Adaptive array antenna directivity control system

• US 20030069047A1
• Filed: 10/08/2002
• Published: 04/10/2003
• Est. Priority Date: 10/10/2001
• Status: Abandoned Application

• Current Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Original Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Inventors: Kitahara, Minako
• Application Number:
  US10/265,763
• Publication Number:
  US 20030069047A1
• Time in Patent Office: Days
• US Class Current: 455/562.1
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Abstract

To provide an adaptive array antenna directivity control system that can select a path optimum for communication depending on the state of communication with a mobile station, and improve an interference removing effect.

The adaptive array antenna directivity control system measures power values and arrival angles of signals of respective paths received at a plurality of antenna elements constituting an adaptive array antenna provided in a CDMA base station, selects a transmission wishing path based on the measurement results, executes a weight control relative to signals to be transmitted from the respective antenna elements based on the foregoing measurement results, and radio-outputs the signals as transmission signals.

Claims

1. An adaptive array antenna directivity control system that controls directivity of an adaptive array antenna provided in a radio base station, and causes signals from a mobile station received at a plurality of antenna elements constituting said adaptive array antenna, to have weights corresponding to the respective antenna elements so as to reduce interference relative to a reception wishing path optimum for receiving signals from said mobile station,

wherein paths are detected from the signals received at said antenna elements, a power value and an arrival angle are calculated for each of the detected paths, said reception wishing path is selected from said detected paths based on at least one of said power values and said arrival angles, the weight for reducing the interference relative to said reception wishing path is derived for each of said antenna elements, and the signals received at said antenna elements are multiplied by the corresponding weights.

2. An adaptive array antenna directivity control system according to claim 1, wherein, when the mobile station wishing communication performs low-speed communication, the reception wishing path is selected based on the power values in said paths and, when the mobile station performs high-speed communication, the reception wishing path is selected based on at least one of said power values and said arrival angles in said paths.

3. An adaptive array antenna directivity control system according to claim 1, wherein, when a power difference between the power value in the selected reception wishing path and the power value of the path having the greatest power value within the detected paths is no less than a predetermined value, the path having the greatest power value is selected as a new reception wishing path.

4. An adaptive array antenna directivity control system according to claim 2, wherein, when a power difference between the power value in the selected reception wishing path and the power value of the path having the greatest power value within the detected paths is no less than a predetermined value, the path having the greatest power value is selected as a new reception wishing path.

5. An adaptive array antenna directivity control system comprising:

a plurality of antenna receiving sections comprising a plurality of antenna elements constituting an adaptive array antenna, and receivers corresponding to said antenna elements, respectively, for receiving radio signals from a mobile station according to CDMA communication, converting the received radio signals into baseband signals, and outputting the baseband signals;

a received data processing section for detecting paths of the radio signals based on the baseband signals received at the antenna receiving sections, deriving a power value and an arrival angle relative to the corresponding antenna receiving section for each of the detected paths, selecting a reception wishing path optimum for receiving radio signals from said mobile station, from said detected paths based on at least one of said power values and said arrival angles, and outputting a result of the path detection, the power values and the arrival angles for the respective paths, and a result of the selection of the reception wishing path;

a weight control section for calculating a reception weight for each of said antenna receiving sections for reducing interference relative to the reception wishing path, based on the path detection result, the power value and the arrival angel for each path, and the selection result of the reception wishing path output from said received data processing section, and outputting the reception weights;

a plurality of multipliers provided for said antenna receiving sections, respectively, and implementing multiplication between the received signals output from the corresponding antenna receiving sections and the reception weights for the corresponding antenna receiving sections output from said weight control section; and

an adder for deriving the sum of multiplication results output from said respective multipliers, and outputting the sum as a received signal,

wherein said received data processing section comprises;

a path detecting section for performing despread processing relative to the baseband signals output from said antenna receiving sections, and detecting arrival timings of the signals received at the antenna receiving sections based on a result of the despread processing, thereby to detect said paths;

a power measuring section for calculating the power values for the respective paths based on signals after the despread processing;

an angle estimating section for estimating the arrival angles of the respective paths to the antenna receiving sections based on the signals after the despread processing; and

a path selecting section for selecting the reception wishing path optimum for receiving signals from the mobile station, from the detected paths based on at least one of said power values and said arrival angles.

6. An adaptive array antenna directivity control system according to claim 5, wherein, when the mobile station wishing communication performs low-speed communication, said path selecting section selects the reception wishing path based on the power values in said paths and, when the mobile station performs high-speed communication, said path selecting section selects the reception wishing path based on at least one of said power values and said arrival angles in said paths.

7. An adaptive array antenna directivity control system according to claim 5, wherein, when a power difference between the power value in the selected reception wishing path and the power value of the path having the greatest power value within the detected paths is no less than a predetermined value, said path selecting section selects the path having the greatest power value as a new reception wishing path.

8. An adaptive array antenna directivity control system according to claim 6, wherein, when a power difference between the power value in the selected reception wishing path and the power value of the path having the greatest power value within the detected paths is no less than a predetermined value, said path selecting section selects the path having the greatest power value as a new reception wishing path.

9. An adaptive array antenna directivity control system according to claim 7, wherein, when a reception characteristic of the adaptive array antenna is deteriorated, said path selecting section performs selection of a reception wishing path, and said weight control section calculates a reception weight for each of said antenna receiving sections based on a result of the selection, and outputs the reception weights to the corresponding multipliers.

