METHOD AND APPARATUS FOR REDUCING CURRENT CONSUMPTION OF MIMO SYSTEMS

• US 20090021302A1
• Filed: 11/28/2006
• Published: 01/22/2009
• Est. Priority Date: 11/28/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Paragon Communications Limited
• Inventors: Elia, Avner
• Granted Patent: US 7,868,700 B2
• Time in Patent Office: Days
• US Class Current: 330/127
• CPC Class Codes: H03F 1/02 Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 2001/045 with means for improving efficiency

Abstract

Apparatus and method for reducing the current consumption and increasing the efficiency of a MIMO system, consisting of one or more RF power amplifiers (PAs) and that is required to provide a desired total output power level. An individual output power level which is a portion of the total output power level is determined for each PA. The load, connected to the output stage of each PA, is dynamically or statically tuned to essentially match the output impedance of its output stage, such that its dynamic or static RF load line has a slope that corresponds to the impedance required to provide this portion. Whenever a smaller output power is desired in response to reduction in the input signal to MIMO system, a reduced portion is determined for each PA and the load is further tuned, such that the dynamic/static RF load line has a slope that causes each PA to essentially remain in saturation while providing the reduced portion.

Claims

1. A method for reducing the current consumption and increasing the efficiency of a MIMO system, consisting of one or more RF power amplifiers (PAs) and that is required to provide a desired total output power level, comprising:

a) Determining an individual output power level for each PA, being a portion of said total output power level;

b) dynamically or statically tuning the load, connected to the output stage of each PA, to essentially match the output impedance of its output stage, such that its dynamic or static RF load line has a slope that corresponds to the impedance required to provide said portion;

c) whenever a smaller output power is desired in response to reduction in the input signal to MIMO system, determining a reduced portion for each PA; and

d) further tuning said load, such that the dynamic/static RF load line has a slope that causes each PA to essentially remain in saturation while providing said reduced portion.

2. A method according to claim 1, wherein whenever only a single PA is activated in the MIMO system, increasing the efficiency of said MIMO system by:

a) Determining a Reduced output power level for said PA, being a portion of said total output power level;

b) dynamically or statically tuning the load, connected to the output stage of said PA, to essentially match the output impedance of its output stage, such that its dynamic or static RF load line has a slope that corresponds to the impedance required to provide said portion; and

c) allowing said PA to provide the desired total output power level by enhancing the DC power supplied to said PA, by a level that causes said dynamic or static RF load line to intersect the drain-source voltage at a value being closer to the maximal allowable swing, while essentially keeping its slope.

3. A method according to claim 1, wherein the PA operated under the following classes:

Class B;

Class AB;

Class C.

4. Apparatus for reducing the current consumption and increasing the efficiency of a MIMO system, consisting of one or more RF power amplifiers (PAs) and that is required to provide a desired total output power level, comprising:

a) matching circuitry for dynamically or statically tuning the load, connected to the output stage of each PA, to essentially match the output impedance of its output stage, such that its dynamic or static RF load line has a slope that corresponds to the impedance required to provide a portion of said total output power level, such that the dynamic or static RF load line has a slope that causes each PA to essentially remain in saturation while providing said reduced portion; and

b) power combining circuitry for combining the power output of each PA to provide the total output power at the output of said MIMO system.

5. Apparatus according to claim 4, further comprising enhancement circuitry for enhancing the DC power supplied to said PA whenever only a single PA is activated in the MIMO system by a level that causes said dynamic or static RF load line to intersect the drain-source source voltage of said PA at a value being closer to the maximal allowable swing, while essentially keeping its slope.

6. Apparatus according to claims 4 or 5, wherein the PA operated under the following classes:

Class B;

Class AB;

Class C.