U.S. patent application number 14/959299 was filed with the patent office on 2016-03-24 for attenuation systems with cooling functions and related components and methods.
The applicant listed for this patent is Corning Optical Communications Wireless Ltd.. Invention is credited to David Godali.
Application Number | 20160088765 14/959299 |
Document ID | / |
Family ID | 52582952 |
Filed Date | 2016-03-24 |
United States Patent
Application |
20160088765 |
Kind Code |
A1 |
Godali; David |
March 24, 2016 |
ATTENUATION SYSTEMS WITH COOLING FUNCTIONS AND RELATED COMPONENTS
AND METHODS
Abstract
Attenuation systems have cooling components that produce power
in response to heat generated by the attenuator. The cooling
components can be used to power cooling fans if a primary power
source of the fans fails.
Inventors: |
Godali; David; (Modi'in
lllit, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Corning Optical Communications Wireless Ltd. |
Airport City |
|
IL |
|
|
Family ID: |
52582952 |
Appl. No.: |
14/959299 |
Filed: |
December 4, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14469873 |
Aug 27, 2014 |
9231701 |
|
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14959299 |
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61871580 |
Aug 29, 2013 |
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Current U.S.
Class: |
361/695 |
Current CPC
Class: |
H04W 84/12 20130101;
H01L 35/28 20130101; H04B 10/25753 20130101; H05K 7/20136
20130101 |
International
Class: |
H05K 7/20 20060101
H05K007/20; H01L 35/28 20060101 H01L035/28 |
Claims
1. An attenuation system, comprising: an attenuator configured to
attenuate signals from a radio frequency (RF) signal source; a
thermoelectric cooling component comprising a plurality of
thermoelectric modules and configured to receive heat generated by
the attenuator and to generate electrical current in response to
the heat; and a plurality of fans configured to receive the
electric current and to cool the attenuator, wherein the
thermoelectric modules comprise a first p-type semiconductor of a
first electron density and a second n-type semiconductor of a
second electron density different than the first electron
density.
2. The attenuation system of claim 1, wherein the cooling device is
coupled to a power source, and wherein the thermoelectric cooling
component is configured to provide electric power to the cooling
device upon failure of the power source.
3. A method of cooling in a system comprising an attenuator
configured to attenuate signals, a thermoelectric cooling component
configured to receive heat generated by the attenuator, and a
cooling device configured to cool the attenuator, the method
comprising: receiving an electrical signal at the attenuation
system; attenuating the electrical signal in the attenuation
system, wherein the attenuator generates heat in response to
attenuating the electrical signal; at a plurality of thermoelectric
modules in the thermoelectric cooling component, generating
electric current in response to the heat generation; and in
response to failure of a power source coupled to the cooling
device, providing the electric current to the cooling device.
4. The method of claim 3, wherein the electrical signal comprises
an RF signal, the method further comprising providing the
attenuated signal to a distributed communication comprising a
plurality of remote units.
5. The method of claim 4, wherein the thermoelectric modules each
comprise a first p-type semiconductor of a first electron density
and a second n-type semiconductor of a second electron density
different than the first electron density.
6. The method of claim 4, wherein the cooling device comprises at
least one fan.
7. An attenuation system, comprising: an attenuator configured to
receive and attenuate signals from an electrical signal source; and
a thermoelectric cooling component comprising a plurality of
thermoelectric modules, each thermoelecric module comprising a
first semiconductor of a first electron density and a second
semiconductor of a second electron density different than the first
electron density, the thermoelectric modules being configured to
absorb heat generated by the attenuator and to generate electrical
current in response to the heat; and a plurality of fans configured
to receive electrical current from the thermoelectric cooling
component and to cool the attenuator, wherein the thermoelectric
modules comprise a first semiconductor of a first electron density
and a second semiconductor of a second electron density different
than the first electron density.
8. The attenuation system of claim 7, wherein the plurality of fans
is coupled to a power source, and wherein the thermoelectric
cooling component is configured to provide electric power to the
cooling device when the power source fails.
9. The attenuation system of claim 8, wherein the first
semiconductor is a p-type semiconductor and the second
semiconductor is an n-type semiconductor.
