jason,
good definition 🙂 just 2 things to add : the link budget is usually rather balanced, or sometimes a little weak on the DL side. That’s because in a cell with more than 4 TRX, there are 2 combining stages. One combining stage removes 4.5dB of DL power. 2 stages remove 9dB of DL power !!
In UL, there are not such losses due to combining (indeed, there is no “combining” loss at all in UL).
In other words, cells with high number of TRXs are DL limited. Cells with less TRXs are usually balanced or slightly UL limited (depends on BTS sensitivity…)
2nd thing : downtilting the antennas are not going to improve UL or DL : the antenna has exactly the same pattern in UL and in DL. downtilt modifies the UL and the DL path loss in exactly the same way.
TMA, powering down, high power TRX, less combining stages, Rx diversity, Tx diversity… all those methods can favour one direction compared to the other.
Cheers,
pix