Directional beam communication system, directional beam communication method, base station and controller

• US 20040185783A1
• Filed: 12/19/2003
• Published: 09/23/2004
• Est. Priority Date: 12/19/2002
• 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, Umesh, Anil, Tanaka, Shinya, Okawa, Koichi
• Granted Patent: US 7,233,812 B2
• Time in Patent Office: Days
• US Class Current: 455/63.4
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

The object of the present invention to provide a directional beam communication system whereby the beam width of a directional beam to be transmitted is reduced by sharing an array antenna among a plurality of adjacent sectors so as to increase the interference suppression effect. The directional beam communication system is configured to communicate with a mobile station MS located in a service area formed by a plurality of sectors S1 and S2 using a directional beam which is transmitted by an array antenna A including a plurality of antenna elements a. The array antenna A for transmitting the directional beam is shared among at least two adjacent sectors S1 and S2.

Claims

1. A directional beam communication system for communicating with a mobile station located in a service area formed by a plurality of sectors using a directional beam which is transmitted by an array antenna including a plurality of antenna elements, wherein

the array antenna for transmitting the directional beam is shared among at least two adjacent sectors.

2. A directional beam communication method for communicating with a mobile station located in a service area formed by a plurality of sectors using a directional beam which is transmitted by an array antenna including a plurality of antenna elements, wherein

the array antenna for transmitting the directional beam is shared among at least two adjacent sectors.

3. A base station for communicating with a mobile station located in a service area formed by a plurality of sectors using a directional beam which is transmitted by an array antenna including a plurality of antenna elements, wherein

the array antenna for transmitting the directional beam is shared among at least two adjacent sectors.

4. The base station according to claim 3 comprising:

a receiver configured to acquire reception quality information for a common channel which is measured by the mobile station; and

a spreading modulator configured to perform a spreading modulation using a scrambling code, the scrambling code being assigned to downlink dedicated channels of the mobile station according to the location of the mobile station specified by the reception quality information.

5. The base station according to claim 4, wherein

the common channel is transmitted by a sector antenna installed independently of the array antenna, the sector antenna being installed for said each sector.

6. The base station according to claim 3 comprising:

a DOA estimator configured to estimate the direction of arrival of a signal transmitted from the mobile station; and

a spreading modulator configured to perform a spreading modulation using a scrambling code, the scrambling code being assigned to downlink dedicated channels of the mobile station according to the location of the mobile station specified by the direction of arrival.

7. A controller for controlling a base station for communicating with a mobile station located in a service area formed by a plurality of sectors using a directional beam which is transmitted by an array antenna including a plurality of antenna elements, the controller comprising:

a location specifier configured to specify the location of the mobile station in accordance with a reception quality of a common channel in the mobile station or the direction of arrival of a signal transmitted from the mobile station;

a scrambling code assigner configured to assign a scrambling code to downlink dedicated channels of the mobile station; and

a notifier configured to notify the assigned scrambling code to the base station.