Radio communication system and radio communication method

A radio communication system including a first communication network, a second communication network and a mobile station connectable to an external network via any one of the first communication network and the second communication network, the system comprising:

• a handover function unit configured to control a handover from the first communication network to the second communication network, wherein
• the number of first bearers allowed to be set up with the mobile station and the first communication network is larger than the number of second bearers allowed to be set up with the mobile station and the second communication network,
• the handover function unit controls the handover in accordance with the number of the first bearers already set up with the mobile station and the first communication network and the number of the second bearers to be newly set up with the mobile station and the second communication network, and
• when a second gateway cannot set up all of the second bearers to correspond to the first bearers already set up, the second gateway updates packet filters set up for the first bearers to map the packet filters into packet filters corresponding to the number of the second bearers.