10. A method of cooling in a system comprising an attenuator
configured to attenuate signals, a thermoelectric cooling component
configured to receive heat generated by the attenuator, and a
cooling device comprising at least one fan configured to cool the
attenuator, the method comprising: receiving an electrical signal
at the attenuator; attenuating the electrical signal in the
attenuator, wherein the attenuator generates heat in response to
attenuating the electrical signal; at a plurality of thermoelectric
modules in the thermoelectric cooling component, generating
electric current in response to the heat generation; receiving the
electric current at the at least one fan; and cooling the
attenuator with the at least one fan.
11. The method of claim 10, wherein the at least one fan is coupled
to a power source, and wherein providing electrical current to the
cooling device occurs in response to failure of the power
source.
12. The method of claim 11, wherein the thermoelectric modules
comprise a first p-type semiconductor of a first electron density
and a second n-type semiconductor of a second electron density
different than the first electron density.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/469,873, filed Aug. 27, 2014, which claims the benefit of
priority under 35 U.S.C. .sctn.119 of U.S. Provisional Application
Ser. No. 61/871,580, filed on Aug. 29, 2013, the contents of both
applications being relied upon and hereby incorporated by reference
herein in their entireties.
BACKGROUND
[0002] 1. Field of the Disclosure
[0003] The technology of the disclosure relates to cooling systems
and related components and methods.
[0004] 2. Technical Background
[0005] Wireless communications are subject to increasing demands
for high-speed mobile data communications. "Wireless fidelity" or
"WiFi" systems and wireless local area networks (WLANs) are now
deployed in many different types of areas to provide wireless
services. Distributed antenna systems also provide a variety of
wireless services by communicating with wireless devices called
"client devices" which must reside within the wireless range or
"cell coverage area." Distributed antenna systems are particularly
useful inside buildings or other indoor environments where client
devices may not otherwise receive radio frequency (RF) signals.
Distributed antenna systems have RF antenna coverage areas, also
referred to as "antenna coverage areas," having a relatively short
range.
[0006] FIG. 1 is a schematic diagram of an optical fiber-based
distributed antenna system (DAS) 10. The system 10 generates
antenna coverage areas for establishing communication with wireless
client devices located within the RF range of the antenna coverage
areas. The DAS 10 includes a central unit or head-end unit (HEU)
12, remote antenna units (RAUs) 14, and an optical fiber link 16
that couples the HEU 12 to the RAU 14. The HEU 12 receives
communications over downlink electrical RF signals 18D from a
source or sources and provides the communications to the RAU 14.
The downlink communication signals are received through a downlink
input. The HEU 12 is also configured to return communications
received from the RAU 14, via uplink electrical RF signals 18U,
back to the sources. The optical fiber link 16 includes downlink
optical fibers 16D to carry signals communicated from the HEU 12 to
the RAU 14 and uplink optical fibers 16U to carry signals
communicated from the RAU 14 back to the HEU 12. An interface
couples the HEU 12 to the optical fiber link 16 by receiving
downlink signals and passing them to the RAU 14 through the link
16.
[0007] The DAS 10 has an antenna coverage area 20 that can be
substantially centered about the RAU 14. The antenna coverage area
20 of the RAU 14 forms an RF coverage area. The HEU 12 performs a
number of Radio-over Fiber (RoF) applications, such as
radio-frequency identification (RFID), WLAN communication, and
cellular phone service. Client devices 24 in the coverage area 20
can be mobile terminals such as cellular telephones, smart phones,
or tablet computers. The client device 24 includes an antenna 26
for receiving and/or sending RF signals. The HEU 12 includes an
electrical-to-optical (E/O) converter 28 to communicate downlink
electrical RF signals over the downlink optical fiber 16D to the
RAU 14, to in turn be communicated to the client device 24 in the
antenna coverage area 20 formed by the RAU 14. The E/O converter 28
converts the downlink electrical RF signals 18D to downlink optical
RF signals 22D to be communicated over the downlink optical fiber
16D. The RAU 14 includes an optical-to-electrical (O/E) converter
30 to convert received downlink optical RF signals back to
electrical signals to be communicated wirelessly through an antenna
32 to client devices 24 located in the antenna coverage area 20.
The antenna 32 receives wireless RF communication from client
devices 24 and communicates electrical RF signals representing the
wireless RF communication to an E/O converter 34 in the RAU 14. The
E/O converter 34 converts the electrical RF signals into uplink
optical RF signals 22U to be communicated over the uplink optical
fiber 16U. An O/E converter 36 in the HEU 12 converts the uplink
optical RF signals 16U into uplink electrical RF signals, which are
then communicated as uplink electrical RF signals 18U back to a
network. The RAU 14 can include a controller 40 to facilitate one
or more operations of the RAU.
