Very few standards exist for fixed wireless systems, and you will need to purchase equipment from the same vendor for both sides of the connection to ensure interoperability. Radio Spectrum Fixed-wireless systems use frequencies allocated for such use from about 900 MHz to 40 GHz. The number of different bands can be bewildering, with multiple frequency bands assigned for private use and multiple bands assigned for carrier use. In addition, some bands are designated for licensed use while others can be used without a license. Yes, but only in a general sense.
Higher frequencies have some advantages over lower frequencies, but also suffer some drawbacks.
The principle advantage of higher frequencies is that there is more spectrum available for broadband applications. Most higher bandwidth systems use frequencies above 10 GHz. Antennas at these frequencies are smaller due to the smaller wavelengths, making systems easier to deploy. But with higher frequency, components demand more sophisticated technology, so systems cost more. Also, propagation distance for reliable communications decreases and the signal is more susceptible to weather conditions like rain and fog.