Abstract: A method of handling NAS signaling connection release and rejection of paging under transmission failure for MUSIM UE is proposed. UE has established a NAS signaling connection or has received a paging from the network on the first USIM. However, UE has more important job to be started or ongoing on the second USIM. UE then initiates a service request procedure by transmitting a service request to the network, to release the NAS signaling connection or to reject the paging on the first USIM. Due to poor radio signal quality, a transmission failure occurred. In one novel aspect, UE does not restart the service request procedure. Instead, UE locally releases the NAS signaling connection on the first USIM. As a result, UE is able to start the more important job on the second USIM, or the user experience on the second USIM is improved.

Abstract: A method of handling NAS signaling connection release under mobility management congestion control for MUSIM UE is proposed. A MUSIM UE has established a NAS signaling connection on a first USIM in connected mode. Later on, the MUSIM UE has more important job to be started on the second USIM. The MUSIM UE wishes to initiate a service request procedure by transmitting a service request to the network, to release the NAS signaling connection on the first USIM. However, under the 5GMM/EMM signaling congestion condition with timer T3346 running, the AMF/MME rejects 5GMM/EMM signaling requests from UE. In one novel aspect, the MUSIM UE requests the network to release the NAS signaling connection while timer T3346 is still running. As a result, the MUSIM UE is able to start the more important job on the second USIM, or to improve user experience on the second USIM.

Abstract: A method of handling (alternative) IMSI value for MUSIM UEs supporting paging timing collision control in an EPS network is proposed. For a MUSIM UE and EPS supporting paging timing collision control, the MUSIM UE and the network can request and negotiate an IMSI offset for the IMSI value on one of the USIM card through a TAU or ATTACH procedure. When lower layer failure occurs, the network may not successfully receive a TRACKING AREA UPDATE COMPLETE (or ATTACH COMPLETE) message from the UE, and therefore the network may not know which IMSI value UE will use. Accordingly, the network needs to use both possible (alternative) IMSI values when deriving paging timing for the UE until one of the (alternative) IMSI values is considered invalid.

Abstract: A method of maintaining a proper forbidden tracking area identifier (TAI) list is proposed. A UE receives a service area list comprising one or more allowed tracking areas. The service area list may be carried by a configuration update command. UE compares if any of the allowed tracking area having a matching TAI in the forbidden TAI list. Accordingly, UE removes any allowed tracking areas having a matching TAI from the forbidden TAI list. In one embodiment, UE sends a REGISTRATION REQUEST message to initiate a registration procedure. In response, UE receives a REGISTRATION ACCEPT message, which may also carry a service area list. UE may remove the allowed tracking area having a matching TAI from the forbidden TAI list. However, if UE is registered for emergency services, then UE shall not remove the allowed tracking area from the forbidden TAI list.

Abstract: A method of maintaining a proper forbidden tracking area identifier (TAI) list is proposed. A UE receives a service area list comprising one or more allowed tracking areas. The service area list may be carried by a configuration update command. UE compares if any of the allowed tracking area having a matching TAI in the forbidden TAI list. Accordingly, UE removes any allowed tracking areas having a matching TAI from the forbidden TAI list. In one embodiment, UE sends a REGISTERATION REQUEST message to initiate a registration procedure. In response, UE receives a REGISTRATION ACCEPT message, which may also carry a service area list. UE may remove the allowed tracking area having a matching TAI from the forbidden TAI list. However, if UE is registered for emergency services, then UE shall not remove the allowed tracking area from the forbidden TAI list.

Abstract: A mobile communication device is provided. The mobile communication device comprises a radio frequency (RF) module, a first communication module, a second communication module and a control module. The RF module is used to transmit and receive RF signals. The first communication module utilizes the RF module to establish a first communication connection. The second communication module utilizes the RF module to establish a second communication connection. The control module arbitrates requests to access the RF module from the first communication module and the second communication module.