RACH Min.Access Level & RXLEV_ACCESS_MIN

any comments dears???

Hi,
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 balanced

And what could be the differences between RACH Access min and RACH Busy Threshold?

Hi Dave,
RACH Acc Min and RACH Busy Threshold are the same thing. Rxlev Access Min is for the DL level

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.

HI Bijoy,
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?

Hi Agha

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.