Method of determining transmission direction, and a radio system

• US 6,144,340 A
• Filed: 11/12/1999
• Issued: 11/07/2000
• Est. Priority Date: 05/16/1997
• Status: Expired due to Term

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Networks (Nokia Corporation)
• Inventors: Keskitalo, Iikka, Kiiski, Matti, Vikamaa, Sakari
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/439,624
• Time in Patent Office: 361 Days
• Field of Search: 342/368, 342/371, 342/373, 455/422, 455/424-426
• US Class Current: 342/371
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0695 using beam selection

Abstract

The invention relates to a radio system and a method of determining the transmission direction. The radio system comprises at least one base station communicating with terminals within its area by emitting a radiation pattern extending over the whole cell area and directional radiation patterns covering only part of the cell area. The base station transmits base-station-related information on a common control channel to the terminals. In the solution of the invention, the base-station-related information transmitted by the base station comprises a general part and a beam-specific part. The base station uses the radiation pattern extending over the whole cell area when transmitting the general part. Each beam-specific part is transmitted by using a specific radiation pattern. The terminal detects one of more beam-specific parts from the information received from the base station and transmits information about the detection result to the base station, on the basis of which the base station decides which directional radiation pattern to use when communicating with the terminal. The invention enables fast determination of the terminal direction with respect to the base station.

Claims

1. A method of determining the transmission direction in a radio system comprising at least one base station (100) communicating with terminals (102-106) within its area by emitting a radiation pattern extending over the whole cell area (110) and directional radiation patterns covering only part of the cell area (112-116), and that the base station transmits base-station-related information on a common control channel to the terminals, characterized in that

the base-station-related information transmitted by the base station comprises a general part and a beam-specific part, and that

the base station uses the radiation pattern (110) extending over the whole cell area when transmitting the general part, and that

each beam-specific part is transmitted by using a specific radiation pattern (112-116), and that

the terminal detects one or more beam-specific parts from the information received from the base station and transmits information about the detection result to the base station, and that

the base station decides, on the basis of the information, which directional radiation pattern to use when communicating with the terminal.

2. A method as claimed in claim 1, characterized in that the beam-specific part of the base-station-related information transmitted by the base station comprises a code that is different in each directional radiation pattern transmitted by the base station.

3. A method as claimed in claim 1, characterized in that the terminal transmits information to the base station about one or more detected beam-specific identifiers.

4. A method as claimed in claim 1, characterized in that the base station transmits base-station-related information in frame-structured form, and that the frame comprises a general part and a beam-specific part, and that

the base station uses the radiation pattern extending over the whole cell area when transmitting the general part of the frame, and that

each beam-specific part of the frame is transmitted by using a specific directional radiation pattern.

5. A method as claimed in claim 4, characterized in that the frame comprises a training sequence used as the beam-specific part.

6. A method as claimed in claim 1, characterized in that the base station forms the radiation pattern extending over the whole cell area and the directional radiation patterns by means of an antenna array composed of several elements by phasing the signal to be transmitted via the antennas.

7. A method as claimed in claim 1, characterized in that the directional radiation patterns are narrowbeam radiation patterns.

8. A method as claimed in claim 1, characterized in that code division multiple access is used in the system.

9. A method as claimed in claim 8, characterized in that each beam-specific part is composed of a different spreading code.

10. A method as claimed in claim 8, characterized in that the general part and the beam-specific parts are transmitted by using the same spreading code, but in different phases.

11. A radio system comprising at least one base station communicating with terminals within its area, which base station comprises means (232a, 232b, 234) for emitting a radiation pattern extending over the whole cell area and directional radiation patterns covering only part of the cell area, and means (232a, 232b, 234, 220) for transmitting base-station-related information on a common control channel to the terminals, characterized in that

the base station is arranged to transmit base-station-related information comprising a general part and a beam-specific part, and that

the base station comprises means (232a, 232b, 234) for using the radiation pattern extending over the whole cell area when transmitting the general part and

means (232a, 232b, 234) for transmitting each beam-specific part by using a specific directional radiation pattern, and that

the terminal comprises means (716, 718) for detecting one or more beam-specific parts from the information received from the base station and means (702-706, 718) for transmitting information about the detection result to the base station, and that

the base station comprises means (218, 234) for deciding, on the basis of the information, which directional radiation pattern to use when communicating with the terminal.

12. A radio system as claimed in claim 11, characterized in that the base station comprises an antenna array (200a, 200b, 232a, 232b) composed of several elements, and means (218, 234) for phasing the signal transmitted via the antennas in order to form the directional radiation patterns.

13. A radio system as claimed in claim 11, characterized in that the base station comprises means (220, 234) for forming the beam-specific part of the base-station-related information in such a way that it comprises a code that is different in each directional radiation pattern transmitted by the base station.