U.S. patent application number 12/892424 was filed with the patent office on 2011-11-03 for providing digital data services in optical fiber-based distributed radio frequency (rf) communications systems, and related components and methods.
Invention is credited to William P. Cune, Michael Sauer, Wolfgang Gottfried Tobias Schweiker.
Application Number | 20110268446 12/892424 |
Document ID | / |
Family ID | 44858332 |
Filed Date | 2011-11-03 |
United States Patent
Application |
20110268446 |
Kind Code |
A1 |
Cune; William P. ; et
al. |
November 3, 2011 |
PROVIDING DIGITAL DATA SERVICES IN OPTICAL FIBER-BASED DISTRIBUTED
RADIO FREQUENCY (RF) COMMUNICATIONS SYSTEMS, AND RELATED COMPONENTS
AND METHODS
Abstract
Optical fiber-based distributed communications systems that
provide and support both RF communication services and digital data
services are disclosed herein. The RF communication services and
digital data services can be distributed over optical fiber to
client devices, such as remote antenna units for example. In
certain embodiments, digital data services can be distributed over
optical fiber separate from optical fiber distributing RF
communication services. In other embodiments, digital data services
can be distributed over common optical fiber with RF communication
services. For example, digital data services can be distributed
over common optical fiber with RF communication services at
different wavelengths through wavelength-division multiplexing
(WDM) and/or at different frequencies through frequency-division
multiplexing (FDM). Power distributed in the optical fiber-based
distributed communications system to provide power to remote
antenna units can also be accessed to provide power to digital data
service components.
Inventors: |
Cune; William P.;
(Charlotte, NC) ; Sauer; Michael; (Corning,
NY) ; Schweiker; Wolfgang Gottfried Tobias; (Weyarn,
DE) |
Family ID: |
44858332 |
Appl. No.: |
12/892424 |
Filed: |
September 28, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61330386 |
May 2, 2010 |
|
|
|
61330385 |
May 2, 2010 |
|
|
|
61330383 |
May 2, 2010 |
|
|
|
Current U.S.
Class: |
398/79 ;
398/115 |
Current CPC
Class: |
H04B 10/25753 20130101;
H04Q 11/0067 20130101; H04J 14/0282 20130101; H04J 14/0298
20130101; H04B 10/25752 20130101; H04J 14/02 20130101; H04J 1/08
20130101; H04Q 2011/0016 20130101 |
Class at
Publication: |
398/79 ;
398/115 |
International
Class: |
H04J 14/02 20060101
H04J014/02; H04B 10/00 20060101 H04B010/00 |
Claims
1. A distributed antenna system for distributing radio frequency
(RF) communications and digital data services (DDS) to at least one
remote antenna unit (RAU), comprising: a head-end unit (HEU)
configured to: receive at least one downlink electrical RF
communications signal; convert the at least one downlink electrical
RF communications signal into at least one downlink optical RF
communications signal to be communicated over at least one
communications downlink to the at least one RAU; receive at least
one uplink optical RF communications signal over at least one
communications uplink from the at least one RAU; and convert the at
least one uplink optical RF communications signal into at least one
uplink electrical RF communications signal; and a DDS controller
configured to: receive at least one downlink optical digital signal
containing at least one DDS; and provide the at least one downlink
optical digital signal over at least one second communications
downlink to the at least one RAU.
2. The distributed antenna system of claim 1, wherein the DDS
controller is further configured to: receive at least one uplink
optical digital signal over at least one second communications
uplink from the at least one RAU; and convert the at least one
uplink optical digital signal to at least one uplink electrical
digital signal.
3. The distributed antenna system of claim 2, wherein the DDS
controller is further configured to: receive at least one second
uplink optical digital signal over the at least one second
communications uplink from at least one media controller (MC); and
convert the at least one second uplink optical digital signal to
the at least one second uplink electrical digital signal.
