Amarisoft

LTE NB NTN (Non Terrestrial Network)

 

This tutorial is to show you how to configure and test LTE NB NTN.  NTN (Non Terrestrial Network) is a type of network deployment in which some type of non-terrestrial (e.g, satellite or other airborne component).  Overall protocol sequence of NTN is not much different from the existing LTE RAN access (LTE NB, LTE, NR), but one major difference is to handle the long propagation delay between the ground components (eNB and/or DUT) and Satellite. There are two major components introduced in 3GPP as listed below.

NOTE : This tutorial is only for  LTE NB  based NTN. For NR based NTN, refer to this note.

 

There are various different type of NTN deployment in  3GPP TR 36.763. Currently Amarisoft NTN implementation is as shown below.

LTE NB NTN Overview 01

 

NOTE : The configuration in this tutorial is based on the release 2023-04-21. It is strongly recommended to upgrade your callbox to the release equal to or later than this release.

 

 

Table of Contents

 

 

Test Setup

 

Test setup for this tutorial is as shown below.  This is just for low layer testing, you may not need any complicated IP layer setup.

With Amarisoft eNB and UEsim, we can try with following two different setups.

 

TestSetup Callbox NTN 01

 

 

Key Configuration Parameters

 

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

 

 

 

Test 1 : NTN with Simulated GEO and UEsim

 

Configuration

 

The configuration shown here is common configuration for all the subtests belonging to Test 1 and I will not show this configuration repeatedly for every subtest.

I have used enb-nbiot-ntn.cfg which is included in the installation package from the release 2023-04-21.

LTE NB NTN Test 1 Config 01

I am using mme-ims.cfg and ue_db-ims.cfg  as they are.

LTE NB NTN Test 1 Config 02

On UEsim, I used ue-nbiot-ntn.cfg which is included in the installation package from the release 2023-04-21. (NOTE : If you are using the commercial UE as a DUT, you don't need this step. Just make it sure that your UE support UE-assistance-information for release-preference).

LTE NB NTN Test 1 Config 03

 

enb-nbiot-ntn.cfg  is configured as follows.

LTE NB NTN Test 1 Config 04

LTE NB NTN Test 1 Config 05

LTE NB NTN Test 1 Config 06

LTE NB NTN Test 1 Config 07

LTE NB NTN Test 1 Config 08

 

mme-ims.cfg is configured as follows :

LTE NB NTN Test 1 Config 09

 

ue-nbiot-ntn.cfg  is configured as shown below. (NOTE : If you are using the commercial UE as a DUT, you don't need this step. Just make it sure that your UE support UE-assistance-information for release-preference).

LTE NB NTN Test 1 Config 10

LTE NB NTN Test 1 Config 11

 

 

Perform the Test

 

Run lte service on callbox and check 'cell' command.

LTE NB NTN Test 1 Run 01

This is not the mandatory process.. but I did this to collect SIB message in the log for a few seconds at the beginning. I did bcch=1 and after a few seconds did bcch=0.

LTE NB NTN Test 1 Run 02

Now start trace logging.

LTE NB NTN Test 1 Run 03

Power on UE on UEsim (If your DUT is a commercial phone, turn on the phone)

LTE NB NTN Test 1 Run 04

Wait until the DUT complete the initial attach.

LTE NB NTN Test 1 Run 05

 

 

Log Analysis

 

Following is the log snapshot that are involved in communication with NTN.

Sample Log

LTE NB NTN Test 1 Log 01

LTE NB NTN Test 1 Log 02

LTE NB NTN Test 1 Log 03

LTE NB NTN Test 1 Log 04

LTE NB NTN Test 1 Log 05

LTE NB NTN Test 1 Log 06

LTE NB NTN Test 1 Log 07

LTE NB NTN Test 1 Log 08

 

 

 

Test 2 : NTN with Simulated GEO and Commercial UE in non-NTN band

 

This test is with a commercial UE from Quectel: BG770-GL-TE-A. Quectel support was needed for NTN upgrade

 

Configuration

The configuration shown here is common configuration for all the subtests belonging to Test 1 and I will not show this configuration repeatedly for every subtest.

I have used enb-nbiot-ntn-Quectel.cfg

LTE NB NTN Test 2 Config 01

I am using mme-ims.cfg and ue_db-ims.cfg  as they are.

LTE NB NTN Test 2 Config 02

 

enb-nbiot-ntn-Quectel.cfg  is configured as follows.

LTE NB NTN Test 2 Config 03

LTE NB NTN Test 2 Config 04

LTE NB NTN Test 2 Config 05

LTE NB NTN Test 2 Config 06

LTE NB NTN Test 2 Config 07

LTE NB NTN Test 2 Config 08

LTE NB NTN Test 2 Config 09

 

 

Perform the Test

Run lte service on callbox and check 'cell' command.

LTE NB NTN Test 2 Run 01

This is not the mandatory process.. but I did this to collect SIB message in the log for a few seconds at the beginning. I did bcch=1 and after a few seconds did bcch=0.

LTE NB NTN Test 1 Run 02

Now start trace logging.

LTE NB NTN Test 1 Run 03

Configure on DUT side and power it on.