[0008] DASs and other wireless systems are usually fed by a base
station, a repeater, or other RF source that provides output power
in a specified range. Since DAS equipment is usually designed to
operate with lower input power than that of the source, the signal
is attenuated between the DAS and the source. Since attenuators may
need to dissipate high power, they are often cooled by fans.
Failures of such fans can result in damage caused by electronic
components.
SUMMARY
[0009] One embodiment is addressed to a communication system
comprising a signal source, a system communicatively coupled to the
signal source in order to receive signals from the source, the
system including remote units configured to wirelessly transmit RF
signals into a respective coverage area and to receive wireless RF
signals from the coverage area; and an attenuation system
interposed between the signal source and the system to attenuate
signals from the source. The attenuation system comprises an
attenuator configured to attenuate signals, a thermoelectric
cooling component configured to absorb heat generated by the
attenuator and to generate electrical current in response to the
heat, and a cooling device in electrical communication with the
thermoelectric cooling component and arranged to cool the
attenuator when powered by the thermoelectric cooling
component.
[0010] A further embodiment is addressed to a method of operating a
communication system having an attenuation system comprising an
attenuator configured to attenuate signals, a thermoelectric
cooling component configured to absorb heat generated by the
attenuator, and a cooling device in electrical communication with
the thermoelectric cooling component and arranged to cool the
attenuator. The method comprises providing a signal to the
attenuation system, attenuating the signal in the attenuation
system so that the attenuator generates heat in response to
attenuating the signal, at the thermoelectric cooling component,
generating an electrical current in response to the heat
generation, providing the electrical current to the cooling device,
and from a plurality of remote units, wirelessly transmitting
signals into respective coverage areas. The cooling device may be
coupled to a power source, and electrical current form the
thermoelectric cooling component can be provided to the cooling
device in the event of the cessation of power or a reduction of
power supplied by the power source.
[0011] Additional features and advantages will be set forth in the
detailed description which follows. The foregoing general
description and the following detailed description are merely
exemplary. The accompanying drawings are included to provide a
further understanding, and are incorporated in and constitute a
part of this specification. The drawings illustrate one or more
embodiment(s), and together with the description serve to explain
principles and operation of the various embodiments.
BRIEF DESCRIPTION OF THE FIGURES
[0012] FIG. 1 is a schematic diagram of a distributed communication
system.
[0013] FIG. 2 is a schematic representation of a system receiving
an attenuated signal from a source by way of an attenuation system
according to a first embodiment.
[0014] FIG. 3 is a partial schematic diagram of an attenuator and a
cooling component of the attenuation system of FIG. 2.
[0015] FIG. 4 is a plot of output power versus hot side temperature
at different cold side temperatures.
DETAILED DESCRIPTION
[0016] According to one aspect of the present embodiments, a
mechanism for ensuring operation of cooling fans during power
breaks serves to avoid overheating of an attenuator and possible
damage to the attenuator and/or other electronic components. In one
embodiment, the mechanism uses modules that produce electrical
power in response to heat flow across the module.
[0017] FIG. 2 is a schematic representation of a system 55 having a
signal source 60 that provides signals to a system 80, where the
signals are attenuated in an attenuation system 100. The system 55
may be, for example, a communication system for the distribution of
RF signals. The system 80 can be any system that processes,
retransmits, or otherwise utilizes the signals from the source 60.
In one exemplary embodiment, the system 80 corresponds to a
distributed communication system, such as the DAS 10 illustrated in
FIG. 1. The source 60 can be, for example, a base transceiver
station (BTS), a small cell, a repeater, or similar source which
may be provided by a second party such as a cellular service
provider. The source 60 can be co-located with or located remotely
from the DAS 10.
[0018] The attenuation system 100 is designed to continue to
operate during power breaks. The system 100 includes an attenuator
70 that attenuates the signal(s) from the source 60 before
forwarding it to the system 80. Because attenuators generate heat
during operation, a cooling component 90, and a cooling device 95
such as a fan, or a group of fans, are provided with the attenuator
70 to cool the attenuator. The cooling device 95 can be powered
locally, for example, by a power source 97. The exemplary
embodiment illustrates one mode of operation of the system 55,
where a signal direction is from the source 60, through the
attenuation system 100, to the system 80. This signal would be
considered a downlink signal if, for example, the signal input to
the source 60 were from a network, and the system 80 were a
distributed communication system as shown in FIG. 1. The principles
of the invention also apply, however, to signal flow in the uplink
direction.
