- This topic has 10 replies, 1 voice, and was last updated 9 years, 8 months ago by paraHO.
5th March 2008 at 10:49 #51339BilalGuest
Random Access Success Rate has the formula : 100 * No. of successful random accesses / No. of random access attempts. Can anybody tell me what is a successful random access? I mean when this counter is pegged?6th March 2008 at 11:45 #51340PixGuest
you need to find an ericsson guy… i’m the alcatel guy 🙂6th March 2008 at 11:59 #51341BilalGuest
You can give the Alcatel’s definition for it, I don’t think there will be much difference 🙂6th March 2008 at 14:12 #51342PixGuest
That’s the thing, we don’t have those in alcatel.
Let’s try to guess.. the MS starts with a channel request on RACH, the “Channel Required” reaches the BSC, and then is counted as a “random access attempt”.
The BSC sends a Channel Activation to the BTS, if the SDCCH is not congested. Counted as a “SDCCH Request”.
The BTS replies with a Channel Activation Ack (not counted)
Then the BSC sends a Immediate Assign Command, counted as a “SDCCH allocated”.
Maybe in your formula, this is the ratio CHANNEL ACTIVATION / CHANNEL REQUIRED ?
I really cannot be sure… this indicator is not provided by alcatel. it can be computed manually though.6th March 2008 at 14:30 #51343BilalGuest
Got the answer. But it creates another confusion.
Successful Random Accesses are all except failed random accesses.The failed random access counter is incremented for a Random access received with too high TA, values that are not used or in case of “software file congestion”.
That means every RACH attempt with less than max TA and defined cause value is a successful Random Access. But Ericsson says poor BSIC planning can be a cause of bad Random Access Success Rate, how is this? Even a phantom RACH intended for another cell must have a valid cause value and hence it must be treated as a Successful Random Access.Any idea?6th March 2008 at 16:06 #51344pixGuest
you’re right, a RACH on a BCCH is not “failed” even though there is a poor BSIC-BCCH plan.
in my opinion, the only problem could be a RACH sent on a BCCH frequency that is used as well few kilometers away. In this situation, the second cell might receive this RACH with a distance > “rach timing advance”.14th August 2011 at 23:58 #51345Ramlakhan AnvitGuest
What is the meaning of Um interface, thus what does it stands for. I know it interfaces the MS and BTS. But what is the meaning of U and m in Um interface.
Thanx.15th August 2011 at 08:03 #51346pixGuest
Hello and welcome to internet.
Wikipedia / Um interface
“It is called Um because it is the mobile analog to the U interface of ISDN.”
pix16th August 2011 at 12:30 #51347paraHOGuest
‘Um’ is an acronym for “User Mobile”16th August 2011 at 17:04 #51348pixGuest
glad to see you are still around !
pix16th August 2011 at 20:20 #51349paraHOGuest
Hi Pix – thanks. Just can’t keep away from the forum 😉