Dual mode communication system, dual mode communication method and dual mode communication user equipment

A dual mode communication method, in which communication user equipment being able to connect selectively to a plurality of communication systems, switches the communication systems to which the user equipment should be connected, comprising steps of:

• comparing a remaining battery level of the user equipment, communicating over a first communication system, with a predetermined threshold;
• determining whether or not the user equipment can communicate using a second communication system, which can operated with lower power consumption than the first communication system when the remaining battery level falls below the threshold;
• and
• switching from a connection between the user equipment and the first communication system to a connection between the user equipment and the second communication system, if the user equipment can establish communicating over the second communication system.

Dual mode communication user equipment, which can be connected to either of a first communication system or a second communication system, comprising:

• a battery;
• detection means for detecting a remaining level of the battery;
• and
• switching means for performing handover from the first communication system to the second communication system, when the remaining battery level falls below a threshold during communication over the first communication system.

A dual mode communication system, in which dual mode communication user equipment switches communication systems to be connected, comprising:

• detecting unit for detecting that a remaining battery level fell below a first threshold in user equipment communicating over a first communication system;
• determining unit for determining whether or not the user equipment is able to communicate using a second communication system, which can be operated with lower power consumption than the first communication system;
• and
• switching unit for switching a connection between the user equipment and the first communication system to a connection between the user equipment and the second communication system, when it is determined that communication can be established using the second communication system.