METHOD AND SYSTEM FOR SELECTING AN ANTENNA BEAM OF A BASE STATION OF RADIO SYSTEM

• US 20020034943A1
• Filed: 11/20/1998
• Published: 03/21/2002
• Est. Priority Date: 05/22/1996
• Status: Active Grant

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: PALLONEN, JORMA
• Granted Patent: US 6,408,169 B1
• Time in Patent Office: Days
• US Class Current: 455/424
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• 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 76/10 Connection setup

Abstract

The present invention relates to a base station of a radio system whose antenna means (11) include means (6 to 8) for receiving signals associated with the same logical channel by at least two antenna beams (1 to 4), measuring means (8) for measuring the signal level of the signals received by the antenna beams, and control means (8) for selecting one or more antenna beams (1 to 4) and for supplying the signals of the selected antenna beam to a receiver unit (5) of the base station (BTS1). In order that the best possible signal would be definitely transmitted to the base station, the base station (BTS1) comprises means for measuring the quality of the signals and for generating a quality signal (BER) and for supplying it to the control means (8), and the control means (8) are arranged to select an antenna beam (1 to 4) on the basis of the signal level measured by the measuring means and the quality signal (BER) supplied to the control means.

Claims

1. A method for selecting an antenna beam of a base station of a radio system from among two or more optional antenna beams, which antenna beams are arranged to receive signals associated with the same logical channel, in which method

antenna means of the base station are provided with measuring means for measuring the signal level of a received signal, the signal level (A, B) of the signals received by different antenna beams is measured and the antenna beam that has received the signals (C) with the strongest signal strength is selected for use, and

the signals received by the selected antenna beam are supplied further to a receiver unit of the base station situated at a distance from the antenna means, characterized by

monitoring the quality (D) of the signals received by the receiver unit of the base station by means of said selected antenna beam, and

selecting some other antenna beam (F) for use in place of the first selected antenna beam if the quality of the signals received by the receiver unit falls below a predetermined reference level.

2. A method according to claim 1, characterized in that signal quality is monitored by monitoring the signal noise ratio, the bit error ratio or the quality class of the signal received by the receiver-unit.

3. A base station of a radio system whose antenna means (11) include:

means (6 to 8) for receiving signals associated with the same logical channel by at least two antenna beams (1 to 4),

measuring means (8) for measuring the signal level of the signals received by the antenna beams, and

control means (8) for selecting one or more antenna beams (1 to 4) and for supplying the signals received by means of the selected antenna beam or antenna beams further to a receiver unit (5) of the base station (BTS1) arranged at a distance from the antenna means, characterized in that

the base station (BTS1) comprises means for measuring the quality of the signals received by the receiver unit from the antenna means (11) and for generating a quality signal (BER) responsive to the quality of the signals and for supplying it to the control means (8), and

that the control means (8) are arranged to select said one or more antenna beams (1 to 4) on the basis of the signal level measured by the measuring means and the quality signal (BER) supplied to the control means.

4. A base station according to claim 3, characterized in that the control means (8) are arranged to an antenna mast of the base station in the immediate vicinity of an antenna element or antenna elements.

5. A base station according to claim 3, characterized in that the control means (8) are arranged to select the antenna beam (1 to 4) or antenna beams having received the signals with the strongest signal strength when the quality signal (BER) indicates that the received signals are of a good quality, and that the control means (8) are arranged to select for use the antenna beam having received the signals with the next strongest signal strength when the quality signal (BER) indicates that the signals received by means of the first selected antenna beam are of a poor quality.

6. A base station according to claim 3, characterized in that said quality signal (BER) is responsive to the signal noise ratio, the bit error ratio or the quality class measured by the base station.

7. A base station according to claim 3, characterized in that the frequency channels of the radio system are divided by the TDMA principle into logical channels, in which case the base station (BTS1) comprises means for generating a clock signal (CLK) indicating a change of time slots and for supplying it to the control means (8), and

that the control means (8) include memory means (14) for storing the information included in the quality signal (BER) separately for each time slot, in which case the control means are responsive to the clock signal (CLK) for retrieving the information stored into the memory means (14) for a specific time slot and for utilizing the retrieved information in the selection of the antenna beam (1 to 4) when the clock signal (CLK) indicates it is the turn of a new time slot to receive.

8. A base station according to claim 3, characterized in that the control means (8) include data processing means for maintaining a log for each antenna beam at least of the frequency channels and the time when with a specified antenna beam (1 to 4) the signal level measured by the measuring means exceeds a specified limit and the quality signal (BER) supplied to the control means (8) indicates that the received signals fall below the specified quality level, whereby in addition to the signal level measured by the measuring means and the quality signal supplied to them, the control means (8) are arranged to take into account information recorded in the log in the selection of said one or more antenna beams (1 to 4) in such a manner that the control means select the antenna beam whose quality level exceeds a specified reference level on the basis of the statistics at the moment in question and on the frequency channel in question.

9. A cellular radio system including

a base station (BTS1) comprising antenna means (11) arranged at a distance from the base station for receiving radio signals associated with the same logical channel by at least two antenna beams (1 to 4), measuring means for measuring the signal level of the signals received by the antenna beams, and control means (8) for selecting one or more antenna beams (1 to 4) and for supplying the signals received by means of the selected antenna beam or antenna beams further to a receiver unit (5) of the base station, and

a network management centre (O&

M) connected by means of a data transmission connection (15) to the base station (BTS1), characterized in that

the base station (BTS1) comprises means for measuring the quality of the signals received by the receiver unit (5) from the antenna means (11) and for generating a quality signal (BER) responsive to the quality of the signals and for supplying it to the control means (8), in which case the control means are arranged to select said one or more antenna beams (1 to 4) on the basis of the signal level measured by the measuring means and the quality signal (BER) supplied to the control means,

that the base station (BTS1) comprises means for sending information representing the signal level (RSSI) of the received signals and the quality of the signals (BER) received by the receiver unit separately for each antenna beam to the network management centre (O&

M) by means of said data transmission connection (15), and

that the network management centre (O&

M) includes data processing means (16) for processing data received from the base station (BTS1) to find out the disturbance level in the environment of the base station (BTS1).