A mobile communication device, comprising: a wireless transceiver, configured to perform wireless transmission and reception to and from a first network supporting only Packet-Switched services or a second network supporting Circuit-Switched services; and a controller, configured to: receive a request or paging for a Circuit Switch Fallback related, CSFB-related, call originated from or terminated to the mobile communication device, after transmitting a request message of a Tracking Area Updating, TAU, procedure to the first network, receive a rejection message of the TAU procedure from the first network via the wireless transceiver when the CSFB-related call is pending, determine whether the rejection message comprises a predetermined rejection cause with a cause value of 9, 10, or 40 specified in 3rd Generation Partnership Project, 3GPP, technical specification 24.301 V13.1.0 published 20.03.2015 for a Long Term Evolution, LTE, based technology, and in response to the rejection message comprising the predetermined rejection cause, select the second network to make the CSFB-related call via the wireless transceiver without re-attaching to the first network. a wireless transceiver, configured to perform wireless transmission and reception to and from a first network supporting only Packet-Switched services or a second network supporting Circuit-Switched services; and a controller, configured to: receive a request or paging for a Circuit Switch Fallback related, CSFB-related, call originated from or terminated to the mobile communication device, after transmitting a request message of a Tracking Area Updating, TAU, procedure to the first network, receive a rejection message of the TAU procedure from the first network via the wireless transceiver when the CSFB-related call is pending, determine whether the rejection message comprises a predetermined rejection cause with a cause value of 9, 10, or 40 specified in 3rd Generation Partnership Project, 3GPP, technical specification 24.301 V13.1.0 published 20.03.2015 for a Long Term Evolution, LTE, based technology, and in response to the rejection message comprising the predetermined rejection cause, select the second network to make the CSFB-related call via the wireless transceiver without re-attaching to the first network. receive a request or paging for a Circuit Switch Fallback related, CSFB-related, call originated from or terminated to the mobile communication device, after transmitting a request message of a Tracking Area Updating, TAU, procedure to the first network, receive a rejection message of the TAU procedure from the first network via the wireless transceiver when the CSFB-related call is pending, determine whether the rejection message comprises a predetermined rejection cause with a cause value of 9, 10, or 40 specified in 3rd Generation Partnership Project, 3GPP, technical specification 24.301 V13.1.0 published 20.03.2015 for a Long Term Evolution, LTE, based technology, and in response to the rejection message comprising the predetermined rejection cause, select the second network to make the CSFB-related call via the wireless transceiver without re-attaching to the first network.