Idle Mode and Common Channel Behavior
If the UE has selected a MBMS service that is currently ongoing the UE adds an offset to the normal HCS priority for all cells (serving and neighbor cells) belonging to the MBMS Preferred layer. The offset is configurable and set by the cell parameter hcsPrioOffset. The value is signaled to the UE on the MBMS control channel MCCH. Hierarchal Cell Structures is a license controlled feature, and a software key is necessary for activation. For more information see Handling of License Control. 3.2.4.2
Measurement rules for cell reselection when HCS is used The measurement rules for cell reselection when HCS is used is specified in Reference [3], section 5.2.6.1.2. The following parameters controlling the measurement rules are configurable in the network and sent to the UE in system information SIB3: Table 2
Parameters controlling the measurement rules for cell reselection when HCS is used
Parameter name in 25.304
Corresponding operator configurable parameter name
SinterSearch
sInterSearch
SintraSearch
sIntraSearch
SsearchHCS
hcsSib3Config.sSearchHcs
Slimit,SearchRAT
sRatSearch
SHCS,RAT
sHCSRat
For more details regarding value range etc, see Section 5.2 on page 55. 3.2.4.3
Cell reselection criteria when HCS is used The quality level threshold criterion for HCS (H-criteria) is used to determine whether prioritized ranking shall apply. The H-criteria is defined by: H(s) = Qmeas(s) – Qhcs(s) H(n) = Qmeas(n) – Qhcs(n) – TO(n) Qhcs specifies the quality threshold level for applying the prioritized ranking. (s) and (n) denotes the serving and neighbor cell values respectively. The serving cell value is set by the configurable parameter hcsSib3Config.qHcs. Qhcs for Inter-frequency cell relations is set by the configurable parameter hcsSib11Config.qHcs. For intra-frequency and GSM cell relations the default value according to Reference [4] applies, i.e. Qhcs(n) = 0. TO(n) specifies the temporary offset applied to the H-criteria for a duration of PENALTY_TIME(n) after a timer T(n) has been started. See Reference [3], section 5.2.6.1.4 for more details regarding the start and stop of this timer.
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