10. An adaptive array antenna directivity control system according to claim 8, wherein, when a reception characteristic of the adaptive array antenna is deteriorated, said path selecting section performs selection of a reception wishing path, and said weight control section calculates a reception weight for each of said antenna receiving sections based on a result of the selection, and outputs the reception weights to the corresponding multipliers.

11. An adaptive array antenna directivity control system that controls directivity of an adaptive array antenna provided in a radio base station, and causes signals from a mobile station received at a plurality of antenna elements constituting said adaptive array antenna, to have weights corresponding to the respective antenna elements so as to reduce interference relative to a transmission wishing path optimum for transmitting signals to said mobile station,

wherein paths are detected from the signals received at said antenna elements, a power value and an arrival angle are calculated for each of the detected paths, said transmission wishing path is selected from said detected paths based on at least one of said power values and said arrival angles, the weight for reducing the interference relative to said transmission wishing path is derived for each of said antenna elements, and the signals to be transmitted from said antenna elements are multiplied by the corresponding weights.

12. An adaptive array antenna directivity control system according to claim 11, wherein, when the mobile station wishing communication performs low-speed communication, the transmission wishing path is selected based on the power values in said paths and, when the mobile station performs high-speed communication, the transmission wishing path is selected based on at least one of said power values and said arrival angles in said paths.

13. An adaptive array antenna directivity control system according to claim 11, wherein, when a power difference between the power value in the selected transmission wishing path and the power value of the path having the greatest power value within the detected paths is no less than a predetermined value, the path having the greatest power value is selected as a new transmission wishing path.

14. An adaptive array antenna directivity control system according to claim 12, wherein, when a power difference between the power value in the selected transmission wishing path and the power value of the path having the greatest power value within the detected paths is no less than a predetermined value, the path having the greatest power value is selected as a new transmission wishing path.

15. An adaptive array antenna directivity control system comprising:

a plurality of antenna transmitting/receiving sections comprising a plurality of antenna elements constituting an adaptive array antenna, and transmitters and receivers corresponding to said antenna elements, respectively, for receiving radio signals from a mobile station according to CDMA communication, converting the received radio signals into baseband signals, and outputting the baseband signals, while converting baseband signals to be transmitted into radio signals and transmitting the radio signals;

a received data processing section for detecting paths of the radio signals based on the baseband signals received at the antenna transmitting/receiving sections, deriving a power value and an arrival angle relative to the corresponding antenna transmitting/receiving section for each of the detected paths, selecting a transmission wishing path optimum for transmitting radio signals to said mobile station, from said detected paths based on at least one of said power values and said arrival angles, and outputting a result of the path detection, the power values and the arrival angles for the respective paths, and a result of the selection of the transmission wishing path;

a weight control section for calculating a transmission weight for each of said antenna transmitting/receiving sections for reducing interference relative to the transmission wishing path, based on the path detection result, the power value and the arrival angel for each path, and the selection result of the transmission wishing path output from said received data processing section, and outputting the transmission weights;

a distributor for distributing and outputting baseband transmission signals to be transmitted, for said antenna transmitting/receiving sections, respectively; and

a plurality of multipliers provided for said antenna transmitting/receiving sections, respectively, implementing multiplication between the transmission signals output from said distributor and the transmission weights for the corresponding antenna transmitting/receiving sections output from said weight control section, and outputting multiplication results to the corresponding antenna transmitting/receiving sections,

wherein said received data processing section comprises;

a path detecting section for performing despread processing relative to the baseband signals output from said antenna transmitting/receiving sections, and detecting arrival timings of the signals received at the antenna transmitting/receiving sections based on a result of the despread processing, thereby to detect said paths;

a power measuring section for calculating the power values for the respective paths based on signals after the despread processing;

an angle estimating section for estimating the arrival angles of the respective paths to the antenna transmitting/receiving sections based on the signals after the despread processing; and

a path selecting section for selecting the transmission wishing path optimum for transmitting signals to the mobile station, from the detected paths based on at least one of said power values and said arrival angles.

16. An adaptive array antenna directivity control system according to claim 15, wherein, when the mobile station wishing communication performs low-speed communication, said path selecting section selects the transmission wishing path based on the power values in said paths and, when the mobile station performs high-speed communication, said path selecting section selects the transmission wishing path based on at least one of said power values and said arrival angles in said paths.

17. An adaptive array antenna directivity control system according to claim 15, wherein, when a power difference between the power value in the selected transmission wishing path and the power value of the path having the greatest power value within the detected paths is no less than a predetermined value, said path selecting section selects the path having the greatest power value as a new transmission wishing path.

18. An adaptive array antenna directivity control system according to claim 16, wherein, when a power difference between the power value in the selected transmission wishing path and the power value of the path having the greatest power value within the detected paths is no less than a predetermined value, said path selecting section selects the path having the greatest power value as a new transmission wishing path.

19. An adaptive array antenna directivity control system according to claim 17, wherein, when a transmission characteristic of the adaptive array antenna is deteriorated, said path selecting section performs selection of a transmission wishing path, and said weight control section calculates a transmission weight for each of said antenna transmitting/receiving sections based on a result of the selection, and outputs the transmission weights to the corresponding multipliers.

20. An adaptive array antenna directivity control system according to claim 18, wherein, when a transmission characteristic of the adaptive array antenna is deteriorated, said path selecting section performs selection of a transmission wishing path, and said weight control section calculates a transmission weight for each of said antenna transmitting/receiving sections based on a result of the selection, and outputs the transmission weights to the corresponding multipliers.