low frequency for uplink
Let’s take an example: GSM900 with 45MHz split between UL and DL, and a distance between Mobile and BS of 2 km.
UpLink = 900MHz => Free space path loss = 97.5dB
DownLink = 945MHz => Free space path loss = 97.9dB
So, is only 0.4 dB difference between UL and DL losses in free space, and probably adding fading and multipath there will be no difference.
In satellite communication is a different story due to greater distances, but not in cellular systems.