20.4 Temporary UE capability restriction and removal of restriction

For MUSIM operation, a MUSIM device in RRC_CONNECTED state in Network A may indicate its preference on temporary UE capability restriction or removal of restriction via UE assistance information with Network A when the MUSIM device needs transmission or reception in Network B (e.g., including start/stop connection to Network B). Network A is NR and Network B can either be E-UTRA or NR. The MUSIM device may request a temporary capability restriction only after the Network signals via RRC that this is allowed.

When configured to do so, a MUSIM device can indicate one or more of the following temporary capability restriction or removal of restriction to the Network A:

• A MUSIM device can explicitly request SCell(s) or SCG to be released;
• A MUSIM device can indicate its preference on temporary maximum MIMO layers and/or supported channel bandwidth for specific serving cells for both UL/DL;
• A MUSIM device can indicate its preference on the temporary maximum number of CCs per UL/DL;
• A MUSIM device can indicate its preference on the concerned band(s) or band combination(s) (e.g. avoided and/or affected band(s) or band combination(s)) based on a band-filter list configured by network. For affected band(s) and band combination(s), this preference can include temporary maximum MIMO layers and/or supported channel bandwidth for both UL/DL;
• A MUSIM device can indicate the measurement gap requirement changes.

When it is allowed by Network A in SIB1, a MUSIM device can indicate in RRCSetupComplete/RRCResumeComplete/RRCReestablishmentComplete message to the Network A that its capabilities are temporarily restricted due to ongoing transmission/reception in Network B. This indication allows Network A to know whether UE capabilities without restrictions can be used by Network A, or if Network A needs to configure the UE to indicate its temporary capability restrictions, as described above. When configured to do so, a MUSIM device can also indicate to the Network A there is no temporary capability restriction via UE assistance information.

When a MUSIM device is in RRC_CONNECTED state in both Network A and Network B, if Network B is NR, it is up to UE implementation to select which network to request temporary UE capability restriction; if Network B is E-UTRA, the request for temporary UE capability restriction can only be performed on Network A.