4. The distributed antenna system of claim 1, wherein the at least
one DDS is comprised from the group consisting of Ethernet,
Wireless Local Area Network (WLAN), Worldwide Interoperability for
Microwave Access (WiMax), Digital Subscriber Line (DSL), and Long
Term Evolution (LTE).
5. The distributed antenna system of claim 1, wherein the DDS
controller is comprised of a media converter.
6. The distributed antenna system of claim 1, wherein the at least
one communications downlink and the at least one communications
uplink include optical fiber.
7. The distributed antenna system of claim 1, further comprising an
interconnect unit (ICU) configured to: receive the at least one
downlink optical RF communications signal; receive the at least one
downlink optical digital signal; provide the at least one downlink
optical RF communications signal over the at least one
communications downlink to the at least one RAU; and provide the at
least one downlink optical digital signal over the at least one
second communications downlink to the at least one RAU.
8. The distributed antenna system of claim 2, further comprising an
interconnect unit (ICU) configured to: receive the at least one
uplink optical RF communications signal from the at least one RAU
over the at least one communications uplink; provide the at least
one uplink optical RF communications signal to the HEU; receive the
at least one uplink optical digital signal from the at least one
RAU over the at least one second communications uplink; and provide
the at least one uplink optical digital signal to the DDS
controller.
9. The distributed antenna system of claim 8, wherein the ICU is
further configured to: provide the at least one uplink optical RF
communications signal to the HEU; and provide the at least one
uplink optical digital signal to the DDS controller.
10. The distributed antenna system of claim 1, further comprising
at least one wave-division multiplexer (WDM) configured to
wave-division multiplex the at least one downlink optical RF
communications signal and the at least one downlink optical digital
signal at different wavelengths over at least one optical fiber
communications downlink.
11. The distributed antenna system of claim 10, further comprising
at least one wave-division de-multiplexer (WDD) associated with the
at least one RAU and configured to separate the at least one
downlink optical RF communications signal from the at least one
downlink optical digital signal received over the at least one
communications downlink.
12. The distributed antenna system of claim 2, further comprising
at least one wave-division de-multiplexer (WDM) associated with the
at least one RAU and configured to wave-division multiplex the at
least one uplink optical RF communications signal and the at least
one uplink optical digital signal at different wavelengths over the
at least one communications uplink.
13. The distributed antenna system of claim 12, further comprising
at least one wave-division de-multiplexer (WDD) configured to
separate the at least one uplink optical RF communications signal
from the at least one uplink optical digital signal received over
the at least one communications uplink.
14. The distributed antenna system of claim 10, further comprising
at least one frequency-division multiplexer (FDM) configured to
frequency-division multiplex the at least one downlink electrical
RF communications signal and at least one downlink electrical
digital signal at different frequencies over the at least one
communications downlink.
15. The distributed antenna system of claim 14, further comprising
at least one frequency-division de-multiplexer (FDD) associated
with the at least one RAU and configured to separate the at least
one downlink electrical RF communications signal from the at least
one downlink electrical digital signal from the at least one
communications downlink.
16. The distributed antenna system of claim 12, further comprising
at least one frequency-division multiplexer (FDM) associated with
the at least one RAU and configured to frequency-division multiplex
the at least one uplink electrical RF communications signal and the
at least one uplink electrical digital signal at different
frequencies from the at least one communications uplink.
17. The distributed antenna system of claim 16, further comprising
at least one frequency-division de-multiplexer (FDD) configured to
separate the at least one uplink electrical RF communications
signal from the at least one uplink electrical digital signal from
the at least one communications uplink.
18. The distributed antenna system of claim 1, further comprising
at least one frequency-division multiplexer (FDM) configured to
frequency-division multiplex the at least one downlink electrical
RF communications signal and the at least one downlink electrical
digital signal at different frequencies over the at least one
communications downlink.
19. The distributed antenna system of claim 18, further comprising
at least one frequency-division de-multiplexer (FDD) associated
with the at least one RAU and configured to separate the at least
one downlink optical RF communications signal from the at least one
downlink optical digital signal received over the at least one
communications downlink.
