System and method for discrete gain control in hybrid MIMO/RF beamforming

• US 8,619,927 B2
• Filed: 02/07/2013
• Issued: 12/31/2013
• Est. Priority Date: 05/29/2012
• Status: Active Grant

• Current Assignee: Magnolia Broadband Incorporated
• Original Assignee: Magnolia Broadband Incorporated
• Inventors: Kludt, Kenneth, Abreu, Eduardo, Harel, Haim
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US13/762,188
• Publication Number:
  US 20130322559A1
• Time in Patent Office: 327 Days
• Field of Search: 375/260, 375/267, 375/316, 375/347, 375/345, 455/132, 455/133, 455136-139, 455/232.1, 455/234.1, 455/234.2
• US Class Current: 375/347
• CPC Class Codes: H03G 3/20 Automatic control H03G3/005 takes precedence; combined with volume compression or expansion H03G7/00
• 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 7/088 using beam selection

Abstract

A system for selectively and discretely amplifying or attenuating antennas in a hybrid multiple-input-multiple-output (MIMO) radio distribution network (RDN) receiving system is provided herein. The system includes a MIMO receiving system comprising a MIMO baseband module having N branches; an RDN connected to the MIMO receiving system, the RDN comprising at least one beamformer fed by two or more antennas, so that a total number of antennas in the system is M, wherein M is greater than N, wherein each one of the beamformers include a passive combiner configured to combine signals coming from the antennas coupled to a respective beamformer into a combined signal, wherein the at least one beamformer is further configured to selectively amplify or attenuate in discrete steps, one or more of the signals coming from the M antennas, based on qualitative metrics measured by the MIMO baseband module.

Claims

1. A system comprising:

a multiple-input-multiple-output (MIMO) receiving system comprising a MIMO baseband module having N branches; and

a radio distribution network (RDN) connected to the MIMO receiving system, the RDN comprising at least one beamformer, wherein each one of the beamformers is fed by two or more antennas, so that a total number of antennas in the system is M, wherein M is greater than N, wherein each one of the beamformers includes a passive combiner configured to combine signals coming from the antennas coupled to a respective beamformer into a combined signal,

wherein the at least one beamformer is further configured to selectively amplify or attenuate in discrete steps, one or more of the signals coming from the M antennas prior to entering the passive combiners, wherein the amplifying or the attenuating is based on one or more qualitative metrics measured by the MIMO baseband module.

2. The system according to claim 1, further comprising a gain control module having a plurality of gain controlled low noise amplifiers (LNA), each one of the LNA being associated with a different antenna.

3. The system according to claim 1, wherein the MIMO baseband module is configured to separately measure a signal level and signal to interference plus noise ratio (SINR) of each signal coming from the antennas, and wherein the amplifying or the attenuating is based on the measured signal level and SINR of each signal coming from the antennas.

4. The system according to claim 3, wherein the discrete levels include maximum gain and “

off”

.

5. The system according to claim 3, wherein the discrete levels include maximum gain, one or more intermediate gain levels, and “

off”

.

6. The system according to claim 3, further comprising a gain control module, wherein in a case that the internal noise dominates and the level of the respective signal is below a specific threshold, the gain control module applies the discrete level “

off”

to a specific signal coming from the antennas.

7. The system according to claim 3, further comprising a gain control module, wherein in a case that a measured metric of all but one of the antennas in a specific beamformer is worse than the metric for a specific antenna in the beamformer, the gain control module is configured to bypass the combiner for the specific antenna or attenuate the rest of the antennas based on a threshold.

8. The system according to claim 3, further comprising a gain control module, wherein in a case that a measured metric such as MRC metric of some of the antennas in a specific beamformer is worse than the metric for a specific antenna in the beamformer, the gain control module is configured to selectively attenuate the weak antenna based on a threshold.

9. The system according to claim 3, further comprising a gain control module, wherein in a case that a measured metric such as MRC metric of some of the antennas in a specific beamformer is worse than the metric for a specific antenna in the beamformer, the gain control module is configured to selectively disconnect the weak antenna based on a threshold.

10. The system according to claim 3, further comprising a gain control module having a plurality of cascaded units each comprising a controllable band selector, a low noise amplifier, and a step attenuator, wherein each cascaded unit controls the gain of a different antenna signal.

11. The system according to claim 1, further comprising a gain control module configured to amplify or attenuate one or more of the signals coming from the M antennas using discrete levels.

12. The system according to claim 11, wherein the discrete levels include maximum attenuation and an intermediate attenuation level.

13. The system according to claim 12, wherein the gain control module applies the discrete level maximal attenuation to a specific signal coming from the antennas, in a case that the measured SINR of the respective signal is below a specific threshold.

14. The system according to claim 11, wherein the gain control module comprises a plurality of discrete levels attenuator configured to select between a connector, a pad having a specific attenuation level, and a disconnection, wherein each discrete levels attenuator controls the attenuation of a different antenna signal.

15. The system according to claim 14, wherein the attenuation of the pad is approximately 6.6 dB.

16. A method comprising:

receiving multiple-input-multiple-output (MIMO) radio frequency (RF) signals via M antennas;

separately measuring a signal level and signal to interference plus noise ratio (SINR) of each signal coming from the antennas;

selectively amplifying or attenuating in discrete steps, one or more of the signals coming from the M antennas;

passively combining the amplified or attenuated signals into N combined signals, wherein M is greater than N; and

conveying the N combined signals to a MIMO baseband module having N branches, wherein the selectively amplifying or attenuating is carried out based on one or more specified qualitative metrics measured by the MIMO baseband module, wherein said qualitative metrics include the measured signal level and SINR of each signal coming from the antennas.

17. The method according to claim 16, wherein the discrete levels include maximum gain and “

off”

.

18. The method according to claim 16, wherein the discrete levels include maximum gain, one or more intermediate gain levels, and “

off”

.

19. The method according to claim 16, wherein in a case that the internal noise dominates and the level of the respective signal is below a specific threshold, the amplifying or the attenuating applies the discrete level “

off”

to a specific signal coming from the antennas.