Controller For Selecting Antenna For Multiple-Input/Multiple-Output Communication

• US 20090239523A1
• Filed: 06/02/2009
• Published: 09/24/2009
• Est. Priority Date: 12/14/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Miyamoto, Shoichi
• Granted Patent: US 8,565,825 B2
• Time in Patent Office: Days
• US Class Current: 455/422.100
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0495 using overlapping sectors in the same base station to implement MIMO for antennas
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas

Abstract

A base station apparatus for performing radio communication with a mobile station in a cell having a plurality of sectors performs a MIMO transmission using an antenna selected from among the antennas provided in each of two sectors when the mobile station moves in the vicinity of the boundary between the sectors. A base station apparatus for performing the radio communication with a mobile station in a cell having no sector structure performs a MIMO transmission using two or more antennas selected from among the antennas when the mobile station moves.

Claims

1. A base station apparatus which performs radio communications in a multiple-input/multiple-output transmission with a mobile station in a cell having a plurality of sectors, the base station apparatus comprising:

one or more antennas provided for each of the plurality of sectors; and

a control unit to select an antenna from among the antennas provided for each of two sectors when the mobile station moves in a vicinity of a boundary of the two sectors, and select a multiple-input/multiple-output transmission using the selected antennas.

2. The base station apparatus according to claim 1, wherein

the control unit compares quality information of a signal received by the mobile station from each antenna with a threshold, selects the antennas used in the multiple-input/multiple-output transmission from among the antennas having the quality information exceeding the threshold in the two sectors, and selects a transmission by a fast cell selection or soft handover unless there is a plurality of antennas having the quality information exceeding the threshold.

3. The base station apparatus according to claim 2, wherein

the control unit adjusts the threshold according to information about a Doppler frequency or a delay spread of the signal received by the mobile station from each antenna.

4. The base station apparatus according to claim 1, wherein:

the control unit includes a first scheduler to manage an antenna of a sector from which the mobile station moves, and a second scheduler to manage an antenna of a sector to which the mobile station moves;

the first scheduler inquires of the second scheduler about whether or not an antenna of the sector to which the mobile station moves is available, and selects a multiple-input/multiple-output transmission using the antenna of the sector to which the mobile station moves if the antenna of the sector to which the mobile station moves is available.

5. A base station apparatus which performs radio communications in a multiple-input/multiple-output transmission with a mobile station in a cell having no sector configuration, the base station apparatus comprising:

a plurality of antennas provided corresponding to the cell; and

a control unit to select two or more antennas from among the plurality of antennas when the mobile station moves, and select a multiple-input/multiple-output transmission using the selected antennas.

6. The base station apparatus according to claim 5, wherein

the control unit compares quality information of a signal received by the mobile station from each antenna with a threshold, selects an antenna used in the multiple-input/multiple-output transmission from among the antennas having the quality information exceeding the threshold.

7. The base station apparatus according to claim 6, wherein

the control unit adjusts the threshold according to information about a Doppler frequency or a delay spread of the signal received by the mobile station from each antenna.

8. The base station apparatus according to claim 5, wherein:

the control unit comprises a first scheduler to manage an antenna in communications with the mobile station in the plurality of antennas, and a second scheduler to manage a newly selected antenna;

the first scheduler inquires of the second scheduler whether or not the newly selected antenna is available, and selects a multiple-input/multiple-output transmission using the newly selected antenna if the newly selected antenna is available.

9. A communication method for performing radio communications in a multiple-input/multiple-output transmission with a mobile station in a cell having a plurality of sectors, comprising:

selecting an antenna from among antennas provided for each of two sectors when a mobile station moves in a vicinity of a boundary of the two sectors; and

performing a multiple-input/multiple-output transmission using the selected antennas.