# US 9,521,616 B2 · Apparatus and method for reducing power comsumption in multi antenna system

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- Number: US 9,521,616 B2
- Document ID: US9521616B2
- Status: Granted
- Kind: B2
- Application number: 14/507,194
- Filed: 2014-10-06
- Published: 2015-01-22
- Granted: 2016-12-13
- Earliest claimed: 2009-09-29
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Byung-Ki Kim; Mi-Yeon Yu
- Web page: https://patentgrep.com/patent/US9521616B2

## CPC

- H04W 52/0206: {in access points, e.g. base stations}
- H04B 7/04: using two or more spaced independent antennas
- H04W 52/0274: {by switching on or off the equipment or parts thereof}
- H04W 52/42: in systems with time, space, frequency or polarisation diversity
- H04W 88/08: Access point devices
- Y02D 30/70: in wireless communication networks
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

An apparatus and method for reducing the power consumption of a Base Station (BS) in a multi antenna system are provided. The method for reducing the power consumption of the BS includes identifying an amount of resources being in use for communication, determining whether to convert at least one Radio Frequency (RF) unit into a power saving mode considering the amount of resources, if converting at least one RF unit into the power saving mode, turning OFF a power supply of a power amplifier of at least one of at least two antenna paths constituting the at least one RF unit converted into the power saving mode, and increasing a gain of at least one antenna path turning ON a power supply such that a transmission Power Spectral Density (PSD) is not changed according to the power saving mode conversion.

## Claims

### Claim 1

A method for reducing power consumption of a base station (BS) including at least one radio frequency (RF) unit, the method comprising:
identifying a resource assigned by the BS;
determining, by comparing the resource assigned by the BS for communication with a reference value, whether to transition the at least one RF unit to a power saving mode; and
if the at least one RF unit is transitioned to the power saving mode, turning off a power input to a power amplifier of at least one of at least two antenna paths of the at least one RF unit.

### Claim 2 (depends on 1)

The method of claim 1, further comprising increasing a gain of another one of the at least two antenna paths.

### Claim 3 (depends on 1)

The method of claim 1, wherein the at least two antenna paths of the at least one RF unit are used before the transition to the power saving mode.

### Claim 4 (depends on 1)

The method of claim 1, wherein the determining of whether to transition the at least one RF unit into the power saving mode comprises:
if the resource assigned by the BS is less than the reference value, determining to transition the at least one RF unit into the power saving mode.

### Claim 5 (depends on 1)

The method of claim 1, wherein the reference value is determined depending on the number of antennas that the BS has installed.

### Claim 6 (depends on 1)

The method of claim 1, wherein, in a case in which the BS has two antennas, the reference value is set to a value of 60-80% of the maximum resources available by the BS.

### Claim 7 (depends on 1)

The method of claim 1, wherein, in a case in which the BS has two antennas and a crest factor reduction (CFR) is applied, the reference value is set to a value of 60-80% of the maximum resources available by the BS.

### Claim 8 (depends on 2)

The method of claim 2, wherein the increasing of the gain of the other one antenna path comprises, in a case in which the BS has two antennas, increasing the gain of the other antenna path to a determined amount.

### Claim 9 (depends on 1)

The method of claim 1, further comprising, in a case of turning off the power supply from the power amplifier, restricting a resource available when performing communication through the other antenna path.

### Claim 10 (depends on 1)

The method of claim 1, wherein the resource comprises any one of a number of resource blocks (RBs) and a number of subchannels.

### Claim 11

A base station (BS) apparatus for reducing power consumption in a wireless communication system, the apparatus comprising:
at least two antennas; and
a controller configured to determine, by comparing a resource assigned by the BS for communication with a reference value, whether to transition at least one radio frequency (RF) unit into a power saving mode based on the resource assigned by the BS for communication; and
the controller configured to, if the controller determines the transition into the power saving mode for the at least one RF unit, turn off a power input to a power amplifier of at least one of at least two antenna paths of the at least one RF unit transitioned into the power saving mode.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the at least one RF unit is further configured to increase a gain of another one of the at least two antenna paths.

### Claim 13 (depends on 11)

The apparatus of claim 11, wherein the at least two antenna paths of the at least one RF unit are used before the transition to the power saving mode.

### Claim 14 (depends on 11)

The apparatus of claim 11, wherein the controller comprises:
an RF scheduler configured to control the power saving mode for the transition of the at least one RF unit based on the resource assigned by the BS for communication; and
a modulator/demodulator comprising an encoder configured to modulate/demodulate a baseband signal.

### Claim 15 (depends on 14)

The apparatus of claim 14, wherein, if the resource assigned by the BS for communication is less than a reference value, the RF scheduler determines to transition the at least one RF unit into the power saving mode.

### Claim 16 (depends on 11)

The apparatus of claim 11, wherein the reference value is determined depending on the number of antennas that the BS has installed.

### Claim 17 (depends on 11)

The apparatus of claim 11, wherein, in a case in which the BS has two antennas, the reference value is set to a value of 60-80% of the maximum resources available by the BS.

### Claim 18 (depends on 11)

The apparatus of claim 11, wherein, in a case in which the BS has two antennas and a crest factor reduction (CFR) is applied, the reference value is set to a value of 60-80% of the maximum resources available by the BS.