[0019] The power source 97 is expected to power the fan 95 during
normal operation of the system 55, and could be connected to a
building infrastructure's system for electrical power. If for some
reason the power source 97 fails (e.g., by a reduction and/or
cessation of supplied power) temporarily or for long periods, the
cooling component 90 is activated to power the fan 95, or
alternative fan(s) associated with the cooling component 90, to
continue cooling the attenuator 70. This function allows the system
80 to continue operating without the risk of the attenuator 70
overheating.
[0020] The cooling component 90 can include one or more elements,
or modules, that produce electrical power in response to heat flow
across the module. The electrical power is used to power the
cooling device 95 during power breaks. FIG. 3 is an isolated
section view of the attenuator 70 and the cooling component 90. The
attenuator 70 has a first, source port 104 that can be, for
example, configured to receive signals from an RF source such as a
base station. A second port 108 is configured to provide attenuated
signals from the source 60 to a system, such as the system 80.
[0021] The attenuator 70 includes a first, hot side heat sink 112
on the side that is in thermal communication with the cooling
component 90. The cooling component 90 includes a thermoelectric
component 120 in thermal contact with and arranged to receive
thermal energy from the heat sink 112. During operation of the
system 55, heat flow from the attenuator 70 crosses the
thermoelectric component 120 and is dissipated from a second,
ventilated cold side heat sink 130 in thermal communication with
the thermoelectric component.
[0022] The thermoelectric component 120 is configured to produce
electrical power in response to heat flow across the component 120.
The ability of heat flux between two different types of material to
generate electricity is known as the Peltier effect, or more
generally as the thermoelectric effect. The exemplary
thermoelectric component 120 includes a plurality of Peltier
modules (PM) 140. A Peltier cooler module is a solid-state active
in which the transfer of heat from a hot side (at the heat sink 112
in FIG. 3) to a cool side, (the second, cold side heat sink 130 in
FIG. 3) results in the generation of electrical energy. As the hot
side is heated to a temperature greater than the cool side, a
voltage difference builds between the two sides due to the Seebeck
Effect. In a Peltier module, semiconductors of different electron
densities, such as p-type and n-type, are placed electrically in
series and thermally in parallel. A thermal gradient across the
parallel connection of p-type and n-type materials results in a
current along the serial electrical connection. A larger number and
efficacy of p-n pairs provides a greater ability to generate
electrical current.
[0023] The series electrical connection of thermoelectric modules
140 can be electrically connected to the cooling device 95 such
that when the primary power source for the cooling device 95 fails,
electrical current generated by the cooling component 90 continues
to power the cooling device 95, or, another cooling device coupled
to the cooling component.
[0024] In one application, attenuation system 100 is designed to
operate in conjunction with a distributed communication system,
corresponding to the DAS 10, and a BTS. DASs are typically fed by a
base station or other RF source that provides output power in the
range of 4-20 Watts. The head end equipment for the DAS 10 may be
designed to operate with lower input power, such as in the range of
0.1-0.5 W. The attenuation system 100 is therefore configured to
attenuate signals from the BTS so that they are of suitable power
for use by the DAS. During operation, the attenuator 70 will absorb
high power (up to 20 W in some applications) and the cooling device
95, usually including multiple fans, is used to cool the attenuator
70. If local building infrastructure power to the cooling device 95
fails, the high power absorption by the attenuator 70 generates the
heat needed to operate the thermoelectric component 120 to in turn
power the cooling device 95.
[0025] In another example, the cooling device 95 includes four fans
to cool the cold side ventilated heat sink 130 at or below a
temperature of 60.degree. C. The power dissipated by the attenuator
70 is 10 W, and the heat dissipation properties of the system are
designed such that the first, hot side attenuator heat sink 112 is
90.degree. C., or 30.degree. C. higher than the temperature of the
second, cold side ventilated heat sink 130.
