quality of the GSM cell falls below a certain threshold Measurement reports The requirements on the measurement reporting are: the UE will include both UTRAN and GSM measurements in the periodic meas- urement reports which are sent to the BSS The UMTS Network and Radio Access Technology the operator will have the capability to control the minimum number of GSM cells in the serving band, the minimum number of cells in UMTS, and the minimum number of cells in other GSM bands which are included in the measurement report if there is any space remaining in the measurement report after inserting the mini- mum number of entries for each reporting type, the MS will use this space to insert further measurements in decreasing order of priority both the existing format measurement report, and the extended format measurement report (e.g. 76/00 and 2B00-009) will be supported by the MS Release 99 and newer MSs will support extended measurement reporting the network will inform the MS whether extended measurement reporting is sup- ported; the default measurement reporting type is the normal measurement report- 7. Signalling The signalling between the GSM network and UMTS network to perform handover needs the following modifications: the GSM system will provide the UMTS system with the target ID of the RNC to which the call is being directed Table 4.32 Allowed Handover for GSM Release 99 [19] GSM CS GSM GPRS GSM ECSD GSM EGPRS nRT GSM GPRS COMPACT , handover permitted; X , handover not permitted. 4.3.16 Other FDD Mode Physical Layer Procedures Paging Channel (PCH). The MS gets a Paging Indicator (PI) belonging to a paging group once it registers in a network. The PI appears periodically on the Paging Indicator Channel (PICH) whenever paging messages exists, and the MS decodes9 the next PCH frame transmitted on the secondary CCPCH, seeking for the messages corresponding to 9 Battery life duration will increase with he lowest amount of PI detection events. The UTRA Physical Layer Design The RACH. To cope with the power control un