iPhone 13 (iOS 18.6.2) cannot detect 5G SA cell on Open5GS

[thisisbaskara]

Hi all,

I’m testing a Private 5G SA setup and facing an issue with iPhone 13.
Device: iPhone 13 (iOS 18.6.2)
Core: Open5GS
gNB: srsRAN and Baicells Aurora 243
USIM: Sysmocom SJA5 (PLMN 999/70)

Problem:
Android devices can detect and register to the 5G SA network without issues.
iPhone 13 cannot detect the 5G SA cell at all (only LTE is shown).

Expected behavior:
iPhone 13 should be able to detect and at least attempt registration on the 5G SA cell, same as Android UEs.

Questions:
Is this a limitation with Apple’s carrier bundle (MCC/MNC 999/70 not whitelisted)?
Has anyone successfully tested iPhone 13 (or newer, iOS 18.x) on Open5GS SA?
Any known workaround?

Thanks in advance for your guidance.

[gustavobsch]

Did you check this discussion ?
#248

[pahowart]

Unfortunately you are unlikely to get anything other than an iPhone 16 or greater to work outside of the USA on a private 5G network. The requirements in the Apple knowledge base article are correct with the exception of the iphone 13 through 15 support. You will find many threads on the issue but no response from Apple to clarify why device don't attach. I have confirmed with a spectrum analyser that the devices prior to iPhone 16 don't even attempt to initiate a radio link when a private 5G sim is used. It doesn't matter if you bought the device from Apple directly or from a carrier.

I can confirm that North American and European iPhone 16's will work perfectly with the Baicells 243 on N77 using open5gs and various other 5G cores. You should start with an iphone 16 to confirm you have the Core , Radio and SIM provisioned correctly then work from there to see if other versions will work.

[herlesupreeth]

The requirements in the Apple knowledge base article are correct with the exception of the iphone 13 through 15 support.

@pahowart I dont think this statement is correct since I own a iPhone 13 pro and it works with 5G private network.

[pahowart]

The requirements in the Apple knowledge base article are correct with the exception of the iphone 13 through 15 support.

@pahowart I dont think this statement is correct since I own a iPhone 13 pro and it works with 5G private network.

I hope that I am wrong but I have tested multiple 13's 14's and 15's on PLMN 99970 and none of them will attempt to attach using Private 5G on N77. These are devices purchased directly from Apple in Canada. iPhones 16's work instantly and are very stable on the network. I have tested using Open5GS and two commercial 5G cores. The devices all say they support N77 but who knows what is happening under the covers.

[herlesupreeth]

@pahowart can you please try Band 41 just in case it works?

[pahowart]

I don't have access to an SDR in our lab to change the band but I did some further digging and found out the issue. In summary, Canada didn't use the same Band plan for N77 as the USA. Therefore device manufacture had to block the upper part of N77 on devices shipped to Canada prior to the auction of 3800Mhz. The device specs show N77 support but the end user has no way of knowing that it is not the full band.

Below is the link to 3GPP document descibing the issue, but not sure link will work. You can search for the document titled: Report of [AT117-e][061][NR17] n77 variants (Bell Mobility) . It was part of the 3GPP TSG-RAN WG2 agenda on 03 March 2022.

https://www.3gpp.org/ftp/tsg_ran/WG2_RL2/TSGR2_117-e/Inbox/Drafts/%5BOffline-061%5D%5BNR17%5D%20n77%20variants%20(Bell%20Mobility)/R2-22xxxxx%20Summary%20of%20%5BAT117-e%5D%5B061%5D%5BNR17%5D%20n77%20variants%20(Bell%20Mobility)_v12_CATT.docx

I am sure this issue impacts other countries as well and might explain why some devices work and others don't. My guess is that a US or European iPhone 13 would likely work on Private 5G in Canada.

[ozankaraali]

Just to report, my iPhone 14 Pro Max (EU) attaches correctly in n77.

[pahowart]

@ozankaraali , Thanks for confirming EU version works. I have a NA iPhone 13, 14 Plus, and a 15 all purchased in Canada that will not attempt to attach. I was perhaps to pessimistic in my initial reply but up until I found the 3GPP document yesterday I didn't understand why Canadian variants pre 2024 don't work. At least we now know that Apple has made country specific firmware variants that aren't documented which partially explains why some people are successful and others struggle.

[qmodem-tech]

Which plmn id is flashed on SIM card which you are using in iPhone ?

[pahowart]

Which plmn id is flashed on SIM card which you are using in iPhone ?

I use 99970 with SUCI enabled. Works well on iPhone 16 Canadian variant. Have tested with physical and eSIM.

[gustavobsch]

@pahowart Would using band 41 help in your case? I understand you don't have an SDR

[pahowart]

@pahowart Would using band 41 help in your case? I understand you don't have an SDR

N41 TDD 2500Mhz should work in Canada using 5GNR. Canada didn't align with the US for B41 FDD. Canada used B7 for FDD on 2500Mhz, UL 2500 – 2570, DL 2620 – 2690.

Typically any 4G device from the US will work in Canada. With 5G devices, manufactures started to carrier config lock 5GNR to specific PLMN's that are not available for private networks in Canada. N77 was the first time that I realised manufactures are locking devices to a specific subset of the frequency band.

[thisisbaskara]

Did you check this discussion ? #248

yes, i already set the SIM Card, based on the guidance. I use sysmocom SJA5