NR NPN (Non Public Network)
This tutorial is to show you how to configure and test NR NPN. NPN (Non Public Network) is another word for Private Network. We have used the term Private Network since long again from 4G but the implementation of Private Network hadn't clearly been defined in 3GPP. Recently (in 3GPP Release 16) this feature is formally defined / specified in 3GPP with the name of NPN (Non Public Network). Even though I would not say every detailed implementation of NPN is defined in 3GPP, roughtly 3 or 4 different high level architecture of the implementation are frequently mentioned in various documents. Followings are a list of common architectures of NPN implementation. As of now, Amarisoft product support [A],[B],[D].
- [A] SNPN (Standalone Non-Public Network)
- [B] PNI-NPN (Public Network Integrated Non-Public Network) with Shared RAN
- [C] PNI-NPN (Public Network Integrated Non-Public Network) with Shared RAN and Core Network CP
- [D] PNI-NPN (Public Network Integrated Non-Public Network) with Shared RAN and Core Network CP & UP
Table of Contents
- NR NPN (Non Public Network)
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.
- 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
If you have a commercial UE that support UE assistance information with Release Preference, you can use the Setup A. If you don't have any commercial UE supporting this feature but have Amarisoft UEsim you can use Setup B. In this Test, Setup B is used.
Setup A
This is the setup for the case where you use a commercial phone as DUT.
Setup B
This is the setup for the case where you use Amarisoft UEsim as DUT.
Key Configuration Parameters
Followings are important configuration parameters for this tutorial. You may click on the items for the descriptions from Amarisoft documents.
- cag_info_list : In this link, you can find the descriptions for all the parameters below.
- plmn
- cag_info
- network_name
- network_name
Test 1 : PNI-NPN Single Cell
This test show a test case where you configure PNI-NPN (Public Network Integrated Non-Public Network) in single cell and verify the operation.
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 gnb-sa-pni-npn-1.cfg which is copied and modified from gnb-sa.cfg on Callbox (gNB)
I am using mme-ims-pni-npn-1.cfg and ue_db-ims-pni-npn-1.cfg which are copied from mme-ims.cfg and ue_db-ims.cfg respectively.
On UEsim, I used ue-nr-sa-pni-npn-1.cfg which has been copied and modified from ue-nr-sa.cfg (
gnb-sa-pni-npn-1.cfg is configured as follows.
Configure network information for NPN which will be broadcast in SIB1 using cag_info_list parameter.
mme-ims-pni-npn-1.cfg is configured as shown below.
Specify the plmn to which UE is supposed to camp on and enable NPN support by setting cag_supported : true. Then include a ue_db that carries the cag_info_list.
ue_db-ims-pni-npn-1.cfg is configured as shown below.
In the ue_db, there should be at least one item that should match the plmn specified in enb.cfg and mme.cfg.
{plmn: "00104", cag_id_list: [7, 80, 90], cag_only_ind: true}
{plmn: "00104", cag_id_list: [80,7, 90], cag_only_ind: true}
{plmn: "00104", cag_id_list: [80,90, 7], cag_only_ind: true}
ue-nr-sa-pni-npn-1.cfg is configured as shown below.
The ue in the ue_list should carry a cag_info_list that match the camping cag specified in callbox (enb.cfg and mme.cfg) and set as_release to 16 or higher (
Perform the Test
Run lte service on callbox and check 'cell' command. You would notice the multiple PLMNs you configured in enb.cfg as shown below. Note that the plmn in cell command output shows all the plmns specified in cell configuration.
Check which PLMN is connected to AMF as shown below. If DUT try to attach to different PLMN from the one shown below, it will be rejected by core network (AMF).
Now start trace logging.
Power on UE on UEsim (If your DUT is a commercial phone, turn on the phone)
Wait until the DUT complete the initial attach. If UE successfully camp onto the cell, you may assume that NPN works but the details should be verified from the captured log. Not much details in the trace log shown here.
