AT+QNWLOCK="common/lte" explained and question

IoT Modules LTE Standard Module
1

Hi
I’m currently working with your modules (EC25) and have a couple of questions about the AT+QNWLOCK="common/lte" command. I’d appreciate your expertise in clarifying a few things

  1. AT+QNWLOCK=“common/lte”: Could you explain exactly how the AT+QNWLOCK="common/lte" command works in terms of cell selection? I know how to use it, but I would like to know does it lock the device to the selected cell tower and ignore ping requests from other cell towers, or does it still accept and process requests from other networks in the background?

  2. Make it persistent, is there a way to make the cell-locking setting persistent even after a power cycle (power off/on)? I want to ensure that the device remains locked to the LTE network without needing to reconfigure it after every reboot.

Thank you for your help!

2

Dear customer,
1, Every cell has a PCI(physical cell ID) and working with a specified frequency. This command force module working on a specified frequency or/and lock to cell with a specified physical ID. It won’t received message of other cell if execute this command to lock frequency and PCI.
2, If you want to lock module on LTE network, it is better to lock module on specified RAT mode. Below command will make module to search LTE network only.
AT+QCFG=“nwscanmode”,3,1

3

Hi,

Thank you for answer. Ok so this confirm that AT+QNWLOCK to a selected cell-id and earfcn will make all requests from other LTE cell towers will be discarded/not answered right?

Sorry i mistyped the 2nd question, i would like to know if it is possible to make QNWLOCK to a EARFCN and PCI persistent across reboot. if yes how to do it please.

4

No, the setting will be reset after reboot.

5

Hi again,

I forgot to add an other question, does locking to a selected PCI and EARFCN with AT+QNWLOCK prevent the device from searching in background other cell towers?

6

Hello (again again),

I locked my device to a PCI and EARFCN correctly, when I type AT+QENG=“servingcell” it display the correct cell tower I locked to with the correct PCI and EARFCN. However I can still type AT+QOPS (with AT+QOPSCFG=“scancontrol”,2) and I still get results of other LTE cell tower than the one I am locked to. How come the device can find other cell tower if I am locked to an other LTE cell tower with AT+QNWLOCK. Now my question is:

When I lock to PCI and EARFCN with AT+QNWLOCK does it stop device from searching other network/cell tower in background?

Why when locked to PCI and EARFCN with AT+QNWLOCK I can still search other LTE cell tower with AT+QOPS?

7

Hi,
May I know your applicaiton scenario?
AT+COPS? will force module to search all avaiable cell. But modem won’t attach to. It is different things.

8

Hello, the application scenario was no SIM inserted inside the device, PPP interface was not connected to network. I was locked to an LTE celltower I choosed with AT+QNWLOCK.

AT+QOPS scan were made without PPP interface being connected.

When I am locked to PCI and EARFCN with AT+QNWLOCK will it prevent device from scanning available cell in background? If device keep searching available cell tower in background even if I am locked to PCI and EARFCN, how to disable background network scanning?

9

Hello again,

I saw on your answer you mention AT+COPS for searching available cell, but I used AT+QOPS.

10

Hi,
It has the similar functon. The Command at+qops lists the available network information of
operators for all neighbor cell.

11

I am confused why you hope to disable the scaning of other celltower or band? It may cause unstable network connection.

12

Hello,

I am doing test in my homemade LTE/4G test lab. Do not worry, it is only for testing and learning purpose. I study radiofrequency and network at school.

1) Can you answer me, when connected to PPP interface and registered to network, does locking to a celltower with AT+QNWLOCK disable background network scanning of other celltower or the device keep searching other celltower even if locked to one.

2) If device keep searching other celltower even when locked to EARFCN and PCI with AT+QNWLOCK, how to disable networking scanning?

I know AT+QCFG=“NWSCANMODEEX”, command can be used to configure network searching mode, but can it be used to disable network scanning?

13
  1. Yes, it will continue to scan or search. But modem won’t attach to other frequency.
  2. There is no command to disable scaning for parts of network/cell.
14

Hello.

Ok, I understand. Thanks for explanation.

  1. When locking the device to LTE band7 with AT+QCFG=“band”,1,40,0 will all network scan or search functionality be effectively locked to that specific band, or is it still possible for the device to scan and display available networks outside the locked band?

  2. When using AT+QCFG=“nwscanmodeex”,16 and AT+QCFG=“nwscanmode”,3,1 it will make the device only working in LTE mode and scan/search of network only in LTE right? Does these command prevent downgrade? For example the device wanting to switch from LTE to 3G, from LTE to 2G etc.

15

1, It will still scan other band. But it won’t attach to other band.
2, It will search LTE network only. Network won’t switch from LTE to 2G/3G in such situation.