Device and method for performing handoff in mobile communication system

A terminal apparatus in a mobile communication system, comprising:

• a receiver for receiving data for a period of consecutive first and second frames, each of said frames being divided into a first interval and a second interval following the first interval;
• a handoff determiner for determining a handoff target base station by analyzing a strength of the received signal;
• and
• a controller for applying to the receiver a signal transmitted from a base station presently in communication with the terminal in the first interval of the first frame and in the second interval of the second frame, and for applying to the handoff determiner signals transmitted from other base stations in the second interval of the first frame and the first interval of the second frame, in a handoff mode.

A handoff device of a mobile communication system, comprising:

• a base station apparatus comprising:
• a transmitter for generating transmission data for a period of consecutive first and second frames;
• a controller for dividing each of said first and second frames into a first interval and a second interval following the first interval, and for controlling said transmitter to transmit respective frame data in the first interval of the first frame and the second interval of the second frame and to stop transmission of the data in the second interval of the first frame and the first interval of the second frame;
• and
• a terminal apparatus comprising:
• a receiver for receiving data for the period of consecutive first and second frames;
• a handoff determiner for determining a handoff target base station by analyzing a strength of the received signal;
• and
• a controller for applying a signal transmitted from a base station currently in communication with the terminal in the first interval of the first frame and the second interval of the second frame, and applying to the handoff determiner signals transmitted from other base stations in the second interval of the first frame and the first interval of the second frame, in a handoff mode.

A transmission method during a handoff mode in a base station of a mobile communication system which transmits data in frame units, the transmission method comprising the steps of:

• preparing consecutive first and second frames;
• dividing each of the first and second frames into a first interval and a second interval following the first interval;
• and
• transmitting respective frame data in the first interval of the first frame and the second interval of the second frame and preventing transmission of the data in the second interval of the first frame and the first interval of the second frame.

A handoff method in a mobile communication system preparing consecutive first and second frames each divided into a first interval and a second interval succeeding the first interval and transmitting data in frame units, the handoff method comprising the steps of:

• transmitting frame data in the first interval of the first frame from a base station to a terminal;
• preventing, in the base station, transmission of the frame data in the second interval of the first frame and the first interval of the second frame;
• receiving, in the terminal, signals transmitted from other base stations to search for a base station to which the terminal is to be handed off;
• and
• transmitting frame data in the second interval of the second frame from the base station to the terminal.

A handoff method in a mobile communication system preparing consecutive first and second frames each divided into a first interval and a second interval succeeding the first interval and transmitting data in frame unit, the handoff method comprising the steps of:

• transmitting, to a terminal, handoff parameters for setting the first interval of the first frame and the second interval of the second frame to a data transmission interval and setting the second interval of the first frame and the first interval of the second frame to a data non-transmission interval, said step of transmitting being performed when it is necessary to perform a handoff operation while a base station communicates with the terminal;
• transmitting frame data in the first interval of the first frame from the base station to the terminal;
• preventing, in the base station, transmission of the frame data in the second interval of the first frame;
• receiving, in the terminal, signals transmitted from other base stations in the second interval of the first frame to search for a handoff target base station;
• transmitting a handoff target base station detection message from the terminal to the base station upon detection of a handoff target base station;
• preventing, in the base station, transmission of the frame data in the first interval of the second frame when the handoff target base station is not detected;
• receiving, in the terminal, signals transmitted from other base stations to search for a base station to which the terminal is to be handed off;
• transmitting frame data in the second interval of the second frame from the base station to the terminal;
• transmitting a handoff target base station detection message to the base station upon detection of the handoff target base station and performing a handoff procedure;
• and
• repeating the handoff procedure of the first and second frames when the handoff target base station is not detected.

A handoff device in a mobile communication system, comprising:

• a base station apparatus comprising;
• a first transmitter for transmitting frame data in a normal mode;
• a second transmitter having a rate converter for converting a data rate to increase the data rate, for transmitting the frame data in a handoff mode;
• a controller for transmitting the frame data of the first transmitter in the normal mode, having consecutive first and second frames each divided into a first interval and a second interval following the first interval, said controller transmitting respective frame data in the first interval of the first frame and the second interval of the second frame and preventing transmission of the data in the second interval of the first frame and the first interval of the second frame;
• a terminal apparatus comprising;
• a receiver for processing received data;
• a handoff determiner for analyzing a strength of the received signal to determine a handoff target base station;
• and
• a controller for applying, to the receiver, a signal transmitted from a present base station in the first interval of the first frame and the second interval of the second frame and applying, to the handoff determiner, a signal transmitted from other base stations in the second interval of the first frame and the first interval of the second frame.