20. The distributed antenna system of claim 2, further comprising
at least one frequency-division multiplexer (FDM) associated with
the at least one RAU and configured to frequency-division multiplex
the at least one uplink electrical RF communications signal and the
at least one uplink electrical digital signal at different
frequencies from at least one communications uplink.
21. The distributed antenna system of claim 20, further comprising
at least one frequency-division de-multiplexer (FDD) configured to
separate the at least one uplink electrical RF communications
signal from the at least one uplink electrical digital signal from
the at least one communications uplink.
22. The distributed antenna system of claim 1, wherein the at least
one second communications downlink is comprised of at least one
second optical fiber communications downlink.
23. The distributed antenna system of claim 2, wherein the at least
one second communications uplink is comprised of at least one
second optical fiber communications uplink.
24. A method of distributing radio frequency (RF) communications
and digital data services (DDS) to at least one remote antenna unit
(RAU) in a distributed antenna system, comprising: receiving at a
head-end unit (HEU) at least one downlink electrical RF
communications signal; converting the at least one downlink
electrical RF communications signal into at least one downlink
optical RF communications signal to be communicated over at least
one communications downlink to the at least one RAU; receiving at
the HEU at least one uplink optical RF communications signal over
at least one communications uplink from the at least one RAU;
converting the at least one uplink optical RF communications signal
into at least one uplink electrical RF communications signal;
receiving at a digital data services (DDS) controller at least one
downlink optical digital signal containing at least one DDS; and
providing the at least one downlink optical digital signal over at
least one second communications downlink to the at least one
RAU.
25. The method of claim 24, further comprising: receiving at the
DDS controller at least one uplink optical digital signal over at
least one second communications uplink from the at least one RAU;
and providing at least one second uplink optical digital signal to
a DDS network.
26. The method of claim 24, further comprising wave-division
multiplexing the at least one downlink optical RF communications
signal and the at least one downlink optical digital signal at
different wavelengths over at least one optical fiber
communications downlink.
27. The method of claim 26, further comprising wave-division
de-multiplexing the at least one downlink optical RF communications
signal from the at least one downlink optical digital signal
received over the at least one optical fiber communications
downlink.
28. The method of claim 24, further comprising frequency-division
multiplexing the at least one downlink electrical RF communications
signal and the at least one downlink optical digital signal at
different frequencies over the at least one communications
downlink.
29. The method of claim 28, further comprising frequency-division
de-multiplexing the at least one downlink optical RF communications
signal from the at least one downlink optical digital signal
received over the at least one communications downlink.
30. A remote antenna unit for use in a distributed antenna system,
comprising: an optical-to-electrical (0-E) converter configured to
convert received downlink optical radio frequency (RF)
communications signals to downlink electrical RF communications
signals and provide the downlink electrical RF communications
signals at least one first port; an electrical-to-optical (E-O)
converter configured to convert uplink electrical RF communications
signals received from the at least one first port to uplink optical
RF communication signals; and a digital data services (DDS)
interface coupled to at least one second port and configured to:
convert downlink optical digital signals into downlink electrical
digital signals to provide to the at least one second port; and
convert uplink electrical digital signals received from the at
least one second port into uplink optical digital signals.
31. The remote antenna unit of claim 30, wherein the downlink
optical RF communications signals are received over at least one
first communications downlink connected to a head-end unit
(HEU).
32. The remote antenna unit of claim 30, wherein the downlink
optical digital signals are received over at least one second
communications downlink connected to a DDS controller.
33. The remote antenna unit of claim 30, wherein the DDS interface
further comprises a power interface configured to receive
electrical power and provide the electrical power to the at least
one second port.
34. The remote antenna unit of claim 33, wherein the at least one
second port is configured to support Power-over-Ethernet (PoE).
35. The remote antenna unit of claim 34, wherein the DDS interface
is configured to receive the electrical power from an electrical
power line provided in at least one array cable.
