Qqualmin = 0 leads to CELL FACH and CELL PCH UE =0

[fahmi]

Dear Huawei experts,

Why setting Qqualmin=0 (to prevent idle UE to select F3) CELL_FACH and CELL_PCH UEs number reduce to 0.

HSDPA UE number reduce slightly but still OK.

Drop PS increase !!

how to explain this

[faisaladeem]

Setting Qqualmin=0 will make cell not qualified for access and the UE will try to reselect another cell meeting minimum access criteria. If the UE is doing state transition from DCH->FACH, drops on FACH might increase during this reselection in FACH state.

[fahmi]

This is it. Why there is a FACH drop during reselection in FACH state ?

[faisaladeem]

There is no fast power control and soft handover gain in FACH state so the chances of drops are higher on common control channels. Secondly there are some Qualcomm chipsets (used in iphone 4 and other UEs) that are reported to have higher drops in FACH state in a DC carrier combination (for example if F2/F3 are DC cells, there T_cell should be aligned and that confuses the UE and it takes inter-frequency measurements as intra-frequency leading to higher drops on F3; you may ask //H for more details and case study on this). Lastly from DCH to FACH state transition, UE has to first re-select another cell (which is meeting qqualmin/qrxlevmin criteria) and then send the physical channel reconfiguration response. If this reselection takes longer, the response times out and can result in a drop! (also discussed in a similar thread here http://www.finetopix.com/showthread....ht=#post237074)

[fahmi]

This is the problem, I cannot differentiate between idle parameters and CELL_FACH/PCH parameters !
Even after SIB4 activation, no difference noticed.