### Claim 19 (depends on 14)

The apparatus of claim 14, wherein, in a case in which the BS has two antennas, the RF scheduler increases the gain of the other antenna path to a determined amount.

### Claim 20 (depends on 14)

The apparatus of claim 14, wherein, if the at least one RF unit is transitioned into the power saving mode, the RF scheduler restricts the resource available for communication through the other antenna path.

### Claim 21 (depends on 11)

The apparatus of claim 11, wherein the controller determines whether to transition the RF unit into the power saving mode based on the resource comprising any one of a number of resource blocks (RBs) and a number of subchannels.

### Claim 22

A method for reducing power consumption of a base station (BS) including at least one radio frequency (RF) unit in a wireless communication system, the method comprising:
identifying a resource assigned by the BS; and
if the resource assigned by the BS for communication is less than a reference value, reducing a power input to a power amplifier of at least one of at least two antenna paths of the at least one RF unit.

### Claim 23 (depends on 22)

The method of claim 22, further comprising increasing a gain of another one of the at least two antenna paths.

### Claim 24 (depends on 22)

The method of claim 22, wherein the at least two antenna paths of the at least one RF unit are used before the transition to the power saving mode.

### Claim 25 (depends on 22)

The method of claim 22, wherein reducing a power input to a power amplifier of at least one of at least two antenna paths of the at least one RF unit comprises:
comparing the radiated power of the at least one RF unit with a reference value;
if the resource assigned by the BS is less than the reference value, determining to transition the at least one RF unit into a power saving mode; and
reducing the power input to the power amplifier of the at least one of the at least two antenna paths of the at least one RF unit.

### Claim 26 (depends on 22)

The method of claim 22, wherein the reference value is determined depending on the number of antennas that the BS has installed.

### Claim 27 (depends on 22)

The method of claim 22, wherein, in a case in which the BS has two antennas, the reference value is set to a value of 60-80% of the maximum resources available by the BS.

### Claim 28 (depends on 22)

The method of claim 22, wherein, in a case in which the BS has two antennas and a crest factor reduction (CFR) is applied, the reference value is set to a value of 60-80% of the maximum resources available by the BS.

### Claim 29 (depends on 23)

The method of claim 23, wherein the increasing of the gain of the other antenna path comprises, in a case in which the BS has two antennas, increasing the gain of the other antenna path to a determined amount.

### Claim 30 (depends on 22)

The method of claim 22, further comprising, in the case of reducing the power supply from the power amplifier, restricting the resource available when performing communication through the other antenna path.

### Claim 31 (depends on 22)

The method of claim 22, wherein the resource comprises any one of a number of resource blocks (RBs) and a number of subchannels.

### Claim 32

A base station (BS) apparatus for reducing power consumption in a wireless communication system, the apparatus comprising:
at least two antennas; and
a controller configured to identify a resource assigned by the BS, and if the resource assigned by the BS for communication is less than a reference value, reduce a power input to a power amplifier of at least one of at least two antenna paths of at least one RF unit.

### Claim 33 (depends on 32)

The apparatus of claim 32, wherein the controller is further configured to increase a gain of another one of the at least two antenna paths.

### Claim 34 (depends on 32)

The apparatus of claim 32, wherein the at least two antenna paths of the at least one RF unit are used before the transition to the power saving mode.

### Claim 35 (depends on 32)

The apparatus of claim 32, wherein the controller comprises:
an RF scheduler configured to control a power saving mode for the transition of the at least one RF unit based on the resource assigned by the BS for communication; and
a modulator/demodulator (modem) comprising an encoder configured to modulate/demodulate a baseband signal.

### Claim 36 (depends on 35)

The apparatus of claim 35, wherein, if the resource assigned by the BS for communication is less than the reference value, the RF scheduler determines to transition the at least one RF unit into the power saving mode; and
reduces the power input to the power amplifier of the at least one of the at least two antenna paths of the at least one RF unit.

### Claim 37 (depends on 32)

The apparatus of claim 32, wherein the reference value is determined depending on the number of antennas that the BS has.

### Claim 38 (depends on 32)

The apparatus of claim 32, wherein, in case that the BS has two antennas, the reference value is set to a value of 60-80% of the maximum resources available by the BS.

### Claim 39 (depends on 32)

The apparatus of claim 32, wherein, in case that the BS has two antennas and a crest factor reduction (CFR) is applied, the reference value is set to a value of 60-80% of the maximum resources available by the BS.

### Claim 40 (depends on 35)

The apparatus of claim 35, wherein, in case that the BS has two antennas, the RF scheduler increases the gain of the other antenna path to a determined amount.

### Claim 41 (depends on 35)

The apparatus of claim 35, wherein, if the at least one RF unit is transitioned into the power saving mode, the RF scheduler restricts a resource available for communication such that an output limit of a power amplifier of the at least one antenna path turning on the power supply of the power amplifier is not exceeded.

### Claim 42 (depends on 32)

The apparatus of claim 32, wherein the controller determines whether to transition the RF unit into the power saving mode based on the resource comprising any one of a number of resource blocks (RBs) and a number of subchannels.