Communication system, mobile station, and switching control method

摘要

A UE 300 is connectable to a first radio communication system and a second radio communication system which differs from the first radio communication system and uses multiple frequency bands. The UE 300 receives RRC CONNECTION REJECT which gives an instruction to switch from the first radio communication system to the second radio communication system and an indication on multiple switching target frequencies included in the frequency bands used by the second radio communication system, and, if the multiple switching target frequencies include an unavailable frequency at which the UE 300 is incapable of transmission/reception, searches for only a cell of a switching target frequency among the multiple switching target frequencies exclusive of the unavailable frequency.

主权项

1. A communication system including:
a mobile station connectable to a first radio communication system and a second radio communication system which uses a different radio access technology from the first radio communication system and uses a plurality of frequency bands; and a communication control device configured to control switching of the mobile station from the first radio communication system to the second radio communication system, wherein the communication control device comprises a switching instruction transmission unit configured to transmit to the mobile station a switching instruction which gives an instruction to switch from the first radio communication system to the second radio communication system and an indication on a plurality of switching target frequencies included in the plurality of frequency bands used by the second radio communication system, wherein the switching instruction transmission unit transmits the switching instruction in response to a connection request from the mobile station before acquisition of information relating to a frequency band which is capable of transmission/reception by the mobile station, and the mobile station comprises:
a frequency band determination unit configured to determine frequency bands of the second radio communication system, which is redirection target, indicated in the switching instruction;a frequency selection unit configured to pick out only frequencies of the frequency band in which the mobile station is capable of transmission/reception, out of the frequency band thus determined; anda quality determination unit configured to search only for cells using the frequency included in the frequency band picked out by the frequency determination unit, to determine a reception quality of a radio signal from the cells, and to determine cells satisfying a prescribed reception quality threshold, anda connection target cell processing unit configured to determine a cell for connection with the mobile station among the cells satisfying the prescribed reception quality threshold.