Radio communications system and method for mobile assisted handover between a private network and a public mobile network

A method for mobile assisted handover between a private radio communications network connected to a wire line switch and having a wire line number and a public land mobile network of a first communication connection between the mobile terminal and the wire line switch including a first radio communication connection between the mobile terminal and the private radio communications network, said method comprising the steps of:

• monitoring a base station of the public land mobile network at the mobile terminal and synchronizing the mobile terminal to the base station of the public land mobile network;
• establishing the first radio communication connection between the mobile terminal and a base station of the private radio communications network which is not coordinated with the base station of the public land mobile network, in that common shared frame timing is not provided between the private radio communications network and the public land mobile network, by synchronizing the base station of the private radio communications network to the mobile terminal;
• detecting a signal quality of the first radio communication connection from the private radio communications network at the mobile terminal;
• establishing a second radio communication connection between the mobile terminal and the public land mobile network simultaneously with the first radio communication connection if the detected signal quality has violated a predetermined switching criteria;
• and
• reporting the wire line number of the private radio communications network to the public land mobile network over the second radio communication connection.

A radio communications mobile terminal for use with a private radio communications network connected to a wire line switch and having a wire line number located within a public land mobile network, comprising:

• means for monitoring a base station of the public land mobile network at the mobile terminal and synchronizing the mobile terminal to the base station of the public land mobile network;
• means for establishing a first radio communication connection between the mobile terminal and a base station of the private radio communications network which is not coordinated with the base station of the public land mobile network, in that common shared frame timing is not provided between the private radio communications network and the public land mobile network by synchronizing the base station of the private radio communications network to the mobile terminal;
• detecting means for detecting a signal quality from said private radio communications network during the first radio communication connection between said mobile terminal and said private radio communications network;
• simultaneous communication establishing means responsive to said detecting means for establishing a second radio communication connection between said mobile terminal and said public land mobile network simultaneously with said first radio communication connection if said detected signal quality has violated a stored switching criteria;
• and,
• wire line reporting means for reporting said stored wire line number to said public land mobile network over said second radio communication connection.

A radio communications mobile terminal for use with a TDMA private radio communications network connected to a wire line switch and having a wire line number located within a TDMA public land mobile network, comprising:

• radio transceiving means for receiving and transmitting radio communications signals between said mobile terminal and said private radio communications network and between said mobile terminal and said public land mobile network, wherein the private radio communications network is not coordinated with the public land mobile network in that common shared frame timing is not provided between the private radio communications network and the public land mobile network;
• detecting means operably connected to said radio transceiving means for detecting a signal quality from said private radio communications network during a first radio communication connection between said mobile terminal and said private radio communications network;
• comparing means operably connected to said detecting means for comparing said detected signal quality to a predetermined switching criteria;
• simultaneous communication establishing means and electrically connected to said transceiving means and responsive to said comparing means for establishing a second radio communication connection between said mobile terminal and said public land mobile network simultaneously with said first radio communication connection if said detected signal quality has violated said predetermined switching criteria, said simultaneous communication establishing means including synchronizing means operably connected to said radio transceiving means for synchronizing radio communications between said mobile terminal and said private radio communications network and said public land mobile network so as to provide a common frame timing for all simultaneous radio communications;
• and,
• reporting means for reporting said wire line number to said public land mobile network and requesting rerouting of said first radio communication connection from said private radio communications network to said public land mobile network over said second radio communication connection.