- This topic has 27 replies, 1 voice, and was last updated 8 years, 6 months ago by Agha.
7th May 2010 at 07:28 #62549HW_JUNIORGuest
Dear Pix/Other Experts
I’m confusing RXLEV_ACCESS_MIN and RACH Min.Access Level
In Huawei System:
RACH Min.Access Level (default): -115dbm
RXLEV_ACCESS_MIN (default): -102dbm
Is there any relation between these parameters? What is the functions of these parameters?
Thanks in advance8th May 2010 at 09:13 #62550HW_JUNIORGuest
any comments dears???10th May 2010 at 06:00 #62551BijoyGuest
RACH Min.Access Level—If the receive level of the RACH burst is lower than the value of RACH Min.Access Level(dbm), the BTS regards this access as an invalid one and no decoding is performed. If the receive level of the RACH burst is higher than the value of RACH Min.Access Level(dbm), the BTS regards that an access request exists on this timeslot, and determines together with the value of Random Access Error Threshold whether the RACH access is valid.
RXLEV_ACCESS_MIN—-Minimum DL receive level of an MS to access the BSS.
Can be taken as RXLEV_ACCESS_MIN is the Minimum DL receive level of the BTS received by MS & RACH Min.Access Level is the minimum UL receive level of the MS reported to BTS
Bijoy10th May 2010 at 06:16 #62552ManiaGuest
Bijoy is right about the description of the two and the difference in their default levels is because of the difference in the receiver sensitivity of MS and BTS respectively it is also good as the UL levels are usually lower so lower reveiver sensitivity helps keeping the path balanced11th May 2010 at 09:27 #62553HW_JUNIORGuest
Thanks a lot for your helps17th May 2010 at 11:28 #62554DaveGuest
And what could be the differences between RACH Access min and RACH Busy Threshold?18th May 2010 at 03:08 #62555machzarGuest
would you explain what is the relation between these two parameter with some our KPI such as SCR, PSR, HOSR, or others. so we have a clearly point of view. thanks before.19th May 2010 at 04:34 #62556ManiaGuest
RACH Acc Min and RACH Busy Threshold are the same thing. Rxlev Access Min is for the DL level19th May 2010 at 07:04 #62557BijoyGuest
There is a subtle difference between the two.
RACH Busy Threshold determines the RACH busy state.For the BTS3X series and DTRX BTSs, this parameter does not affect MS access but affects the reporting of CCCH_LOAD_IND.For BTS 3X,RACH Busy Threshold should be greater than RACH Min.Access Level.
For the BTS24, this parameter has two functions. One function is indicating the level threshold of the MS random access for the system to determine the RACH busy state.The other function is indicating whether the MS access is allowed.
Bijoy20th May 2010 at 05:29 #62558ManiaGuest
Thanks Bijoy for correcting but there is still confusion for the other functions in my mind.
For CCCH_Load_UL the formula would be (No of RACH Frames UL)/ (defined CCCH in UL). how does Rach_BT effect it, other than rejecting a few RACH based on UL Level.
Also the two functions of BTS24 also seem similar i.e determine the level threshold for UL to accept RACH as valid RACH.
Also which vendor is this distribution for.20th May 2010 at 08:59 #62559BijoyGuest
Mania,You are right in both the conclusions,that is the reason I said”Subtle”.
These are parameters of Huawei.
Nokia Also has similar parameters of RG BR 9.x for BTS plus Sites
Bijoy5th May 2012 at 11:03 #62560AghaGuest
it is still confusing the difference of RACH min. Access and RACH Busy Thr.please elaborate more and why in BTS 3X, Threshold is greater than the UL Access level?13th May 2012 at 14:03 #62561AghaGuest
please explain below post.13th May 2012 at 18:48 #62562BijoyGuest
Rach Busy Thresold:
For the BTS3X series and double-transceiver BTSs, this parameter specifies the level threshold for the MS random access when the BTS determines the RACH busy state. When the receive level of the random access burst timeslot is greater than this threshold, the BTS considers that the timeslot is busy. For the BTS3X series and the double-transceiver BTSs, this parameter only indicates whether the timeslot is busy. The threshold setting does not affect the normal access of the MS.
For the BTS2X series (excluding the BTS24), this parameter specifies the level threshold for the BTS to determine an MS random access.When the receive level of the random access burst timeslot is greater than this threshold and the access demodulation is successful, the BTS considers that the timeslot is busy and determines whether the RACH access is valid based on the parameter Random Access Error Threshold. For the BTS2X, the parameter RACH Busy Threshold is used to determine whether the timeslot is busy. In addition, the parameter affects the normal access of the MS. The MS access is allowed only when the level of the MS random access burst is greater than the RACH Busy Threshold.
For the BTS24, this parameter has two functions. One function is indicating the level threshold of the MS random access for the system to determine the RACH busy state. When the receive level of the random access burst timeslot is greater than this threshold, the BTS considers that the timeslot is busy. The other function is indicating whether the MS access is allowed.The MS access is allowed only when access level (including random access and handover access) is greater than the threshold.
RACH Min.Access Level:
For the BTS3X, this parameter specifies the level threshold for the random access of the MS. If the receive level of the RACH burst is smaller than the value of RACH Min.Access Level, the BTS regards this access as an invalid one and no decoding is performed. If the receive level of the RACH burst is greater than the value of RACH Min. Access Level, the BTS considers that an access request exists on this timeslot, and determines together with the value of Random Access Error Threshold whether the RACH access is valid.
Generally, RACH Busy Threshold is higher than RACH Min.Access Level. Therefore, for the BTS24, RACH Min.Access Level is shielded. For the BTS2X (excluding the BTS24), the RACH Min.Access Level parameter is invalid.
So ,RBT is the only available parameter in BTX2X series which serves the purpose of RALM too,while in BTS3X,we have both RBT and RALM.14th May 2012 at 12:35 #62563AghaGuest
Thanks alot Sir Bijoy. Now its clear wrt BTS versions.please one more issue, which i hv to discussed, In remote area HSR of 02 cells of different sites (In/Out HSR of Neigbr)degraded. from the same time DCR increased and due to N200 increased.No Hardware/Intf issue.and HO to other sites from these cells are alright.it might be due to BTS out of syn..plz tell me what steps should be taken to reduce and why it happened suddenly?