36. The remote antenna unit of claim 30, configured to receive the
downlink optical RF communications signals and downlink digital
optical signals from at least one array cable.
Description
RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Patent Application No. 61/330,386 filed on May 2, 2010 entitled,
"Providing Digital Data Services in Optical Fiber-based Distributed
Radio Frequency (RF) Communications Systems, and Related Components
and Methods," which is incorporated herein by reference in its
entirety.
[0002] The present application is related to U.S. Provisional
Patent Application No. 61/330,385 filed on May 2, 2010 entitled,
"Power Distribution in Optical Fiber-based Distributed
Communications Systems Providing Digital Data and Radio Frequency
(RF) Communications Services, and Related Components and Methods,"
which is incorporated herein by reference in its entirety.
[0003] The present application is also related to U.S. Provisional
Patent Application No. 61/330,383 filed on May 2, 2010 entitled,
"Optical Fiber-based Distributed Communications Systems, and
Related Components and Methods," which is incorporated herein by
reference in its entirety.
BACKGROUND
[0004] 1. Field of the Disclosure
[0005] The technology of the disclosure relates to optical
fiber-based distributed communications systems for distributing
radio frequency (RF) signals over optical fiber.
[0006] 2. Technical Background
[0007] Wireless communication is rapidly growing, with
ever-increasing demands for high-speed mobile data communication.
As an example, so-called "wireless fidelity" or "WiFi" systems and
wireless local area networks (WLANs) are being deployed in many
different types of areas (e.g., coffee shops, airports, libraries,
etc.). Distributed communications systems communicate with wireless
devices called "clients," which must reside within the wireless
range or "cell coverage area" in order to communicate with an
access point device.
[0008] One approach to deploying a distributed communications
system involves the use of radio frequency (RF) antenna coverage
areas, also referred to as "antenna coverage areas." Antenna
coverage areas can have a radius in the range from a few meters up
to twenty meters as an example. Combining a number of access point
devices creates an array of antenna coverage areas. Because the
antenna coverage areas each cover small areas, there are typically
only a few users (clients) per antenna coverage area. This allows
for minimizing the amount of RF bandwidth shared among the wireless
system users. It may be desirable to provide antenna coverage areas
in a building or other facility to provide distributed
communications system access to clients within the building or
facility. However, it may be desirable to employ optical fiber to
distribute communication signals. Benefits of optical fiber include
increased bandwidth.
[0009] One type of distributed communications system for creating
antenna coverage areas, called "Radio-over-Fiber" or "RoF,"
utilizes RF signals sent over optical fibers. Such systems can
include a head-end station optically coupled to a plurality of
remote antenna units that each provides antenna coverage areas. The
remote antenna units can each include RF transceivers coupled to an
antenna to transmit RF signals wirelessly, wherein the remote
antenna units are coupled to the head-end station via optical fiber
links. The RF transceivers in the remote antenna units are
transparent to the RF signals. The remote antenna units convert
incoming optical RF signals from an optical fiber downlink to
electrical RF signals via optical-to-electrical (O/E) converters,
which are then passed to the RF transceiver. The RF transceiver
converts the electrical RF signals to electromagnetic signals via
antennas coupled to the RF transceiver provided in the remote
antenna units. The antennas also receive electromagnetic signals
(i.e., electromagnetic radiation) from clients in the antenna
coverage area and convert them to electrical RF signals (i.e.,
electrical RF signals in wire). The remote antenna units then
convert the electrical RF signals to optical RF signals via
electrical-to-optical (E/O) converters. The optical RF signals are
then sent over an optical fiber uplink to the head-end station.
SUMMARY OF THE DETAILED DESCRIPTION
[0010] Embodiments disclosed in the detailed description include
optical fiber-based distributed communications systems that provide
and support both radio frequency (RF) communication services and
digital data services. The RF communication services and digital
data services can be distributed over optical fiber to client
devices, such as remote antenna units for example. Digital data
services can be distributed over optical fiber separate from
optical fiber distributing RF communication services.
