2G to 3G reselection delay

[mirc84]

Hello everyone,

I'm having some problems with reselection from 2g to 3g using Huawei Equip.
I have attached one excel with si2quater from 3 operators. for OP1 and OP2 the reselection takes very short while for OP3 takes very long.
Could you please give me an ideea?

For all teste I have used the same phone, Nokia C5.

Thank you for your time!

[tabordas]

Are the 3 operators using Huawei RAN? Is it 2G Huawei or 3G Huawei?

There are many variables such as:
. Number of defined 2G->3G neighbor relations. Depending on the IE included on the SI2Quater, you may need more than 1 SI2Quater to send all the neighbor list to the Ue.
. Number of 3G UARFCN.
. Feature activation: Huawei GBSS has a feature called Fast UMTS to GSM Cell Reselection at CS call release which automatically "forces" the reselection to 3G on call release. You may want to explore that. It works better on GBSS14. I know that other 2G vendors have similar features.
. Another possibility is to activate Blind Search where Ue reselects from 2G into 3G UARFCN. This minimizes the information sent to the Ue and therefore accelerates the reselection.

Hope it helps.

[mirc84]

Hey, thanks a lot! I might found the issue. Please see below, maybe it will help someone as I noticed there are a lot of irat reselection questions. :)

Only OP3 is Huawei. The rest are other vendors.


. Number of defined 2G->3G neighbor relations. Depending on the IE included on the SI2Quater, you may need more than 1 SI2Quater to send all the neighbor list to the Ue.
At a closer look I noticed that the message which contains the 3g PSC (on which the cell had to go) was sent by the network very late.
The reasons, at least from my point of view was:
- HW seems to send a 2qter message containing reselection information but no PSC (behavior different from other operators, see in the attachment). Is this ok from 3GPP point of view?
- there are 20 nbrs defined so they are split into more 2qter messages.

Regarding optimisation of 2qter message I found two parameters in GBSS14:
- SI 2quater IE Downsizing Switch (LST GCELLCCUTRANSYS).
- SI 2quater Optimization Switch (LST GCELLCCUTRANSYS)


. Number of 3G UARFCN.
:) see above. :)


. Feature activation: Huawei GBSS has a feature called Fast UMTS to GSM Cell Reselection at CS call release which automatically "forces" the reselection to 3G on call release. You may want to explore that. It works better on GBSS14. I know that other 2G vendors have similar features.
Do you have any ideea if this feature is mobile dependent? For example, huawei doc states that the UE should be 3GPP REL6.


. Another possibility is to activate Blind Search where Ue reselects from 2G into 3G UARFCN. This minimizes the information sent to the Ue and therefore accelerates the reselection.

[tabordas]

I'll have a look at your first points later when I have a little more time.
Regarding the feature, yes it only works for R6 and above UE. The rest will do a normal reselection. But for the UE that support the feature the reselection time drops to 2 or 3 seconds...

[ninjafine]

Hi mirc84! Additional things to check.
1. For OP1 and OP2 we can see SI2Quater_Count=1 and SI2Quater_Count=0 and for OP3 SI2Quater_Count=2. This may add up to 2 sec. to wait additional System Information Type 2quater message.
2. Check also System Information Type 3 (SI2quater_POSITION) to chek if OPs are equal in terms of using BCCH ext.
3. Number of FDD_ARFCN in System Information Type 2quater also increases measurements.

[gogotchiya83]

Any update of this issue ?

In our case we have delay in both side, Reselection from 2G->3G & from 3G ->3G

Any help PLZ ?