HS to DCH (DCH to HS) Channel switch

[BENRHOUMASALEM]

Dears,
Can someone explan when there is HS to DCH (DCH to HS) Channel switch ?
Please to share docs ?
BR,

[palo]

In order to provide more data in 3GPP rel 5 it was implemented the idea of the hsdpa (with the hs-dsch channel) .But eventhough it satisfies the need of the operators for higher data throughp still it had a major issue when the UE was “communicating” with multipleNodeBs (SHO) as the delay inserted with the HS-dsch channel was about 300-500 msec . In order to avoid this delay for services which are sensitive to it (example:VoIP) it was proposed to 3GPP the usage of the DCH in order to reduce the delay during to handover from 300-500 msec to less than 20 milisec .
Hope it was useful to you !

[BENRHOUMASALEM]

Many thanks Palo,
For example, when the UE is on DCH stat with HSDPA connexion and an ISHO comming, a channel will switch to DCH and after that the ISHO procedure will continu.
I ask for the total senario of channel switch from HSDPA to DCH and the inverse switch.
BR,

[senjamir]

Hi,

If you are using E******* equipment you can control this switches by checking on the parameter hsToDchTrigger. This can have multi values.

1. poorQualityDetected: Applies to the case when triggered by bad connection quality
2. changeOfbestCellIntraRnc: Applies to the case when triggered by change of best cell, when the new best cell is an intra-RNC cell.
3. servHsChangeIntraRnc: Applies to the case when the serving cell is removed from the active set and the best cell is an intra-RNC cell.
4. servHsChangeInterRnc:Applies to the case when the serving cell is removed from the active set and the best cell is an inter-RNC external cell
5. changeOfBestCellInterRnc:Applies to the case when triggered by change of best cell, when the new best cell is an inter-RNC external cell.

From experience i normally use poorQualityDetected.

By the way you are right about the idea on the channel switching.

I hope this helps.

Best regards,
Sen Jamir

[BENRHOUMASALEM]

Many thanks Sen,
What about NSN ?
BR,

[senjamir]

Many thanks Sen,
What about NSN ?
BR,

Hi Check if this can be helpful.

No pass.

Best regards,
Sen Jamir

[marcengo]

Other scenarios where HS to DCH will happen:
Whenever the UE needs to enter Compressed Mode, if HSDPA CM is not activated. This works for IFHO and ISHO. Check WBTS:BTSSupportForHSPACM
Whenever the UE needs to perform a handover between RNCs with IuR, if HSPA over IuR is not activated. This works for Intra-Freq HO. Check IUR:HSPAOverIur and RNFC:HSPAOverIurExt.

Enjoy!