Alternatively, digital data services can be distributed over common
optical fiber with RF communication services. For example, digital
data services can be distributed over common optical fiber with RF
communication services at different wavelengths through
wavelength-division multiplexing (WDM) and/or at different
frequencies through frequency-division multiplexing (FDM). Power
distributed in the optical fiber-based distributed communications
system to provide power to remote antenna units can also be
accessed to provide power to digital data service components.
[0011] In one embodiment, a distributed antenna system for
distributing RF communications and digital data services (DDS) to
at least one remote antenna unit (RAU) is provided. The distributed
antenna system includes a head-end unit (HEU). The HEU is
configured to receive at least one downlink electrical RF
communications signal. The HEU is also configured to convert the at
least one downlink electrical RF communications signal into at
least one downlink optical RF communications signal to be
communicated over at least one communications downlink to the at
least one RAU. The HEU is also configured to receive at least one
uplink optical RF communications signal over at least one
communications uplink from the at least one RAU. The HEU is also
configured to convert the at least one uplink optical RF
communications signal into at least one uplink electrical RF
communications signal. The distributed antenna system also includes
a DDS controller. The DDS controller is configured to receive at
least one downlink optical digital signal containing at least one
DDS, and provide the at least one downlink optical digital signal
over at least one second communications downlink to the at least
one RAU.
[0012] In another embodiment, a method of distributing RF
communications and DDS to at least one RAU in a distributed antenna
system is provided. The method includes receiving at an HEU at
least one downlink electrical RF communications signal. The method
also includes converting the at least one downlink electrical RF
communications signal into at least one downlink optical RF
communications signal to be communicated over at least one
communications downlink to the at least one RAU. The method also
includes receiving at the HEU at least one uplink optical RF
communications signal over at least one communications uplink from
the at least one RAU. The method also includes converting the at
least one uplink optical RF communications signal into at least one
uplink electrical RF communications signal. The method also
includes receiving at a DDS controller at least one downlink
optical digital signal containing at least one DDS, and providing
the at least one downlink optical digital signal over at least one
second communications downlink to the at least one RAU.
[0013] In another embodiment, an RAU for use in a distributed
antenna system is provided. The RAU includes an
optical-to-electrical (O-E) converter configured to convert
received downlink optical RF communications signals to downlink
electrical RF communications signals and provide the downlink
electrical RF communications signals at least one first port. The
RAU also includes an electrical-to-optical (E-O) converter
configured to convert uplink electrical RF communications signals
received from the at least one first port into uplink optical RF
communications signals. The RAU also includes a DDS interface
coupled to at least one second port. The DDS interface is
configured to convert downlink optical digital signals into
downlink electrical digital signals to provide to the at least one
second port, and convert uplink electrical digital signals received
from the at least one second port into uplink optical digital
signals.
[0014] Additional features and advantages will be set forth in the
detailed description which follows, and in part will be readily
apparent to those skilled in the art from that description or
recognized by practicing the embodiments as described herein,
including the detailed description that follows, the claims, as
well as the appended drawings.
[0015] It is to be understood that both the foregoing general
description and the following detailed description present
embodiments, and are intended to provide an overview or framework
for understanding the nature and character of the disclosure. The
accompanying drawings are included to provide a further
understanding, and are incorporated into and constitute a part of
this specification. The drawings illustrate various embodiments,
and together with the description serve to explain the principles
and operation of the concepts disclosed.
