Radio base station apparatus and base station controller

A radio communication method comprising:

• maintaining identification information allotted to a radio terminal for receiving data without renewing the identification information when the radio terminal moves from an area of a first radio base station to an area of a second radio base station, and transmitting data and the identification information to the radio terminal from the first and second radio base stations in a diversity transmission manner;
• and
• renewing the identification information when the radio terminal moves to an area of a third base station, and transmitting data and the renewed identification information to the radio terminal from the third radio base station, wherein
• the third base station belongs to a mobile zone which is different from a mobile zone which the first and second base stations using the diversity transmission manner belong to.

A radio system performing radio communication with a radio terminal comprising:

• a second radio base station maintaining identification information allotted to the radio terminal for receiving data without renewing the identification information when the radio terminal moves from an area of a first radio base station to an area of the second radio base station, and transmitting data and the identification information to the radio terminal from the first and second radio base stations in a diversity transmission manner;
• and
• a third base station renewing the identification information when the radio terminal moves to an area of the third base station, and transmitting data and the renewed identification information to the radio terminal from the third radio base station, wherein
• the third base station belongs to a mobile zone which is different from a mobile zone which the first and second base stations using the diversity transmission manner belong to.

A radio terminal performing radio communication with radio base stations comprising:

• a second radio base station maintaining identification information allotted to the radio terminal for receiving data without renewing the identification information when the radio terminal moves from an area of a first radio base station to an area of the second radio base station, and transmitting data and the identification information to the radio terminal from the first and second radio base stations in a diversity transmission manner;
• and
• a third base station renewing the identification information when the radio terminal moves to an area of the third base station, and transmitting data and the renewed identification information to the radio terminal from the third radio base station, wherein
• the third base station belongs to a mobile zone which is different from a mobile zone which the first and station base stations using the diversity transmission manner belong to.