LTE NB NTN Test 2 Run 04

Wait until the DUT complete the initial attach.

LTE NB NTN Test 2 Run 05

 

 

 

Log Analysis

Following is the log snapshot that are involved in communication with NTN.

Sample Log

LTE NB NTN Test 2 Log 01

LTE NB NTN Test 2 Log 02

LTE NB NTN Test 2 Log 03

LTE NB NTN Test 2 Log 04

LTE NB NTN Test 2 Log 05

 

 

 

Test 3 : NTN with Simulated GEO and Commercial UE in NTN band

 

This test is with a commercial UE from Quectel: CC660D-LS

 

Device Info

The information of the specific device and firmware information that was used in this test is as follows :

Quectel CC660D-LS

 

Firmware version:

    Quectel_Ltd

    Quectel_CC660D-LS

    Revision: CC660DLSAAR01A02

 

 

Configuration

The configuration shown here is common configuration for all the subtests belonging to Test 1 and I will not show this configuration repeatedly for every subtest.

I have used enb-nbiot-ntn-geo-CC660D.cfg

LTE NB NTN Test 3 Config 01

I am using mme-ims.cfg and ue_db-ims.cfg  as they are.

LTE NB NTN Test 2 Config 02

 

enb-nbiot-ntn-geo-CC660D.cfg is configured as follows.

LTE NB NTN Test 3 Config 03

LTE NB NTN Test 3 Config 04

LTE NB NTN Test 3 Config 05

LTE NB NTN Test 3 Config 06

LTE NB NTN Test 3 Config 07

LTE NB NTN Test 3 Config 08

 

 

Perform the Test

This is not the mandatory process.. but I did this to collect SIB message in the log for a few seconds at the beginning. I did bcch=1 and after a few seconds did bcch=0.

LTE NB NTN Test 1 Run 02

Now start trace logging.

LTE NB NTN Test 1 Run 03

Configure on DUT side and power it on.

AT+QGNSSINFO=43.295,5.373,20,0,100

 

+QGNSSINFO: 1

 

at+cgact=1,1

AT+QGNSSINFO=43.295,5.373,20,0,100

 

OK

+QGNSSINFO: 0

 

at+cfun=1

OK

 

at+cgact=1,1

 

+CEREG: 1,"0002","01A2D101",9,0,0,"11100000","11100000"

at+cgact=1,1

 

+IP: 192.168.2.2

Wait until the DUT complete the initial attach.

LTE NB NTN Test 3 Run 01

 

 

Log Analysis

Following is the log snapshot that are involved in communication with NTN.

Sample Log

LTE NB NTN Test 3 Log 01

LTE NB NTN Test 3 Log 02

LTE NB NTN Test 3 Log 03

LTE NB NTN Test 3 Log 04

LTE NB NTN Test 3 Log 05

LTE NB NTN Test 3 Log 06

LTE NB NTN Test 3 Log 07

LTE NB NTN Test 3 Log 08

LTE NB NTN Test 3 Log 09

 

 

 

RRC / NAS Signaling

 

SIB31 (LTE)

: This is SIB31 containing ephemeris

{

  message c1: systemInformation-r13: {

    criticalExtensions systemInformation-r13: {

      sib-TypeAndInfo-r13 {

        sib31-v1700: {

          servingSatelliteInfo-r17 {

            ephemerisInfo-r17 orbitalParameters: {

              semiMajorAxis-r17 8394210402,

              eccentricity-r17 0,

              periapsis-r17 0,

              longitude-r17 242097885,

              inclination-r17 0,

              anomaly-r17 177192

            },

            nta-CommonParameters-17 {

              nta-Common-r17 7776350

            },

            ul-SyncValidityDuration-r17 s240,

            k-Offset-r17 1023

          }

        }

      }

    }

  }

}

 

 

 

 

FAQ

 

I am putting a list of frequently asked questions and answers that would help everybody.

 

[Q1] why we need channel simulator ?

[A1] It is necessary to simulate the constantly changing real time position of the satellite

 

[Q2] do we always need to use the channel simulator ?

[A2] Yes for MEO or LEO in which delay and doppler varies relatively in large scale. Maybe optional to GEO in which delay and doppler does not vary widely. (NOTE : You may use the internal channel simulator at the testing phase in quick and easy way, but you can also use an external satellite channel simulator as well).

 

[Q3] What is the maximum delay simulated by Amarisoft Channel Simulator ?

[A3] Up to several seconds. The maximum value will depend on the sample rate, the value is max_delay in s = 2.147e9 / (sample_rate in Hz). In NB-IoT, for example, the sample rate is usually 1.92 MHz, so the max_delay is around 1118 seconds.

 

[Q4] What is the minimum configurable altitude of a satellite ?

[A4] The 3GPP encoding for the semi-major axis has a minimum of 6500 km, so a minimum of 122(=6500-6378) km altitude, where 6378 is the radius of the earth

 

[Q5] For ue_position, ground_position, we allow the altitude with the range of -1000m to 20km, what is the reason to allow negative values ?

[A5] It is to configure altitude below sea level. (https://en.wikipedia.org/wiki/List_of_places_on_land_with_elevations_below_sea_level )