BRIEF DESCRIPTION OF THE FIGURES
[0016] FIG. 1 is a schematic diagram of an exemplary optical
fiber-based distributed communications system;
[0017] FIG. 2 is a more detailed schematic diagram of an exemplary
head-end unit (HEU) and a remote antenna unit (RAU) that can be
deployed in the optical fiber-based distributed communications
system of FIG. 1;
[0018] FIG. 3 is a partially schematic cut-away diagram of an
exemplary building infrastructure in which the optical fiber-based
distributed communications system in FIG. 1 can be employed;
[0019] FIG. 4 is a schematic diagram of an exemplary embodiment of
providing digital data services over downlink and uplink optical
fibers separate from optical fibers providing radio frequency (RF)
communication services to RAUs in an optical fiber-based
distributed communications system;
[0020] FIG. 5 is a diagram of an exemplary head-end media converter
(HMC) employed in the optical fiber-based distributed
communications system of FIG. 4 containing digital media converters
(DMCs) configured to convert electrical digital signals to optical
digital signals and vice versa;
[0021] FIG. 6 is a diagram of exemplary DMCs employed in the HMC of
FIG. 5;
[0022] FIG. 7 is a schematic diagram of an exemplary building
infrastructure in which digital data services and RF communication
services are provided in an optical fiber-based distributed
communications system;
[0023] FIG. 8 is a schematic diagram of an exemplary RAU that can
be employed in an optical fiber-based distributed communications
system providing exemplary digital data services and RF
communication services;
[0024] FIG. 9 is a schematic diagram of another exemplary
embodiment of providing digital data services over separate
downlink and uplink optical fibers from RF communication services
to RAUs in an optical fiber-based distributed communications
system;
[0025] FIG. 10A is a schematic diagram of an exemplary embodiment
of employing wavelength-division multiplexing (WDM) to multiplex
digital data services and RF communication services at different
wavelengths over downlink and uplink optical fibers in an optical
fiber-based distributed communications system;
[0026] FIG. 10B is a schematic diagram of an exemplary embodiment
of employing WDM to multiplex uplink and downlink communications
for each channel over a common optical fiber;
[0027] FIG. 11 is a schematic diagram of another exemplary
embodiment of employing WDM in a co-located HEU and HMC to
multiplex digital data services and RF communication services at
different wavelengths over common downlink optical fibers and
common uplink optical fibers in an optical fiber-based distributed
communications system;
[0028] FIG. 12 is a schematic diagram of another exemplary
embodiment of employing WDM in a common housing HEU and MC to
multiplex digital data services and RF communication services at
different wavelengths over a common downlink optical fiber and a
common uplink optical fiber in an optical fiber-based distributed
communications system;
[0029] FIG. 13 is a schematic diagram of another exemplary
embodiment of employing frequency-division multiplexing (FDM) to
multiplex digital data services and RF communication services at
different frequencies over downlink optical fibers and uplink
optical fibers in an optical fiber-based distributed communications
system; and
[0030] FIG. 14 is a schematic diagram of another exemplary
embodiment of employing FDM and WDM to multiplex digital data
services and RF communication services at different frequencies and
at different wavelengths over downlink optical fibers and uplink
optical fibers in an optical fiber-based distributed communications
system.
DETAILED DESCRIPTION
[0031] Reference will now be made in detail to the embodiments,
examples of which are illustrated in the accompanying drawings, in
which some, but not all embodiments are shown. Indeed, the concepts
may be embodied in many different forms and should not be construed
as limiting herein; rather, these embodiments are provided so that
this disclosure will satisfy applicable legal requirements.
Whenever possible, like reference numbers will be used to refer to
like components or parts.
[0032] Embodiments disclosed in the detailed description include
optical fiber-based distributed communications systems that provide
and support both radio frequency (RF) communication services and
digital data services. The RF communication services and digital
data services can be distributed over optical fiber to client
devices, such as remote antenna units for example. For example,
non-limiting examples of digital data services include Ethernet,
WLAN, Worldwide Interoperability for Microwave Access (WiMax),
Wireless Fidelity (WiFi), Digital Subscriber Line (DSL), and Long
Term Evolution (LTE), etc. Digital data services can be distributed
over optical fiber separate from optical fiber distributing RF
communication services. Alternatively, digital data services can be
distributed over common optical fiber with RF communication
services. For example, digital data services can be distributed
over common optical fiber with RF communication services at
different wavelengths through wavelength-division multiplexing
(WDM) and/or at different frequencies through frequency-division
multiplexing (FDM). Power distributed in the optical fiber-based
distributed communications system to provide power to remote
antenna units can also be accessed to provide power to digital data
service components.
