Repeated FACH/SACH

Is there somebody to know ??

Hi Pix,
we tried to active this feature for some cells but I dont see any performance changes after activation…
What are better values for thresholds REP_DL_FACCH_THRES_AMR_FR/HR? In our configuration we use the highest thresholds, this is good or not?
Is it possible to give me your e-mail to send you our settings to say whether are ok or not?

hi vanG,

I totally forgot…

For the repeated FACCH – impact is on the Outgoing HO Efficiency Rate, and possible on the RTCH Drop Rate.

Here are my recommendations, for RFACCH, to see if there is an impact or not:

EN_REP_DL_FACCH = 2: enabled for LAPDm command frames + LAPDm response frames

REP_DL_FACCH_LEGACY_SUPPORT = 1: repeated DL FACCH enabled for all AMR mobile stations

REP_DL_FACCH_THRES_AMR_FR = 8: 12,2 kbit/s

REP_DL_FACCH_THRES_AMR_HR = 5: 7,40 kbit/s

————————–
and for the RSACCH:

EN_REP_SACCH = 1: enabled

RADIOLINK_REP_DL_SACCH = 14

L_RXQUAL_DL_P_AMR_RXACCH = 3.5
L_RXQUAL_UL_P_AMR_RXACCH = 3.5

REP_DL_SACCH_THRES = 3
REP_UL_SACCH_THRES = 3
REP_DL_SACCH_WS = 10
REP_UL_SACCH_WS = 10

—————————

now, keep in mind that RxACCH will be visibly useful only if codec is changed to lower codecs (in FR, around 7kb/s, in HR around 4kb/s)
If you stay at 12.2kb/s, then the rep. xACCH will show no improvement at all !!

regards
pix

Hi Pix,
I changed our SACH/FACH parameters as your recommendation, but I think that the RADIOLINK_REP_DL_SACCH = 14 is not so good because after changes the call drop due to cause “too low level in DL” increased almost triple…
And I can’t find and chack in RNPO the REP_DL/UL_SACCH_THRES and REP_DL/UL_SACCH_WS parameters.

p.s.What do you think for the timers that I mentioned in previous post?

>>rrb_bg

Hi Pix,
about this timers, what do you think how I can decrease the call drop due to cause “Other causes”. As I checked in documentation this “other causes” are due to Handovers and these timers are related to them…Is it possible to improve these type of drops and how?
About RADIOLINK_REP_DL_SACCH I’ll say tommorow, because I changed back to previous value= 30 and waiting for more statistics..
Thank you for your co-operations !!
Best regards,
p.s. What is your e-mail?

Hi Pix, thank you for your answer..
If RADIOLINK_REP_DL_SACCH is not related to my drop increase, what can be the problem changes?
I just changed RADIOLINK_REP_DL_SACCH=30,
REP_DL_FACCH_LEGACY_SUPPORT = 1;

This my current parameter for cell that we tried repeated SACCH/FACCH :
RADIOLINK_RECOVERY_THRES=33;
RADIOLINK_FAILURE_THRES=36;
RADIOLINK_FAILURE_THRES_AMR=36;
RADIOLINK_TIMEOUT=32;
RADIOLINK_REP_DL_SACCH=30(at the moment);
EN_REP_DL_FACCH = 2;
EN_REP_SACCH=1(ENABLE);
REP_DL_FACCH_LEGACY_SUPPORT = 1;
L_RXQUAL_DL_P_AMR_RXACCH=4.0;
L_RXQUAL_UL_P_AMR_RXACCH=4.0;
REP_DL_FACCH_THRES_AMR_FR=12.2;
REP_DL_FACCH_THRES_AMR_HR=7.4;

>>rrb_bg

I changed to the previous values ​​L_RXQUAL_DL (UL) _P_AMR_RXACCH = 2.0 and REP_DL_FACCH_LEGACY_SUPPORT = 1 and now “Call Drop_DL level” decreased to values ​​before the changes …
What do think about my other question? How can I improve the “Call Drop_Other cause”?
Thanks for your help …
Regards,