Base station connection method, radio network controller, and mobile station

• US 20040023693A1
• Filed: 07/29/2003
• Published: 02/05/2004
• Est. Priority Date: 08/01/2002
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Nakamura, Takehiro, Tanaka, Shinya, Okawa, Koichi
• Granted Patent: US 7,190,957 B2
• Time in Patent Office: Days
• US Class Current: 455/562.1
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node

Abstract

A method for connecting the radio link between a mobile station and a base station is provided to improve quality of received signals at the base station and the mobile station. A radio network controller (RNC) monitors the difference between the reception power of signals from the source base station BS1 and the destination base station BS2. If the base station BS2 is incapable of directional beam signal transmission and reception, and when the reception power difference becomes smaller than a first handover threshold, the radio network controller adds the base station BS2 as a radio link connection destination of the mobile station. If the base station BS2 is capable of directional beam signal transmission and reception, and when the reception power difference becomes smaller than a second handover threshold, which is larger than the first handover threshold, the radio network controller adds the base station BS2 as a radio link connection destination of the mobile station.

Claims

1. A method of connecting a mobile station with a base station via a radio link in a mobile communication system including a first base station capable of directional beam signal transmission and reception and a second base station incapable of directional beam signal transmission and reception, the method comprising the step of:

preferentially connecting the mobile station to the first base station rather than to the second base station.

2. The method as claimed in claim 1, wherein the step of preferentially connecting the mobile station to the first base station includes a step of:

setting different handover threshold values for connecting and disconnecting the mobile station with the first base station and the second station, respectively, when the mobile station undergoes handover.

3. The method as claimed in claim 1, wherein the step of preferentially connecting the mobile station to the first base station includes a step of:

setting different threshold values for connecting and disconnecting the mobile station with the first base station and the second station, respectively, when the mobile station is on standby and switches a connection destination thereof.

4. A radio network controller for controlling a radio link connection between a mobile station and a base station in a mobile communication system including a first base station capable of directional beam signal transmission and reception and a second base station incapable of directional beam signal transmission and reception, the radio network controller comprising:

a base station connection control unit configured to preferentially connect the mobile station to the first base station rather than to the second base station.

5. The radio network controller as claimed in claim 4, wherein

the base station connection control unit sets different handover threshold values for connecting and disconnecting the mobile station with the first base station and the second station, respectively.

6. The radio network controller as claimed in claim 5, wherein

the handover threshold value is defined as an absolute value of a difference between power of signals from a handover source base station and power of signals from a handover destination base station, and

the handover threshold value for connecting the mobile station with the first base station is larger than the handover threshold value for connecting the mobile station with the second base station,

7. The radio network controller as claimed in claim 5, wherein

the handover threshold value is defined as an absolute value of a difference between power of signals from a handover source base station and power of signals from a handover destination base station, and

the handover threshold value for disconnecting the mobile station and the first base station is larger than the handover threshold value for disconnecting the mobile station and the second base station.

8. A mobile station in a mobile communication system including a first base station capable of directional beam signal transmission and reception and a second base station incapable of directional beam signal transmission and reception, the mobile station comprising:

a base station connection unit configured to preferentially connect the mobile station to the first base station rather than to the second base station.

9. The mobile station as claimed in claim 8, wherein

the base station connection unit sets different threshold values for connecting and disconnecting the mobile station with the first base station and the second station, respectively, when the mobile station is on standby and switches a connection destination thereof.

10. The mobile station as claimed in claim 9, wherein

the threshold value is defined as an absolute value of a difference between power of signals from a switching source base station and power of signals from a switching destination base station, and

the threshold value for switching to the first base station is smaller than the threshold value for switching to the second base station.

11. The mobile station as claimed in claim 9, wherein

the threshold value is defined as an absolute value of a difference between power of signals from a switching source base station and power of signals from a switching destination base station, and

the threshold value for switching from the first base station is larger than the threshold value for switching from the second base station.

12. The mobile station as claimed in claim 8, further comprising:

a base station determination unit configured to identify and distinguish the first base station from the second base station.

13. The mobile station as claimed in claim 9, further comprising:

a threshold value receiver configured to receive the threshold values.