[0033] In this regard, an exemplary optical fiber-based distributed
communications system that provides RF communication services
without providing digital data services is described with regard to
FIGS. 1-3. Various embodiments of additionally providing digital
data services in conjunction with RF communication services in
optical fiber-based distributed communications systems starts at
FIG. 4.
[0034] In this regard, FIG. 1 is a schematic diagram of an
embodiment of an optical fiber-based distributed communications
system. In this embodiment, the system is an optical fiber-based
distributed communications system 10 that is configured to create
one or more antenna coverage areas for establishing communications
with wireless client devices located in the radio frequency (RF)
range of the antenna coverage areas. The optical fiber-based
distributed communications system 10 provides RF communications
service (e.g., cellular services). In this embodiment, the optical
fiber-based distributed communications system 10 includes a
head-end unit (HEU) 12, one or more remote antenna units (RAUs) 14,
and an optical fiber 16 that optically couples the HEU 12 to the
RAU 14. The HEU 12 is configured to receive communications over
downlink electrical RF signals 18D from a source or sources, such
as a network or carrier as examples, and provide such
communications to the RAU 14. The HEU 12 is also configured to
return communications received from the RAU 14, via uplink
electrical RF signals 18U, back to the source or sources. In this
regard in this embodiment, the optical fiber 16 includes at least
one downlink optical fiber 16D to carry signals communicated from
the HEU 12 to the RAU 14 and at least one uplink optical fiber 16U
to carry signals communicated from the RAU 14 back to the HEU
12.
[0035] The optical fiber-based distributed communications system 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 21. The HEU 12 is adapted to perform or to
facilitate any one of a number of Radio-over-Fiber (RoF)
applications, such as radio frequency (RF) identification (RFID),
wireless local-area network (WLAN) communication, or cellular phone
service. Shown within the antenna coverage area 20 is a client
device 24 in the form of a mobile device as an example, which may
be a cellular telephone as an example. The client device 24 can be
any device that is capable of receiving RF communication signals.
The client device 24 includes an antenna 26 (e.g., a wireless card)
adapted to receive and/or send electromagnetic RF signals.
[0036] With continuing reference to FIG. 1, to communicate the
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 HEU 12 includes
an electrical-to-optical (E/O) converter 28. 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 22D back to
electrical RF signals to be communicated wirelessly through an
antenna 32 of the RAU 14 to client devices 24 located in the
antenna coverage area 20.
[0037] Similarly, the antenna 32 is also configured to receive
wireless RF communications from client devices 24 in the antenna
coverage area 20. In this regard, the antenna 32 receives wireless
RF communications from client devices 24 and communicates
electrical RF signals representing the wireless RF communications
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
provided in the HEU 12 converts the uplink optical RF signals 22U
into uplink electrical RF signals, which can then be communicated
as uplink electrical RF signals 18U back to a network or other
source. The HEU 12 in this embodiment is not able to distinguish
the location of the client devices 24 in this embodiment. The
client device 24 could be in the range of any antenna coverage area
20 formed by an RAU 14.
[0038] FIG. 2 is a more detailed schematic diagram of the exemplary
optical fiber-based distributed communications system of FIG. 1
that provides electrical RF service signals for a particular RF
service or application. In an exemplary embodiment, the HEU 12
includes a service unit 37 that provides electrical RF service
signals by passing (or conditioning and then passing) such signals
from one or more outside networks 38 via a network link 39. In a
particular example embodiment, this includes providing WLAN signal
distribution as specified in the Institute of Electrical and
Electronics Engineers (IEEE) 802.11 standard, i.e., in the
frequency range from 2.4 to 2.5 GigaHertz (GHz) and from 5.0 to 6.0
GHz. Any other electrical RF signal frequencies are possible. In
another exemplary embodiment, the service unit 37 provides
electrical RF service signals by generating the signals directly.
