1.1.1.
Measurements
For a 3G cell that has h as GSM neighbors defined, defined , the decision about when the GSM measurements are performed is based on the parameter sRatSearch in relation relation to Squal. The parameter parameter Squal is defined as QqualMeas – qQualMin qQualMin.. If the Squal value is larger than the parameter sRatSearch sRatSearch,, the UE does not perform measurements on GSM cells. If the Squal value is less than or equal to the parameter sRatSearch,, the UE performs measurements on the GSM neighbors. If sRatSearch the value of sRatSearch of sRatSearch is not sent for the serving cell (by setting sRatSearch = 0), 0), the UE always performs measurements on GSM cells. Squal = QqualMeas – qQualMin = CPich_Ec/Nomeas – qQualMin As illustrated in the example below, qQualMin = -18 dB and sRatSearch = 4 dB. As the Ec/Io of the pilot pilot drops below -14 dB, dB, the UE will begin measuring GSM candidates assuming they are provided as neighbors in SIB 11/12. 11/12. If the Ec/Io of the current pilot pilot improves and exceeds -14 dB, the UE will cease measuring measurin g GSM candidates. The parameters qQualMin and sRatSearch are cell-based parameters and are found in the UtranCell object.
In order to trigger GSM measurements based on RSCP measurements relative to qRxLevMin qRxLevMin,, the sHcsRat parameter is used. The behavior behavior of these measurements is similar similar to the Ec/Io case. Assuming qRxLevMin = -111 dBm and sHcsRat = 3 dB, the UE will begin measuring GSM candidates when the current pilot’s RSCP drops below
-108 dBm. If the RSCP of the current pilot improves and exceeds -108 dBm, the UE will cease measuring GSM candidates. The default value for this parameter is -105 dB, which deactivates the parameter and only allows the UE to trigger GSM measurements based on Ec/Io. Because Ec/Io measurements are not a complete indication of quality, especially at the UMTS network edge, it is recommended that sHcsRat parameter be enabled. The parameter fachMeasOccaCycLenCoeff is used to control the inter frequency and IRAT cell reselection measurements of a UE in CELL_FACH state. A UE in CELL_FACH state is allowed to make inter frequency and/or IRAT measurements only when this parameter fachMeasOccaCycLenCoeff > 0. If there are only GSM neighbors or inter-frequency neighbors defined for a cell, then fachMeasOccaCycLenCoeff should be set to 4 so that the UE will leave the FACH channel every 16 th frame to perform measurements on these neighbors. If a cell has both GSM and Inter-frequency neighbors, then this parameter should be set to a value of 3, so that the UE will leave the FACH channel every 8 th frame to perform measurements on the inter-frequency and GSM neighbors. Since T-Mobile networks will have only 1 WCDMA carrier to start with, for cells that have GSM neighbors defined, this parameter is recommended to be set to 4 . For any cell with no IRAT neighbors or Inter frequency neighbors, fachMeasOccaCycLenCoeff should be set to 0.
