PS IRAT Fail: cause Failed Outgoing 3g to 2g PS Handovers due to UE Reselection Back

[Ghost78]

Hi expert,

For Huawei NW, we have high PS IRAT Fail, cause: Failed Outgoing UMTS-to-GSM PS Handovers due to UE Reselection Back to a UTRAN Cell

Could anyone help about this topic, how to investigate this cause? what are the best values of 2G cell parameters? is there any timer which avoid ping pong 3g to 2g and 2g to 3g back?

3g = Huawei
2G = ALU

Many thx

[polo]

check fast reselection from 2G side (ALU)

[Ghost78]

Hi,

isn't fast reselection in idle mode? when the UE handover to 2G cell from 3G UTRAN, it will be in ready , standby or idle status?
What are different 2G ALU parameter related to this issue for each status?

Many thx

[polo]

Verify below parameters:
EN_2G_TO_3G_CELL_RESELECTION
FDD_RSCPmin
FDD_Qmin_Offset
EN_CPICH_2G_3G_Reselection
EN_FAST_3G_Reselection
Qsearch_C
Qsearch_I
Qsearch_P
Qsearch_P_PTM
FDD_Qoffset
FDD_Qmin
FDD_GPRS_Qoffset

[Ghost78]

Hi polo,

when the UE handover to 2g from 3g cell, what will be it's status : idle, PIM or PTM?
i really wanna know the response to know which ALU parameter to change to handle this issue,

Many thx