LTE Dual SIM
The purpose of this tutorial is to show you how to configure and perform Dual SIM test with LTE network.
DualSIM technology allows a mobile device to support two SIM cards simultaneously. This means the device can manage two different mobile network services at the same time, without the need for carrying two separate phones.
There are mainly two types - DualSIM Standby (DSDS) and DualSIM Dual Active (DSDA).
- DualSIM Standby (DSDS): In this mode, while one SIM card is active for calls or data use, the other becomes inactive.
- DualSIM Dual Active (DSDA): Both SIMs can be active at the same time. This means you can receive calls on one SIM while talking on the other.
Table of Contents
- LTE Dual SIM
Test Setup
In this tutorial, you may use two types of as shown below. All the components will launch automatically by lte service and all the components will be automatically added to 'screen' window as well.
Test 1 - DSDS MT Voice Call
In this test, I will show you how to make a MT voice call (VoLTE) to each of SIM on DSDS(Dual Sim, Dual Standby) UE.
Configuration
Regarding the details of the configuration (i.e, how to apply each of the configuration file to each of the network component or key parameters in each configuration file), refer to this tutorial. In this tutorial, I would only provide the list of the configuration files.
- gnb-sa-2-plmn_DualSim_DSDS.cfg
- ims.default-0_DualSim_DSDS.cfg
- ims.default-1_DualSim_DSDS.cfg
- mme-ims-0_DualSim_DSDS.cfg
- mme-ims-1_DualSim_DSDS.cfg
- ue_db-ims-dsds-0_DualSim_DSDS.cfg
- ue_db-ims-dsds-1_DualSim_DSDS.cfg
- ots-multi-mme_DualSim_DSDS.cfg
Perform the test
First check out on UE and make it sure that Two SIMs are configured and enabled.
Then start the callbox and power on (Airplane mode off) the UE. (
Wait until the initial attach is complete. In case of the UE supporting DualSIM, it is expected that both of the two USIMs perform the initial attach procedure. Once the initial attach is complete,
Check out the registered UE on the first IMS server and make it sure that one of the USIM is registered. In this test, the USIM with IMSI 001010123456789 is registered.
Check out the registered UE on the second IMS server and make it sure that the other USIM is registered. In this test, the USIM with IMSI 001010123456780 is registered.
Then make a MT call from the first IMS server to the USIM with IMSI 001010123456789.
Then you should see the call is coming to [1]USIM (the USIM registered to the first IMS server).
Now make a MT call from the second IMS server to the USIM with IMSI 001010123456780.
Then you should see the call is coming to [2]USIM (the USIM registered to the second IMS server).
Log Analysis
First confirm that the SIB1 of Cell 1 is broadcasting as intended. In this test, it broadcast the PLMN 001-01.
First confirm that the SIB1 of Cell 2 is broadcasting as intended. In this test, it broadcast the PLMN 460-02.
When power ON the UE that supports DUAL SIM, one of the SIM camp on to one of the cell. In this case, one UE camps onto the cell with PLMN 460-02 (Cell 2).
Then the other SIM camp on to the other cell. In this case, the other UE camps onto the cell with PLMN 001-01(Cell 1).
Once the initial registration is done, one of the USIM completes IMS Registration.
Then, the remaining USIM completes IMS Registration as well.
When make an MT call to 001010123456789, you get the IMS/SIP sequence for VoLTE call setup as shown below.
When make an MT call to 001010123456780, you get the IMS/SIP sequence for VoLTE call setup as shown below.
Test 2 - DSDS MO Voice Call
In this test, I will show you how to make a MO voice call (VoLTE) from one of SIM on DSDS(Dual Sim, Dual Standby) UE.
Configuration
The configuration for this test is same as the configuration in previous test (Test 1).
Perform the test
USIM settings and initial attach process for this test is same as the operations in previous test(Test 1). It is assumed that you get both USIM successfully attached.
Once the initial attachment is complete, make a Call from one of your USIM (in this test I made the call from SIM1) to the loopback number set in the configuration file (666 in this test). And then make it sure that the call go through.
Log Analysis
Assuming that the initial attatchment is complete, the first thing you want to check is to ensure that SIM1 completes IMS registration
Ensure that SIM2 also completes the IMS registration.
When you make an MO voice call from one of the SIM (SIM1 in this case), you would see VoLTE setup signaling and RTP traffics.
Test 3 - Data Traffic during Voice Call
In this test, I will show you how to make a MO voice call (VoLTE) from one of SIM on DSDS(Dual Sim, Dual Standby) UE.
Configuration
The configuration for this test is same as the configuration in previous test (Test 1).
Perform the test
USIM settings and initial attach process for this test is same as the operations in previous test(Test 1). It is assumed that you get both USIM successfully attached.
Once the initial attachment is complete, make a Call from one of your USIM (in this test I made the call from SIM1) to the loopback number set in the configuration file (666 in this test). And then make it sure that the call go through.
While the voice call is going on with one SIM, generate an IP data traffic with another SIM and see if both of the traffic goes through.
This is not what is expected, but with the commercial UE that we used for the test it turned out that the IP data traffic pauses and resumes after the VoLTE call completed.
You will have similar result (i.e, paused packet traffic) with ping test as well.
