Mobile communication system, mobile station and diversity handover branch control method

• US 7,570,950 B2
• Filed: 10/31/2006
• Issued: 08/04/2009
• Est. Priority Date: 06/04/1997
• Status: Expired due to Fees

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Sato, Takaaki, Tamura, Motoshi, Ohtani, Tomoyuki
• Primary Examiner(s): Cumming; William D
• Application Number:
  US11/555,174
• Publication Number:
  US 20070058589A1
• Time in Patent Office: 1,008 Days
• Field of Search: 455/503, 455/343.1, 455/424, 455/436, 455/437, 455/442, 455/456.1, 455/56.2, 370/252, 370/331
• US Class Current: 455/436
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/28 involving a plurality of connections, e.g. multi-call or multi-bearer connections
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 92/04 Interfaces between hierarchically different network devices
• CPC Class Codes: H04W 92/20 between access points
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A branch candidate selecting method by a mobile station and a diversity handover control method on a network side in DHO performance are provided which consider a maximum cable branch number and maximum radio branch number of the mobile station, when the mobile station detects the plurality of addition branch candidates and deletion branch candidates. The mobile station inserts a plurality of addition branch candidates and deletion branch candidates, that is, all the DHO candidates into one handover trigger signal, and notifies the network. The addition branch candidates are put into addition information parameters in the handover trigger signal, and the deletion branch candidates are put into deletion information parameters. To simplify processing on the network side, the network side separates the addition branch candidates from the deletion branch candidates, and carries out sequential processing of them independently.

Claims

1. A candidate base station notification method using in a handover controlling a communication between a mobile station and at least one base station, in a wireless communication system including the mobile station and a plurality of base stations, said method comprising:

an act of comparing an active threshold with a quality of a signal transmitted from a base station that is an addition candidate, said active threshold being greater than an addition threshold used to categorize the base station as the addition candidate, the active threshold being determined in accordance with a quality of a signal transmitted from one or more active base stations; and

in response to the act of comparing, an act of notifying at least one of the one or more active base stations of information about the addition candidate whose signal quality is greater than the active threshold in accordance with a result of the act of comparing;

wherein said act of notifying transmits information including the quality of the signal transmitted from the addition candidate.

2. A candidate base station notification method according to claim 1, further comprising:

performing a handover process by adding a wired or fixed wireless connection between at least one base station and the addition candidate before commencing the transmission from the addition candidate,

wherein said at least one base station is performing a communication with the mobile station.

3. A candidate base station notification method using in a handover controlling a communication between a mobile station and at least one base station, in a wireless communication system including the mobile station and a plurality of base stations, said method comprising:

an act of comparing a deletion threshold with a quality of a signal transmitted from a base station, said deletion threshold being determined in accordance with a quality of a signal transmitted from one or more active base stations; and

in response to the act of comparing, an act of notifying at least one of the one or more active base stations of information about the deletion candidate whose signal quality is less than the deletion threshold in accordance with a result of the act of comparing;

wherein said act of notifying transmits information including the quality of the signal transmitted from the deletion candidate.

4. A candidate base station notification method according to claim 3, further comprising:

performing a handover process by deleting a wired or fixed wireless connection between at least one base station and the deletion candidate after stopping the transmission from the deletion candidate,

wherein said at least one base station is performing a communication with the mobile station.