Implementing blind tuning in hybrid MIMO RF beamforming systems

• US 9,065,517 B2
• Filed: 02/03/2014
• Issued: 06/23/2015
• Est. Priority Date: 05/29/2012
• Status: Active Grant

• Current Assignee: Magnolia Broadband Incorporated
• Original Assignee: Magnolia Broadband Incorporated
• Inventors: Harel, Haim, Abreu, Eduardo, Kludt, Kenneth
• Primary Examiner(s): Washburn, Daniel
• Assistant Examiner(s): HAILEGIORGIS, FITWI Y
• Application Number:
  US14/171,736
• Publication Number:
  US 20140219404A1
• Time in Patent Office: 505 Days
• Field of Search: 375/227, 375/316, 375/267, 455/562.1, 455/77, 370/329
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0413 MIMO systems
• 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: H04B 7/0874 using subgroups of receive antennas

Abstract

A system and a method for applying a blind tuning process to M antennas coupled via N beamformers to a multiple input multiple output (MIMO) receiving system having N channels, wherein M>N, are provided herein. The method includes the following steps: Periodically measuring channel fading rate at a baseband level to determine the number of antennas L out of K antennas connected to each one of the beamformers, to be combined at each one of the N beamformers; assigning the antennas to the subset L according to some criteria such as best quality indicator; repeatedly applying a tuning process to L antennas in each one of the N beamformers.

Claims

1. A method comprising:

receiving multiple input multiple output (MIMO) radio frequency (RF) signals through M antennas coupled via N beamformers to a MIMO receiving system having N channels, wherein M>

N;

measuring channel fading rate at a baseband level;

grading each one of K antennas, based on their total data throughput coming from various data streams, wherein the total data throughput is represented by a total data throughput indicator (TDTI);

determining a number of antennas L to be combined out of the K antennas of each one of the N beamformers, based on the measured fading rate, wherein the selecting of said specific subset L is based on the total data throughput grades of the K antennas; and

repeatedly applying a tuning process to L antennas at each of the N beamformers, wherein the tuning process comprises adjusting a phase of each of said L antennas to maximize a TDTI.

2. The method according to claim 1, further comprising selecting a specific subset L of the K antennas on each one of the N beamformers, based on quality indicators.

3. The method according to claim 2, wherein the quality indicator is respective contribution to total data rate.

4. The method according to claim 1, wherein the channel fading rate is represented by measuring a mobility monitoring indicator (MMI).

5. The method according to claim 1, wherein the TDTI is derivable via a lookup table based on a channel quality indicator (CQI) criterion and measured signal to noise plus interference ratio (SINR).

6. The method according to claim 1, wherein the grading of each one of the K antennas is carried out by a process comprising:

isolating a given antenna and registering the reported signal to noise plus interference ratio (SINR) of each layer;

converting each SINR to channel quality indicator (CQI) and then to Data Rate via said lookup table; and

summing the Data Rates to provide total data throughput indicator (TDTI) grading, while said process is carried out with K or less antennas at the other beamformers.

7. The method according to claim 6, further comprising a step of updating the SINR conversion in the lookup table in a case a new CQI report arrives.

8. The method according to claim 1, wherein said tuning process includes at least one round of coarse tuning process.

9. The method according to claim 1, wherein said tuning process includes a fine tuning process.

10. A method comprising:

receiving multiple input multiple output (MIMO) radio frequency (RF) signals through M antennas coupled via N beamformers to a MIMO receiving system having N channels, wherein M>

N;

measuring channel fading rate at a baseband level;

determining a number of antennas L to be combined out of K antennas of each one of the N beamformers, based on the measured fading rate; and

repeatedly applying a tuning process to L antennas at each of the N beamformers, wherein said tuning process includes at least one round of coarse tuning process, said coarse tuning process comprising;

selecting best graded antenna as an anchor;

combining the anchor with the second best graded antenna and measure Total Data Throughput Indicator (TDTI);

flipping the phase of the second best antenna by approximately 180°

, and measuring the TDTI;

choosing the better TDTI as preferred coarse phase;

combining the next best graded antenna with the previously combined antennas and measure the TDTI;

flipping the phase of the next best graded antenna and measure TDTI, and selecting the better TDTI as preferred coarse phase for the next best graded antenna;

repeating the adding of antennas to the combiner per their grading until all L antennas are added.

11. A system comprising

M antennas;

N beamformers connected to the M antennas;

a multiple input multiple output (MIMO) receiving system having N channels, connected to the N beamformers, wherein M>

N; and

an antenna subset selection and tuning module configured to;

measure channel fading rate at a baseband level;

grade each one of the K antennas, based on their total data throughput coming from various data streams, wherein the total data throughput is represented by a total data throughput indicator (TDTI);

determine a number of antennas L≦

K to be combined at each one of the N beamformers, wherein K is a number of antennas connected to each one of the beamformers, based on the measured fading rate, wherein the selecting of said specific subset L is based on the total data throughput grades of the K antennas; and

repeatedly apply a tuning process to L antennas at each of the N beamformers, wherein the tuning process comprises adjusting a phase of each of said L antennas to maximize a TDTI.

12. The system according to claim 11, wherein the antenna subset selection and tuning module is further configured to select a specific subset L of the K antennas on each one of the N beamformers, based on quality indicators.

13. The system according to claim 12, wherein the quality indicator is respective contribution to total data rate.

14. The system according to claim 11, wherein the channel fading rate is represented by measuring a mobility monitoring indicator (MMI).

15. The system according to claim 11, wherein the TDTI is derivable via a lookup table based on a channel quality indicator (CQI) criterion and measured signal to noise plus interference ratio (SINR).

16. The system according to claim 11, wherein the grading of each one of the K antennas is carried out by a process comprising:

isolating a given antenna and registering the reported signal to noise plus interference ratio (SINR) of each layer;

converting each SINR to CQI and then to Data Rate via said lookup table; and

summing the Data Rates to provide total data throughput indicator (TDTI) grading, while said process is carried out with K or less antennas at the other beamformers.

17. The system according to claim 16, wherein the antennas subset selection and tuning module is further configured to update the SINR conversion in the lookup table in a case a new CQI report arrives.

18. The system according to claim 11, wherein said tuning process includes at least one round of coarse tuning process.

19. The system according to claim 11, wherein said coarse tuning process comprises:

selecting best graded antenna as an anchor;

combining the anchor with the second best graded antenna and measure Total Data Throughput Indicator (TDTI);

flipping the phase of the second best antenna by approximately 180°

, and measuring the TDTI;

choosing the better TDTI as preferred coarse phase;

combining the next best graded antenna with the previously combined antennas and measure the TDTI;

flipping the phase of the next best graded antenna and measure TDTI, and selecting the better TDTI as preferred coarse phase for the next best graded antenna;

repeating the adding of antennas to the combiner per their grading until all L antennas are added.