[0026] FIG. 4 is a plot of output power versus hot side temperature
at different cold side temperatures. Still referring to FIG. 3 and
also to the plot in FIG. 4, under certain conditions one exemplary
Peltier module produces an electric power of 1 W. If four fans are
used to cool the heat sink and keeping it at a maximum temperature
of 50.degree. C. Each fan may require 2.5 W of power, so that four
fans require about 10 W. Since, under the certain conditions, each
Peltier module generates about 1 W, at least ten Peltier modules
would be used in the cooling component 120. The power from the
Peltier modules may need to be combined and processed through a
power converter (not shown) to output a desired voltage and current
to operate the fans. Thus, additional Peltier modules may be
included to account for losses in power conversion.
[0027] The distributed communications systems disclosed in this
specification are configured to provide digital data services.
Examples of digital data services provided with digital data
signals include, but are not limited to, Ethernet, WLAN, WiMax,
WiFi, Digital Subscriber Line (DSL), and LTE, etc. Ethernet
standards could be supported, including but not limited to 100
Megabits per second (Mbs) (i.e., fast Ethernet) or Gigabit (Gb)
Ethernet, or ten Gigabit (10G) Ethernet. Examples of RF
communication services provided with RF communication signals
include, but are not limited to, US FCC and Industry Canada
frequencies (824-849 MHz on uplink and 869-894 MHz on downlink), US
FCC and Industry Canada frequencies (1850-1915 MHz on uplink and
1930-1995 MHz on downlink), US FCC and Industry Canada frequencies
(1710-1755 MHz on uplink and 2110-2155 MHz on downlink), US FCC
frequencies (698-716 MHz and 776-787 MHz on uplink and 728-746 MHz
on downlink), EU R & TTE frequencies (880-915 MHz on uplink and
925-960 MHz on downlink), EU R & TTE frequencies (1710-1785 MHz
on uplink and 1805-1880 MHz on downlink), EU R & TTE
frequencies (1920-1980 MHz on uplink and 2110-2170 MHz on
downlink), US FCC frequencies (806-824 MHz on uplink and 851-869
MHz on downlink), US FCC frequencies (896-901 MHz on uplink and
929-941 MHz on downlink), US FCC frequencies (793-805 MHz on uplink
and 763-775 MHz on downlink), and US FCC frequencies (2495-2690 MHz
on uplink and downlink), and medical telemetry frequencies.
[0028] The embodiments disclosed herein include various steps that
may be performed by hardware components or embodied in
machine-executable instructions, which may be used to cause a
general-purpose or special-purpose processor programmed with the
instructions to perform the steps. Alternatively, the steps may be
performed by a combination of hardware and software.
[0029] The operational steps described in any of the embodiments
herein are described to provide examples and discussion, and may be
performed in different sequences other than the illustrated
sequences. Operations described in a single step may actually be
performed in a number of different steps, and one or more
operational steps may be combined. Data, instructions, commands,
information, bits, symbols, and chips that may be referenced
throughout the above description may be represented by voltages,
currents, electromagnetic waves, magnetic fields or particles,
optical fields or particles, or any combination thereof.
[0030] The terms "fiber optic cables" and/or "optical fibers"
include all types of single mode and multi-mode light waveguides,
including one or more optical fibers that may be upcoated, colored,
buffered, ribbonized and/or have other organizing or protective
structure in a cable such as one or more tubes, strength members,
jackets, or the like.
[0031] The antenna arrangements disclosed herein may include any
type of antenna desired, including but not limited to dipole,
monopole, bowtie, inverted F, wireless cards, and slot antennas.
The distributed antenna systems disclosed herein could include any
type or number of communication mediums, including but not limited
to electrical conductors, optical fiber and optical cable, and air
(i.e., wireless transmission).
[0032] A BTS may be any station or source that provides an input
signal to a wireless system and that can receive a return signal
from the wireless system. In a typical cellular system, for
example, a plurality of BTSs are deployed at a plurality of remote
locations to provide wireless telephone coverage. Each BTS serves a
corresponding cell and when a mobile station enters the cell, the
BTS communicates with the mobile station. Each BTS can include at
least one radio transceiver for enabling communication with one or
more subscriber units operating within the associated cell.
[0033] Various modifications and variations can be made without
departing from the scope of the invention. Since modifications
combinations, sub-combinations and variations of the disclosed
embodiments incorporating the spirit and substance of the invention
may occur to persons skilled in the art, the invention should be
construed to include everything within the scope of the appended
claims and their equivalents.
* * * * *