- This topic has 7 replies, 1 voice, and was last updated 12 years, 3 months ago by winb.
7th September 2007 at 09:09 #49139SantoGuest
I want to know … is there any relationship between RACHBT setting and Handover Success rate ?
Thanks7th September 2007 at 10:08 #49140TomarGuest
RACH busy threshold, defines a threshold for the signal level on the RACH. The general purpose of this parameter is to define a minimum level criterion a received RACH signal must fulfill to be regarded as a real RACH access.
BTS continuously observes the signals received on the RACH slots. As even without any MS RACH access there are always at least some ‘noise’ signals on the RACH slots. The layer 1 subsystem is to evaluate the received signal with respect to specific criteria, e.g. it measures the receive level and checks if it exceeds defined minimum.
The value entered for parameter RACHBT is not only relevant for the CHANNEL REQUEST message on the RACH but also for the HANDOVER ACCESS message on the FACCH! The level evaluation
of RACHBT against the receive level of the handover access burst on the FACCH is exactly the same as for the RACH. Thus, the setting of RACHBT also has an influence on the handover success rate.
From my experiences, value of RACHBT has big impact to the SDCCH Drop rate.
Tomar11th September 2007 at 09:33 #49141SeraGuest
is there relationship between Rx lev Access Minimum and RACHBT setting in Call setup process ? Do we need to use both parameters on call setup process ? i’m little bit confuse about this matter..
Sera11th September 2007 at 14:18 #49142asoGuest
the RX lev Acce min is the parameter which affect after you initiate call ( affect path loss C1)and it value is different than RACHBT
which it is very high than first one.12th September 2007 at 05:50 #49143seraGuest
Why is the value of RACHBT higher than RXLevel Access Minimum? Does it affect the success of Call Setup process? What about the value of RXLevel AMI higher than RACHBT? Can it happen in real network?12th September 2007 at 09:51 #49144TomarGuest
Try to read my article once more. The RXLEV Access Minimum is SysInfo broadcasted on BCCH. And mobile make decision, of received signal is for particular cell is above/below this threshold. The cell level is suitable or not for access. If the RXLEV is stronger than this defined threshold RXLEVACCMIN, than mobile could try to make Random Access on RACH channel. In the BTS is defined RACHBT. If the received RACH access (in the BTS) is below this threshold, than this random access is discarded.
In Siemens is one counter, which counts number of discarded attempts. Set RACHBT according to BTS sensitivity. For proper settings of RACHBT, this counter could indicate wrong path balace.
Tomar12th September 2007 at 12:19 #49145seraGuest
thanks for your kind information.. see u..16th June 2010 at 10:12 #49146winbGuest
i need to know the impact of the FACHBT on the handover,if it’s possible to give me the treshold