Digital combiner for phased-array RF receivers

• US 9,473,181 B1
• Filed: 12/10/2015
• Issued: 10/18/2016
• Est. Priority Date: 12/10/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Takano, Kohji, Nakano, Daiju, Kohda, Yasuteru
• Primary Examiner(s): Pham, Tuan
• Application Number:
  US14/965,566
• Time in Patent Office: 313 Days
• Field of Search: 455/130, 455/278.1, 455/280, 455/296
• US Class Current: 1/1
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0868 Hybrid systems, i.e. switching and combining

Abstract

Methods and systems for receiving radio frequency (RF) signals include adjusting a digital baseband signal from a first RF front-end to compensate for errors based on a correlation value from a first Golay correlator. A set of digital baseband signals from a set of respective additional RF front-ends is adjusted to compensate for errors based on correlation values from a second Golay correlator. A digital baseband signal to be adjusted is selected on a time-sharing basis. The adjusted digital baseband signal from the first RF front-end and the adjusted set of digital baseband signals from the set of respective additional RF front-ends are combined.

Claims

1. A method for receiving radio frequency (RF) signals, comprising:

adjusting a digital baseband signal from a first RF front-end to compensate for errors based on a correlation value from a first Golay correlator;

adjusting a plurality of digital baseband signals from a plurality of respective additional RF front-ends to compensate for errors based on correlation values from a second Golay correlator, wherein a digital baseband signal to be adjusted is selected on a time-sharing basis; and

combining the adjusted digital baseband signal from the first RF front-end and the adjusted plurality of digital baseband signals from the plurality of respective additional RF front-ends.

2. The method of claim 1, wherein adjusting the plurality of digital baseband signals from the plurality of respective additional RF front-ends is performed during an initialization phase.

3. The method of claim 1, wherein adjusting the digital baseband signal from the first RF front-end and the plurality of digital baseband signals from the plurality of respective additional RF front-ends comprises applying the respective correlation values to a respective interpolator and rotator.

4. The method of claim 1, further comprising:

detecting a signal preamble at the first Golay correlator; and

calculating a correlation value between the signal preamble and a predetermined preamble pattern.

5. The method of claim 1, further comprising:

selecting a first of the additional RF front-ends;

detecting a signal preamble from the selected additional RF front-end at the second Golay correlator;

calculating a correlation between the signal preamble and a predetermined preamble pattern; and

repeating said steps of selecting, detecting, and calculating for each remaining additional RF front-end.

6. The method of claim 1, further comprising adjusting the plurality of digital baseband signals from the plurality of respective additional RF front-ends based on correlation values from the first Golay correlator.

7. The method of claim 6, wherein adjusting the plurality of digital baseband signals from the plurality of respective additional RF front-ends is performed after adjustment of said signals based on the second Golay correlator is performed.

8. The method of claim 1, further comprising adjusting a beam pattern of the first RF front-end and the plurality of additional RF front-ends by adjusting a respective phase delay and amplitude of each respective front-end.

9. The method of claim 1, wherein combining the digital baseband signals from the first RF front-end and the plurality of respective additional RF front-ends comprises serially adding each signal to produce a beam-shaped total signal output.

10. A computer readable storage medium comprising a computer readable program for receiving radio frequency signals, wherein the computer readable program when executed on a computer causes the computer to perform the steps of claim 1.

11. A method for receiving radio frequency (RF) signals, comprising:

adjusting a digital baseband signal from a first RF front-end to compensate for errors based on a correlation value from a first Golay correlator, comprising;

detecting a signal preamble at the first Golay correlator;

calculating a correlation value between the signal preamble and a known preamble pattern

applying the correlation value from the first Golay correlator to a respective interpolator and rotator;

adjusting a plurality of digital baseband signals from a plurality of respective additional RF front-ends during an initialization phase to compensate for errors based on correlation values from a second Golay correlator, wherein a digital baseband signal to be adjusted is selected on a time-sharing basis, comprising;

selecting a first of the additional RF front-ends;

detecting the signal preamble from the selected additional RF front-end at the second Golay correlator;

calculating a correlation between the signal preamble and the predetermined preamble pattern; and

repeating said steps of selecting, detecting, and calculating for each remaining additional RF front-end; and

combining the adjusted digital baseband signal from the first RF front-end and the adjusted plurality of digital baseband signals from the plurality of respective additional RF front-ends.

12. A system for receiving radio frequency (RF) signals, comprising:

a plurality of RF front-ends, comprising a first RF front-end and a plurality of additional RF front-ends;

a digital baseband circuit configured to adjust a digital baseband signal from the first RF front-end to compensate for errors based on a correlation value from a first Golay correlator;

a plurality of digital combiner circuits, each configured to adjust a respective digital baseband signals from a respective additional RF front-end to compensate for errors based on correlation values from a second Golay correlator, wherein a digital baseband signal to be adjusted is selected on a time-sharing basis; and

a summer configured to combine the adjusted digital baseband signal from the first RF front-end and the adjusted plurality of digital baseband signals from the plurality of respective digital combiner circuits.

13. The system of claim 12, wherein the plurality of digital combiner circuits is configured to adjust adjusting the plurality of respective digital baseband signals during an initialization phase.

14. The system of claim 12, wherein the digital baseband circuit and the plurality of digital combiner circuits are each configured to applying the respective correlation values to a respective interpolator and rotator.

15. The system of claim 12, wherein the digital baseband circuit comprises the first Golay correlator and wherein the first Golay correlator is further configured to detect a signal preamble and to calculate a correlation value between the signal preamble and a predetermined preamble pattern.

16. The system of claim 12, further comprising a selection circuit coupled to the second Golay correlator configured to iteratively select each RF front-end from the plurality of additional RF front-ends and wherein, for each selected front-end, the second Golay correlator is configured to detect a signal preamble from the selected additional RF front-end at the second Golay correlator, and to calculate a correlation between the signal preamble and a known preamble pattern.

17. The system of claim 12, wherein the plurality of digital combiner circuits are further configured to adjust the plurality of digital baseband signals from the plurality of respective additional RF front-ends based on correlation values from the first Golay correlator.

18. The system of claim 17, wherein the plurality of digital combiner circuits are further configured to perform adjustment based on correlation values from the first Golay correlator after adjustment of said signals based on the second Golay correlator is performed.

19. The system of claim 12, further comprising a phased array control configured to adjust a beam pattern of the first RF front-end and the plurality of additional RF front-ends by adjusting a respective phase delay and amplitude of each respective front-end.

20. The system of claim 12, wherein the summer is further configured to serially adding each signal to produce a beam-shaped total signal output.