Radio communication system and base station

• US 7,996,033 B2
• Filed: 03/31/2008
• Issued: 08/09/2011
• Est. Priority Date: 06/25/2004
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi Communication Technologies, Ltd. (Hitachi, Ltd.)
• Inventors: Mazawa, Shiro, Usuba, Keiji, Kawamoto, Kiyoshi, Yoshida, Akihiko, Takahashi, Yosuke
• Primary Examiner(s): LEE, JOHN J
• Application Number:
  US12/059,046
• Publication Number:
  US 20080182612A1
• Time in Patent Office: 1,226 Days
• Field of Search: 455/414.3, 455/415, 455/456.2, 455/432.2, 455/422.1, 455/446, 455/414.2, 455/442, 455/524, 455/525, 455/3.01, 455/424, 455/426.1, 455/426.2, 455/435.1, 455/435.2, 455/561, 370/352, 370/395.2, 709/227
• US Class Current: 455/525
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection

Abstract

A radio communication system includes a grouping unit for grouping a plurality of base stations into a plurality of groups (Soft Handoff Groups) and a determining unit for selecting base stations belonging to one and the same group selected from the groups produced by the grouping unit and for determining the base stations as base stations to send communication packets to an access terminal.

Claims

1. In a radio communication system including a plurality of base stations, a communication controller connecting the plurality of base stations with a communication network, and a contents server connected to the communication network, wherein each base station is associated with a plurality of sectors, the base station comprising:

a sector state managing table for storing group numbers, each group number being associated with the sectors of the base station and with sectors of other base stations that are adjacent to one of the sectors of the base station, wherein base stations of the sectors associated with said each group number are configured to transmit identical communication information to an access terminal at substantially the same timing; and

a control unit,

wherein, when the control unit receives a viewing request from the access terminal, the control unit establishes a path to the communication controller, obtains the communication information from the contents server via the communication controller to start transmission thereof to the access terminal from a first sector of the base station, and transmits a communication information transmission request to sectors adjacent to the first sector using based on information in the sector state managing table, wherein the communication information transmission request includes at least an ID of the communication information, an ID of the first sector, and the group number associated with the first sector, and

wherein, when the control unit receives another communication information transmission request from another base station, the control unit refers to the sector state managing table, when the group number of the sector that received said another communication information transmission request coincides with the group number included in said another communication information transmission request, then the control unit establishes a path to the communication controller, and obtains communication information specified in said another communication information transmission request from the contents server via the communication controller to start transmission thereof to the access terminal.

2. In a radio communication system including a plurality of base stations, a communication controller connecting the plurality of base stations with a communication network, and a contents server connected to the communication network, in which the plurality of base stations transmit communication information to an access terminal at substantially the same timing, wherein the access terminal combines the communication information received from the plurality of base stations, wherein each base station is associated with a plurality of sectors, the base station comprising:

a table comprising sector identifiers (IDs) of sectors of the base station and sectors of other base stations adjacent thereto, a parameter that is associated with each of the sector IDs, the parameter being used to determine whether a communication information transmission request is transmitted to a sector associated with the parameter; and

a control unit,

wherein, during transmission of the communication information to the access terminal, when the control unit receives an addition request of the communication information from the access terminal, wherein the addition request includes at least an ID of a first sector selected by the access terminal based on the positional information of the access terminal, positional information of the base station, and the parameter, then the control unit transmits the communication information transmission request to the first sector whose ID is included in the addition request, the communication information transmission request including at least an ID of the communication information and an ID of the sector that is transmitting the communication information transmission request,

wherein, when the control unit receives another communication information transmission request from another base station, then the control unit establishes a path to the communication controller, and obtains the communication information specified in said another communication information transmission request from the contents server via the communication controller to start transmission of the communication information to the access terminal.

3. The base station in accordance with claim 2, wherein the parameter is distance to the access terminal.

4. In a radio communication system including a plurality of base stations, a communication controller connecting the plurality of base stations with a communication network, and a contents sever connected to the communication network, wherein communication information is transmitted by at least some of the base stations to an access terminal at substantially the same timing and the access terminal combines the communication information received from said at least some of the base stations, wherein each base station is associated with a plurality of sectors, each base station including:

a table for storing, for each of sectors of the base station and of other base stations that are adjacent to the sectors of the base station, a sector ID for identifying said each sector, a corresponding parameter, and corresponding positional information, the parameter being used to determine whether or not communication information transmission request is sent to the corresponding sector; and

a control unit,

wherein, during transmission of the communication information to the access terminal from said at least some of the base stations, when the control unit receives an addition request of the communication information from the access terminal, the control unit sends the communication information transmission request to sectors adjacent to a first sector of the base station that received the addition request, the communication information transmission request including at least an ID of the communication information and an ID of the first sector, the positional information of the base station, and the parameter corresponding to the first sector,

wherein, when the control unit receives another communication information transmission request from another base station, the control unit refers to the table, calculates a distance between the base station and the other base station using the positional information of the other base station included in said another communication information transmission request and the positional information of the base station, compares the calculation result with the parameter, when the calculation result is smaller than the parameter, then the control unit establishes a path to the communication controller, obtains the communication information specified in said another communication information transmission request from the contents server via the communication controller to start transmission of the communication information to the access terminal.