Please, in one case reported by one friend they are having HO Failure from Huawei to Nokia in a new Nokia network.
The cause that I found via Wireshark analyses is cell-not-available in the radio network message.
I checked in the 3gpp document TS136 413, and I found the reason, but neither explanation nor description.
Please can you support and share your findings.
It is a typical case of IOT, I have participate some years ago.
In one IOT, we make the handover test with NSN eNB, but it fails.
From the signalling caught by EPC side, in the handover failure message, the cause is “Cell Not Available” (cell-not-available).
The, we looked for some handover configuration error.
For handover, we need to configure the Neighbor cell configuration and Neighbor relation configuration.
To let the handover happen successfully we need to know the information of neighbor cell as the following picture.
(ENB ID, Cell ID, PCI, TAC and so on)
Also, the information of our eNB and the neighbor cell that customer offer are as bellow.
The information for our eNB:
The information for Neighbor cell:
From the two tables, we can see that the eNB ID, PCI and TAC is clear but except Cell ID.
In the first table, we think that “InCelId” is cell id, the same value as PCI and we configure like this.
But the handover fails this time.
So we have a doubt that “InCellId” is not cell id.
In the table there is another item “eutraCelld”, the customer tell us this item is from “eNB ID+ Cell ID”, So we think the real Cell ID should contained in this item, but how can we get it?
The value of eutraCelld is a decimal number, we change it to a hexadecimal number.
For example, the cell of PCI 156, eutraCelld is 156429569, change to hexadecimal number is 952ED01, eNB ID is 611053, changes to hexadecimal number is 952ED, so Cell ID of this cell is 01, just is 1.
In the same way, Cell ID of PCI 157 is 2, Cell ID of PCI 158 is 3, Cell ID of PCI 177 is 1 and so on.
Like this we can get, the 3 cells in each eNB, the cell id is 1,2,3.
So we modify the cell id in Neighbor cell configuration, and test again.
From the signaling we can see, the handover success.
in LTE X2 Handover case, Cell-not-Available ( Reason value 10) can be reported as Failure reason for below two scenarios,
- X2AP Protocol. Messages: § HandoverPreparationFailure (0xC200) § HO Cancel (0xC001)
- S1AP Protocol. Messages: § PathSwitchRequestFailure (0x8203) § User Endset (UE) Context Release Request (0x8012)
Identify where you are failing from trace.