Author Topic: Can't detect my GSM network with newest phones.  (Read 58 times)

kycfeel

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Can't detect my GSM network with newest phones.
« on: December 04, 2017, 04:27:14 AM »
Hey guys.
I'm testing my Yate 6 based GSM network built with Raspberry pi and BladeRF x40.
and I think i can't detect my network with newest phones (iPhone 6s or higher).

My old iPhone 6, 5c, and Motorola MB860 can detect it, and connect to it very well.
But newest phones, like iPhone 6s, and iPhone 7 can't even detect my network on settings.
I'm not sure about newest Android phones cause i don't have any test devices right now.

I'm pretty sure that every iPhones released to market support GSM network connectivity. So definitely not the hardware problem.
Any of you experiencing same problem as mine? Need your help!

paulc

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Re: Can't detect my GSM network with newest phones.
« Reply #1 on: December 07, 2017, 12:19:21 PM »
It is important to know the following:
- Is the bladeRF frequency (auto)calibrated?
- Are you using the 850MHz band?
- What is the PLMN (MCC+MNC) of the IMSI
- What is the PLMN broadcasted by the BTS
- Where you are located geographically

At the whim of US operators Apple (and others) have introduced restrictions about which bands are available to which networks. In some conditions the phones may not list some or all cells in a band. This depend on the hardware version, iOs version, SIM and network identity. I am not sure but it's possible that geolocation may be taken into account as well.

The GSM850 / LTE band 5 is one of the bands affected since it's supposed to be used only in North America, South Korea, China and Australia. If you're located somewhere else or not having a matching IMSI the phone may not list cells or may behave erratically.

Try using one of the worldwide GSM bands - 900 or 1800. These are unlikely to be restricted.

kycfeel

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Re: Can't detect my GSM network with newest phones.
« Reply #2 on: December 11, 2017, 04:57:38 AM »
Hello. Thanks for the reply.

I live in South Korea, My test network is using 900 band with 001 MCC 01 MNC (Test Network), and my BladeRF is calibrated with factory settings.

Trying to use 1800 band instead of 900, or Reset iPhone's network settings doesn't helped me. Still can't figure out what is the problem.

Anything that i can try more?