Log Analysis
Following is the log snapshot that are involved in UE assistance information message and handling process.
Make if NG setup process is properly completed with NGAP log. Here you see gNB notifies plmn 001-01 as globalGNB-ID and notifies 001-01,001-04,001-05 as broadcast PLMNs.
Then confirm that the plmn-IdentityInfoList and npn-IdentityInfoList in SIB1 is broadcast as configured in enb.cnf.
Here you see PLMN 001-01 is broadcast in plmn-IdentityInfoList and in npn-IdentityInfoList.
Here you see PLMN 001-04 and 001-05 are listed in npn-IdentityInfoList as specified in enb.cfg
When UE camp on, it notifies that the CAG plmn it selected via selectedPLMN-Identity IE in RRC setup Complete message.
Based on the cag plmn selection from the UE, gNB notifies about the selected cag information to core network via pNI-NPN-Access-Information IE in NGAP message (Initial UE message).
Then Network notifies the attached PLMN back to UE via 5G-GUTI in Registration Accept message.
Core Network notifies gNB of all the plmn as associated cag id list via allowed-PNI-NPI-List in the NGAP message Initial Context Setup Message. The information in this list is configured by cag_info_list specified in ue_db.
RRC / NAS Signaling
SIB1 (SA)
: This is SIB1 containing npn configurations
{
message c1: systemInformationBlockType1: {
cellSelectionInfo {
...
},
cellAccessRelatedInfo {
plmn-IdentityInfoList {
{
plmn-IdentityList {
{
mcc {
0,
0,
1
},
mnc {
0,
1
}
}
},
trackingAreaCode '000000'H,
cellIdentity '001234501'H,
cellReservedForOperatorUse notReserved
}
},
cellReservedForOtherUse true,
npn-IdentityInfoList-r16 {
{
npn-IdentityList-r16 {
pni-npn-r16: {
plmn-Identity-r16 {
mcc {
0,
0,
1
},
mnc {
0,
1
}
},
cag-IdentityList-r16 {
{
cag-Identity-r16 '00000001'H
},
{
cag-Identity-r16 '00000002'H
},
{
cag-Identity-r16 '00000003'H
},
{
cag-Identity-r16 '00000004'H
}
}
}
},
trackingAreaCode-r16 '000000'H,
cellIdentity-r16 '001234501'H,
cellReservedForOperatorUse-r16 reserved
},
{
npn-IdentityList-r16 {
pni-npn-r16: {
plmn-Identity-r16 {
mcc {
0,
0,
1
},
mnc {
0,
4
}
},
cag-IdentityList-r16 {
{
cag-Identity-r16 '00000007'H
},
{
cag-Identity-r16 '00000008'H
},
{
cag-Identity-r16 '00000009'H
}
}
},
pni-npn-r16: {
plmn-Identity-r16 {
mcc {
0,
0,
1
},
mnc {
0,
5
}
},
cag-IdentityList-r16 {
{
cag-Identity-r16 '00000002'H
},
{
cag-Identity-r16 '00000200'H
}
}
}
},
trackingAreaCode-r16 '000001'H,
cellIdentity-r16 '001234501'H,
cellReservedForOperatorUse-r16 reserved
}
}
},
connEstFailureControl {
...
},
servingCellConfigCommon {
...
},
ue-TimersAndConstants {
...
}
}
}
RrcSetupComplete (SA)
: This is RrcSetupComplte message showing the cag plmn that UE selected
{
message c1: rrcSetupComplete: {
rrc-TransactionIdentifier 0,
criticalExtensions rrcSetupComplete: {
selectedPLMN-Identity 5,
dedicatedNAS-Message '7E004179000D0100F110F0FF000010325476982E02E0E0'H,
nonCriticalExtension {
nonCriticalExtension {
ul-RRC-Segmentation-r16 true
}
}
}
}
}