I recommend that you approach the tower in the Diamond District from the Southern, or South-Western side. You need to be very careful here, because this area is being under scrutiny by, among others, several snipers. Try to eliminate, in the first place, those of the snipers that are occupying the rooftops around the one with the comms tower on it. Do this while attempting to stay hidden.
Only then, focus o the bandits occupying the main balcony. It is worth using the disruptor here, to deprive some of the enemies of the possibility to use the guns, and also eliminate, at least, one of them using a glue grenade. Attack the enemies and try to knock the guns off their hands, as quickly as possible (in life-threatening situations, also use the smoke pellets). After you have cleared the upper level, jump down and deal with the rest of the bandits, who will not be too much of a challenge anymore.
After the fights finish, locate a small elevator adjacent to the building's external wall. Jump onto the catwalk and set the elevator into motion, by charging the generator with the shock gloves
Wait for the elevator to come down, turn towards the weakened fragment of the wall and spread the explosive gel here. After you detonate it, use the disruptor, which will disable the jamming device.
Return to the higher level and make it over to the balcony shown in screenshot 1. Open the reinforced door, select the Cryptographic Sequencer from the inventory and solve the hacking minigame, which will result in the determining of the password.