UEsim LTE SG SMS

 

This tutorial willl show how to send SMS over SG from Amari UEsim. Overall procedure in protocol sequence is same as in the tutorial LTE SG SMS with Commercial phone. This tutorial is mainly to show a UEsim operation procedure.

In 2G/3G, SMS is supported via CS (Circuit Switch) network, but in LTE we need different mechanism for SMS since LTE is PS (Packet Switch) only (not supporting CS). Those new mechanism for SMS in LTE are as follows :

• SMS over SG interface : This is to send / receive SMS over NAS message. This is called SG SMS
• SMS over IMS : This is to send / receive through IMS. (For this, check out this tutorial)

NOTE : For some additional / summarized tips on SG SMS testing, refer to this wiki.

NOTE :  UEsim does not support IMS based SMS.

 

 

Table of Contents

• UEsim LTE SG SMS
• Test Setup
• Key Configuration Parameters
• Configuration
• Perform the test
• Log Analysis

 

 

Test Setup

Test setup for this tutorial is as shown below.  

• SIM Card used in this tutorial is the one delivered with the system as it is.
• If you want to change the configuration, The tutorial Configuration Guide would help

 

 

Key Configuration Parameters

Followings are important configuration parameters for this tutorial. You may click on the items for the descriptions from Amarisoft documents.

• UEsim
• sms

 

Configuration

I used the ue.default.cfg (LTE default configuration) as it is on UE sim without changing any contents in it.

I used the enb.default.cfg (LTE default configuration) as it is on Callbox without changing any contents in it.

I used the mme-ims.cfg (mme default configuration) as it is on Callbox without changing any contents in it.

In the mme-ims.cfg, you would notice that ue_db-ims.cfg is used for UE db on Callbox.

In this tutorial, following SIM information will be used within ue_db-ims.cfg. Make it sure to configure the same parameters on UE side as well.  Here pay special attention to 'tel' numbers in impu configuration because you need to use the numbers as destination number when you send SMS from UEsim.

In ue.default.config on UEsim, Make it sure that imsi and K value in this file matches the value on enb side shown in previous slide

Following is the configuration on Callbox (enb.default.cfg). These configurations (N_RB_DL, N_ANTENNA_DL, TDD etc) are not important. You can specify these in any way as long as there is no problem with the initial attach process.

Following is the configuration on UE sim (ue.default.cfg). These configurations (CELL_BANDWIDTH, N_ANTENNA_DL, TDD etc) are not important either. You can specify these in any way as long as there is no problem with the initial attach process.

NOTE : In commercialized UE(like mobile phone), you would not configure these on your UE because the UE would figure out all these configuration automatically. But UE sim does not support frequency scanning. So you need to manually configure these settings in configuration file

 

Perform the test

Start trace logging on Callbox

Power on UE on UE sim

If UE successfully detect the cell, it will print out following message 'Cell n: SIB found'

Then you see following traces on Callbox and confirm UE gets attached

When UE is in connection with a cell, you can get the information on the connected cell using 'cells' command

When UE is in connection with a cell, you can get the information on the connected UE using 'ue' command in (ue) screen on UE Sim. Pay attention to UE_ID shown here since you need to use it when you send SMS.

When UE is in connection with a cell, you can get the information on the connected UE in NAS layer using 'ue' command in (mme) screen. Make it sure that the UE is assigned with at least one IP address.

Send a SMS using sms command as shown below. Here you see UE_ID confirmed on UEsim and tel number configured in impu parameter are used as the source and desgination of the sms message.

NOTE : You can send SMS from UEsim using RemoteAPI if you want. Following is an example of sending SMS using RemoteAPI.

 

Log Analysis

Connect all the components related to SMS analysis. Here you see MME, ENB, IMS are connected. It is important to collect IMS for sms since IMS works as SMS center in Amarisoft.

Enable all the components in MME. If you click on [+] icon at the bottom of the dialog box, it will collect all of the layers with debug mode (i.e, collecting the most detailed information).

Enable all the components in IMS. If you click on [+] icon at the bottom of the dialog box, it will collect all of the layers with debug mode (i.e, collecting the most detailed information).

Filter NAS/IMS for easy analysis. This is just to make it easier to analyze the log for SMS since SG SMS related information is being carried by IMS and NAS message.

For every sms sent, you would get a sequence of messages as highlighted below. SMS contents over SG are received and processed by IMS layer and the contents are exchanged between UE and SMS Center (IMS in this case) via Over The Air (OTA) message (NAS in this case).

In Amarisoft log, NAS message does not show the decoded SMS contents. If you want to check out the contents of SMS, you should check IMS log labeled as 'SMS'.