UTRANNCELL BlindHoPriority for CSFB

[fekeme]

Hello all,

I was trying to manage the CSFB strategy for an operator for a while. There was not much resources on the details of this parameter on the internet when I needed. So, after running some configurations, I am fully clarified with Blind Handover Priority parameter of UTRANNCELL MO within Huawei network.

Briefly, once the BlindHoPriority defined for any UTRAN neighbor, in case the CSFB policy is Redirection, Redirected carrier is selected based on the frequency of the utran neighbor whose BlindHoPriority parameter is the highest. If several utran neighbors from different utran carriers hold the highest BlindHoPriority, then the carrier to redirect is chosen based on the CS Service Priority parameter of the carriers in UTRANNFREQ.

If you need more detail on this subject I am here to reply.

Regards.

[hassan.attique]

It is not entirely correct. There is reserve switch which works in round robin fashion in order to keep CS Traffic on 3G carrier evenly distributed. Also it case or Redirection if you have enabled Flash CSFB it will report 16 3G neighbor(Based on parameter configuration) its upto Ue to select suitable candidate.


Hello all,

I was trying to manage the CSFB strategy for an operator for a while. There was not much resources on the details of this parameter on the internet when I needed. So, after running some configurations, I am fully clarified with Blind Handover Priority parameter of UTRANNCELL MO within Huawei network.

Briefly, once the BlindHoPriority defined for any UTRAN neighbor, in case the CSFB policy is Redirection, Redirected carrier is selected based on the frequency of the utran neighbor whose BlindHoPriority parameter is the highest. If several utran neighbors from different utran carriers hold the highest BlindHoPriority, then the carrier to redirect is chosen based on the CS Service Priority parameter of the carriers in UTRANNFREQ.

If you need more detail on this subject I am here to reply.

Regards.

[fekeme]

Well, No. The Reserve switch you mentioned (CSFallBackBlindHoCfg.UtranCsfbBlindRedirRrSw (http://127.0.0.1:7890/pages/GEE01221/05/GEE01221/05/resources/EN/LTE_FDD/eNodeB/Para/MML/ratL/para/CSFallBackBlindHoCfg-UtranCsfbBlindRedirRrSw.html)) appears on the stage (if enabled) only when several multiple Utran Carriers share the same connect priorities and have utranncells with equal BlindHoPriorities.

This is from HDX:
When a UE performs an E-UTRAN-to-UTRAN blind handover, neighboring UTRAN cells must be configured. When the UE performs an E-UTRAN-to-UTRAN blind redirection, neighboring UTRAN frequencies and connect frequency priorities other than neighboring UTRAN cells must be configured.
During frequency selection, the eNodeB preferentially frequencies on which neighboring cells operate. Then, the eNodeB selects frequencies based on blind handover priorities.



If no blind handover priority is 0, the eNodeB preferentially selects the frequency corresponding to the cell that has a higher blind handover priority.
If all blind handover priorities are 0, the eNodeB selects the frequency based on connect frequency priorities. It preferentially selects the frequency with the highest connect frequency priority. If multiple frequencies are of the same priority, the eNodeB selects the blind redirection frequency in a round-robin manner. This ensures that the UE accesses each frequency equally. This function is specified by the CSFallBackBlindHoCfg.UtranCsfbBlindRedirRrSw (http://127.0.0.1:7890/pages/GEE01221/05/GEE01221/05/resources/EN/LTE_FDD/eNodeB/Para/MML/ratL/para/CSFallBackBlindHoCfg-UtranCsfbBlindRedirRrSw.html) parameter.




As per my trials on site, I can confirm the same.

For example, our network operate on 5 UTRAN carriers (F1-F2-F3 U2100, F4-F5 U900), CSFB method is Flash Redirection. F1, F2 and F4 configured as UTRANNFREQ with equal connected mode priorities.
- If no UTRANNCELL defined, Fallback carrier is randomly selected among F1-F2-F4 when RrSw is disabled. When RrSw enabled, F1-F2-F4 selected one by one in every other CSFB.
- If some neighbors defined only from F1, always F1 is selected regardless of other priorities. Cells for SI are selected randomly. If any cell has other than 0 priority, its SI is sent for Flash Redirection.
- If some neighbors defined from F1 and F4, the frequency for redirection is selected among F1 and F4, based on the BlindHoPriority of the UTRANNCELLs. If all 0, than RrSw takes affect. When multiple neighbors from F1 and F4 have BlindHoPriority, the carrier to fallback is the carrier of the cell with highest BlindHoPriority. Only when, say two utranncells from multiple carriers have same highest BlindHoPriority (say 32), the fallback carrier is selected by RrSw.