MOBILE COMMUNICATION METHOD AND RADIO BASE STATION

• US 20120257602A1
• Filed: 11/02/2010
• Published: 10/11/2012
• Est. Priority Date: 11/02/2009
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Hapsari, Wuri Andarmawanti, Okamoto, Takeshi, Takahashi, Hideaki
• Granted Patent: US 8,693,438 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

Even when radio base stations including radio base station identification information eNB IDs having different lengths are coexistent, it is possible to perform an S1 handover. A mobile communication method according to the present invention includes a step of determining, a handover source radio base station eNB#0, whether a handover destination candidate radio base station is a macro cell radio base station eNB or a small cell radio base station HeNB with reference to a predetermined bit set in Cell ID included in E-CGI included in Measurement Report received from a mobile station UE.

Claims

1. A mobile communication method, which performs a handover process of a mobile station from a cell subordinate to a first radio base station to a cell subordinate to a second radio base station, comprising:

a step of determining, by the first radio base station, whether the second radio base station is a macro cell radio base station or a small cell radio base station with reference to predetermined information set in cell identification information capable of designating the cell subordinate to the second radio base station, which is included in a measurement report received from the mobile station;

a step of transmitting, by the first radio base station, a first handover request signal, in which a part of the cell identification information is set as identification information of the second radio base station, to a mobile switching center when it is determined that the second radio base station is the macro cell radio base station; and

a step of transmitting, by the first radio base station, a first handover request signal, in which the cell identification information is set, as is, as the identification information of the second radio base station, to the mobile switching center when it is determined that the second radio base station is the small cell radio base station.

2. The mobile communication method according to claim 1, wherein

the mobile switching center comprises a management unit configured to manage an entry including identification information of a radio base station and identification information of a tracking area, and

the mobile communication method comprises:

a step of transmitting, by the mobile switching center, a second handover request signal including the identification information of the tracking area to the gateway device if a length of the identification information of the second radio base station is a predetermined length and an entry including the identification information of the tracking area included in the first handover request signal is managed by the management unit even when an entry including the identification information of the second radio base station included in the first handover request signal has not been managed by the management unit; and

a step of transmitting, by the gateway device, a third handover request signal to the second radio base station designated by the tracking area included in the received second handover request signal and the identification information of the second radio base station, which corresponds to the identification information of the radio base station.

3. The mobile communication method according to claim 1, wherein

the mobile switching center comprises a management unit configured to manage an entry including identification information of a radio base station and identification information of a tracking area, and

the mobile communication method comprises:

a step of transmitting, by the mobile switching center, a handover failure signal to the first radio base station when an entry including the identification information of the second radio base station included in the first handover request signal has not been managed by the management unit and a length of the identification information of the second radio base station is not a predetermined length.

4. A radio base station, which serves as a first radio base station in a handover process of a mobile station from a cell subordinate to the first radio base station to a cell subordinate to a second radio base station, comprising:

a determination unit configured to determine whether the second radio base station is a macro cell radio base station or a small cell radio base station with reference to predetermined information set in cell identification information capable of designating the cell subordinate to the second radio base station, which is included in a measurement report received from the mobile station; and

a transmission unit configured to transmit a handover request signal, in which identification information of the second radio base station is set, to a mobile switching center, wherein

when the determination unit has determined that the second radio base station is the macro cell radio base station, the transmission unit is configured to transmit a handover request signal, in which a part of the cell identification information is set as the identification information of the second radio base station, to the mobile switching center, and

when the determination unit has determined that the second radio base station is the small cell radio base station, the transmission unit is configured to transmit a handover request signal, in which the cell identification information is set, as is, as the identification information of the second radio base station, to the mobile switching center.