If you have an issue with poor battery life, data connections, making/receiving calls or texts you might want to look into this....
I got an iPhone 5 recently and switched to 3 network in the UK. I keep having problems all day at work with the network and I can't access data, make or receive calls, or send/receive texts with 4 or 5 bars. Someone else here has exactly the same problem with an iPhone 5 (bought from a different shop on a different day, and a different colour, so unlikely to be the same batch), but the others with different model/manufacturers phones on the same network are fine. Anyone else experience similar?
I've tracked down the issue using Field Test mode (type in *3001#12345#*) and checking on the UMTS connection status under UMTS cell environment/UMTS RR Info. It seems as soon as the iPhone hands over to a particular Cell ID it's useless. I've spoken to Three and they say there's nothing wrong with that cell and can see the number of calls an hour and data useage going through it. They said that sometimes iPhones seem a bit more "jumpy" when I explained it to them. If I turn off the phone and turn it on it registers to a different cell ID, then after a short time does a FACH/handover to the cell in question, then never makes it to PCH or DCH, it just ends up with no RRC status and then goes between Connecting and Disconnecting. As a result it also munches through loads of battery trying to connect to that cell and failing all day. All the meantime it has great signal strength supposedly. It's about -70 dBm or higher. I can see the big cell tower out the window which has 4 cells belonging to Three, pointing in different directions on it, and this area is supposed to have good three coverage including indoors!
When checking Field Test mode of the others (non-apple) phones on the same network they never use the Cell ID that doesn't work. The other person here with an iPhone 5 does exactly the same as mine. Occasionally a few times a day it will briefly hand over to a different Cell ID and I'll get a flood of texts and emails. If I reboot the phone it will also register to a different Cell ID, I'll then have maybe a minute it'll work fine, then do a handover to the cell that doesn't work here, but apparently functions fine for other people within range, or doesn't get used by other model phones who work here.
Being an RF test engineer I've set up an RF signal generator on that cell frequency and jammed that cell around my desk. The iPhone then registers to a different Cell ID and then works perfectly fine ALL DAY! So why do our iPhones connected to this problem cell where we are, and no-one elses phones do?
I can't spend 5 days a week with 'great coverage' but unable to use my phone about 97% of the day, and I can't use test equipment to jam a certain UMTS cell every day that all the non-iPhone users phones automatically choose not to use! I can't even use Siri to set a reminder!!!
As mentioned there's supposedly nothing inherently wrong with that Three cell, but in my work no-one elses phone chooses it (so maybe it's fine, but poor in this area so the phone should choose a different one). It doesn't work from here to another 1/2 mile up the road. If I walk to the bottom of the hill (500 yards?) where the tower is it doesn't work all the way there, then when I get next to it does a cell handover (FACH), then straight to DCH or PCH. So there is obviously some inherent problem with our iPhones and the cell selection in this area.
I can send my iPhone back, but there's nothing to say I won't get exactly the same problem if I get an iPhone 5 on a different network as there's also other providers all working of the same mast, so may have a similar issue, if not here, somewhere else.
Anyone else having this issue? If in doubt and you supposedly have great sognal strength but can't even send a text have a look in field service mode and look at the RRC status. If it's Cell_PCH or Cell_DCH then it should be fine (PCH being connected idle waiting to receive calls, and DCH meaning a current data channel is set up and running). If it says nothing or keeps being stuck on FACH or disconnected/connecting, then you've got the same cell connectivity issue as me.
I hoped 6.0.1 that's supposed to "fix Celluar and WiFi connection issues" might be the cure, but it's exactly the same. I'm unsure if this issue is with iPhone 5s or iOS 6. Unfortunately the SIM's a different shape, else I'd try my old 3GS.