMO or not is viable, where transmitted and received signals are assessed in terms of their quality. This metric is referred to as CQI.
The modem is quite challenged when it needs to distinguish the two streams of data and the signal strength is slow or very poor in quality. This renders a certain threshold level to drop when the MIMO is off and the modem is operating only under one antenna.
Why So Much Fuss Over Interference?
The distinction that is existing between the signal strength and signal quality can’t be ignored all the time. The strength pertains to the information range where it can be interpreted correctly with respect to that particular waveform.
The SINR or the C/I+N Ratio is of prime value here since 4G antennas negotiate its radio index bearer concerning the interpreted carrier signal strength over the noise level plus the interference strength – which means to say that the lower interference is, the higher chance of C/I+N to be. Consequently, it should pave the way for a much faster coding scheme and modulation.
In any 4G network, the most prominent source of interference is no less than self-interference — this may come from the interference of other sectors originating from the base station, as well as from other similar base stations.
Interference can also come from other sources including systematic(natural), gamma radiation, thermal, and hostile (unnatural), including high voltage transmission, machinery, and illegal booster, etc.
By making sure the beamed transmission is focused on a particular direction, we are rendering the strength to the spike in one direction, right at the expense of all the others.
This can be taken advantage of to alleviate unnatural interference sources, including nearby machinery that tends to generate wideband noise as well as downplaying interference by virtue of reducing the strength of the interfering base station’s direction — all done and carried out while enhancing the target base station direction strength.