Method and system for mobile communications

Abstract

When a network pages the temporary user mobile identifier of a mobile station, the mobile station sends a response to the network. Next, the network checks the authenticity of the user using a ciphering key, corresponding to the temporary user mobile identifier and a random number. If the temporary user mobile identifier is authenticated, a normal incoming call acceptance procedure is executed. If the mobile station is authenticated although the temporary user mobile identifier is wrong, the network reassigns a new temporary user mobile identifier to the mobile station and stops the current communication. In communication, the network and the mobile station mutually notify encipherment-onset time and negotiate about encipherment manner with each other. In addition, diversity handover is commenced upon a call attempt. Furthermore, if a branch replacement is necessary, the current branch is replaced by new branches capable of executing the diversity handover. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, the mobile station uses the same branch structure and the same communication frequency band for all of calls. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, a branch structure and a communication frequency band, which can continue all of the calls, are selected and used. Therefore, the mobile communications system is suitable for transmission of various sorts of data in accordance with the development of multimedia.

1 . A method for controlling a branch replacement characterized in that at least a current branch between a network and a mobile station are replaced with a plurality of branches necessary for communication using diversity handover when the branch replacement is necessary for the mobile station and when it is recognized that the mobile station can commence communicating using diversity handover if the branch replacement is carried out, thereby enabling the mobile station to commence diversity handover. 
   
   
       2 . A method according to  claim 1 , wherein the network additionally establishes an auxiliary branch for the mobile station, and then releases the current branch, so as to complete the branch replacement for communicating using diversity handover. 
   
   
       3 . A mobile station characterized in that it replaces at least a current branch between a network and the mobile station with a plurality of branches necessary for communication using diversity handover when a branch replacement is necessary for the mobile station and when the mobile station can commence communicating using the diversity handover branches if the branch replacement is carried out, thereby commencing diversity handover. 
   
   
       4 . A base station controller characterized in that it replaces at least a current branch between a network and a mobile station with a plurality of branches necessary for communication using diversity handover when a branch replacement is necessary for the mobile station and when it is recognized that the mobile station can commence communicating using diversity handover if the branch replacement is carried out, thereby enabling the mobile station to commence diversity handover. 
   
   
       5 . A base station controller characterized in that it transmits a message to abase station and a mobile station when a branch replacement is necessary for the mobile station and when it is recognized that, if the branch replacement is carried out, the mobile station can commence communicating by means of intra-cell diversity handover wherein the mobile station and the base station communicate with each other using a plurality of branches, the message including an instruction to carry out the branch replacement and an instruction to add at least one auxiliary branch for additional use in order to communicate using diversity handover. 
   
   
       6 . A base station controller characterized in that it transmits an instruction to a plurality of base stations and a message to a mobile station when a branch replacement is necessary for the mobile station and when it is recognized that the mobile station can commence communicating by means of inter-cell diversity handover if the branch replacement is carried out, the instruction instructing the base stations to set branches necessary for the diversity handover, the message including an instruction to carry out the branch replacement and an instruction to add at least one auxiliary branch for additional use in order to communicate using diversity handover. 
   
   
       7 . A base station characterized in that it replaces a branch for a mobile station and adds at least one auxiliary branch for the mobile station according to instructions of a message once the base station receives the message from a base station controller, the message including an instruction to carry out branch replacement and an instruction to add at least one auxiliary branch for additional use in order to communicate using diversity handover, thereby commencing the intra-cell diversity handover.