USING 3G/4G BASEBAND SIGNALS FOR TUNING BEAMFORMERS IN HYBRID MIMO RDN SYSTEMS

• US 20130322574A1
• Filed: 05/07/2013
• Published: 12/05/2013
• Est. Priority Date: 05/29/2012
• Status: Active Grant

• Current Assignee: Magnolia Broadband Incorporated
• Original Assignee: Magnolia Broadband Incorporated
• Inventors: CHEN, Phil F., HAREL, Haim, WANG, Sherwin J., KLUDT, Kenneth
• Granted Patent: US 8,971,452 B2
• Time in Patent Office: Days
• US Class Current: 375/340
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0845 per branch equalization, e.g. by an FIR-filter or RAKE receiver per antenna branch rake receivers as such H04B1/7115
• 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 hybrid MIMO RDN 3G/4G receiving system which include M antennas for N MIMO branches, wherein M>N is provided herein. Each branch has a beamformer so that each of the beamformers includes at least one combiner configured to combine signals coming from the antennas coupled to a respective beamformer into a combined signal. The system further includes a control module configured to tune at least one beamformer based on metrics derived by the baseband module. More specifically, the tuning of the beamformers is carried out, at least partially, using 3G/4G metrics that are generated but not usually reported in 3G/4G air protocols, wherein these metrics are extracted by the control module.

Claims

1. A system comprising:

a multiple-input-multiple-output (MIMO) receiving system comprising a MIMO baseband module having N branches, each one of the N channels passing through a spatial separator and a fast Fourier transform (FFT) module;

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 at least one of the beamformers include at least one combiner configured to combine signals coming from the antennas coupled to a respective beamformer into a combined signal; and

a control module configured to tune the at least one beamformer based on metrics derived by the baseband module, wherein the metrics include a phase for at least some of the N channels,

wherein the phases are derived from outputs of the spatial separators and fast Fourier transform (FFT) modules.

2. The system according to claim 1, wherein the MIMO receiving system is configured for operation in accordance with the long term evolution (LTE) air protocol.

3. The system according to claim 1, wherein the baseband module is further configured to derive a reference signal received power (RSRP) and/or an reference signal received quality (RSRQ) of each channel N by rerouting unreported specific RSRP and/or RSRQ of each of the N MIMO inputs, from points in the baseband module in which the RSRP and/or RSRQ are calculated, to the control module.

4. A system comprising:

a multiple-input-multiple-output (MIMO) receiving system comprising a MIMO baseband module having N branches and a plurality of high speed packet access (HSPA)/code division multiple access(CDMA) receivers;

a radio distribution network (RDN) connected to the MIMO receiving system, the RDN comprising at least one beamformer, wherein at least 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 at least one of the beamformers include at least one combiner configured to combine signals coming from the antennas coupled to a respective beamformer into a combined signal; and

a control module configured to tune the at least one beamformer based on metrics derived by the baseband module,

wherein the metrics include a phase for at least one of the N channels, wherein the phases are derived from HSPA/CDMA receivers that process at least one of the MIMO inputs.

5. The system according to claim 4, wherein at least one of the receivers processors comprises several portions, at least one for a different finger coming from a specific MIMO input so that the derived phase is a vector summation of signals coming from at least one of said portions.

6. The system according to claim 5, wherein the vector summation comprises a first process of finger vector summation coming from a single MIMO receiver input i out of N, followed by another process wherein all N inputs are vectorlly combined.

7. The system according to claim 4, wherein the baseband module is further configured to derive the common pilot channel (CPICH) of at least one channel N by rerouting unreported specific CPICH of at least one of the N MIMO inputs, from points in the baseband module in which the CPICH are calculated, to the control module.

8. A method comprising:

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

beamforming the received RF MIMO transmission via a radio distribution network (RDN), of beamformers, wherein at least one of the beamformers include at least one combiner configured to combine signals coming from the antennas coupled to a respective beamformer into a N combined signals, wherein M is greater than N;

conveying the N combined signals to a multiple-input-multiple-output (MIMO) receiving system comprising a MIMO baseband module having N branches and a spatial separator and a fast Fourier transform (FFT) module for at least one of the channels;

deriving baseband metrics including a phase for at least one of the N channels, wherein the phases are derived from outputs of the spatial separator and the FFT modules; and

tuning the at least one beamformer based on metrics derived by the baseband module.

9. The method according to claim 8, wherein the MIMO receiving system is configured for operation in accordance with the long term evolution (LTE) air protocol.

10. The method according to claim 8, wherein the baseband module is further configured to derive a reference signal received power RSRP and/or a reference signal received quality (RSRQ) of at least channel N by rerouting unreported specific RSRP and/or RSRQ of at least one of the N MIMO inputs, from points in the baseband module in which the RSRP and/or RSRQ are calculated, to the control module.

11. A method comprising:

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

beamforming the received RF MIMO transmission via a radio distribution network (RDN), of beamformers, wherein at least one of the beamformers include at least one combiner configured to combine signals coming from the antennas coupled to a respective beamformer into a N combined signals, wherein M is greater than N;

conveying the N combined signals to a multiple-input-multiple-output (MIMO) receiving system comprising a MIMO baseband module having N branches and a plurality of high speed packet access (HSPA)/code division multiple access (CDMA) receivers;

deriving baseband metrics including a phase for at least one of the N channels, wherein the phases are derived from HSPA/CDMA receivers that process at least one of the MIMO inputs; and

tuning the at least one beamformer based on metrics derived by the baseband module.

12. The method according to claim 11, wherein at least one of the receiver processors comprises several portions, at least one for a different finger coming from a specific MIMO input so that the derived phase is a vector summation of signals coming from at least one of said portions.

13. The method according to claim 12, wherein the vector summation comprises a first process of finger vector summation coming from a single MIMO receiver input i out of N, followed by another process wherein all N inputs are vectorlly combined.

14. The method according to claim 11, wherein the baseband module is further configured to derive the common pilot channel (CPICH) of at least one channel N by rerouting unreported specific CPICH of each one of the N MIMO inputs, from points in the baseband module in which the CPICH are calculated, to the control module.