In another exemplary embodiment, the service unit 37 coordinates
the delivery of the electrical RF service signals between client
devices 24 within the antenna coverage area 20.
[0039] With continuing reference to FIG. 2, the service unit 37 is
electrically coupled to the E-O converter 28 that receives the
downlink electrical RF signals 18D from the service unit 37 and
converts them to corresponding downlink optical RF signals 22D. In
an exemplary embodiment, the E-O converter 28 includes a laser
suitable for delivering sufficient dynamic range for the RoF
applications described herein, and optionally includes a laser
driver/amplifier electrically coupled to the laser. Examples of
suitable lasers for the E-O converter 28 include, but are not
limited to, laser diodes, distributed feedback (DFB) lasers,
Fabry-Perot (FP) lasers, and vertical cavity surface emitting
lasers (VCSELs).
[0040] With continuing reference to FIG. 2, the HEU 12 also
includes the O-E converter 36, which is electrically coupled to the
service unit 37. The O-E converter 36 receives the uplink optical
RF signals 22U and converts them to corresponding uplink electrical
RF signals 18U. In an example embodiment, the O-E converter 36 is a
photodetector, or a photodetector electrically coupled to a linear
amplifier. The E-O converter 28 and the O-E converter 36 constitute
a "converter pair" 35, as illustrated in FIG. 2.
[0041] In accordance with an exemplary embodiment, the service unit
37 in the HEU 12 can include an RF signal modulator/demodulator
unit 40 for modulating/demodulating the downlink electrical RF
signals 18D and the uplink electrical RF signals 18U, respectively.
The service unit 37 can include a digital signal processing unit
("digital signal processor") 42 for providing to the RF signal
modulator/demodulator unit 40 an electrical signal that is
modulated onto an RF carrier to generate a desired downlink
electrical RF signal 18D. The digital signal processor 42 is also
configured to process a demodulation signal provided by the
demodulation of the uplink electrical RF signal 18U by the RF
signal modulator/demodulator unit 40. The HEU 12 can also include
an optional central processing unit (CPU) 44 for processing data
and otherwise performing logic and computing operations, and a
memory unit 46 for storing data, such as data to be transmitted
over a WLAN or other network for example.
[0042] With continuing reference to FIG. 2, the RAU 14 also
includes a converter pair 48 comprising the O-E converter 30 and
the E-O converter 34. The O-E converter 30 converts the received
downlink optical RF signals 22D from the HEU 12 back into downlink
electrical RF signals 50D. The E-O converter 34 converts uplink
electrical RF signals 50U received from the client device 24 into
the uplink optical RF signals 22U to be communicated to the HEU 12.
The O-E converter 30 and the E-O converter 34 are electrically
coupled to the antenna 32 via an RF signal-directing element 52,
such as a circulator for example. The RF signal-directing element
52 serves to direct the downlink electrical RF signals 50D and the
uplink electrical RF signals 50U, as discussed below. In accordance
with an exemplary embodiment, the antenna 32 can include one or
more patch antennas, such as disclosed in U.S. patent application
Ser. No. 11/504,999, filed Aug. 16, 2006 entitled "Radio-over-Fiber
Transponder With A Dual-Band Patch Antenna System," and U.S. patent
application Ser. No. 11/451,553, filed Jun. 12, 2006 entitled
"Centralized Optical Fiber-Based Wireless Picocellular Systems and
Methods," both of which are incorporated herein by reference in
their entireties.
[0043] With continuing reference to FIG. 2, the optical fiber-based
distributed communications system 10 also includes a power supply
54 that generates an electrical power signal 56. The power supply
54 is electrically coupled to the HEU 12 for powering the
power-consuming elements therein. In an exemplary embodiment, an
electrical power line 58 runs through the HEU 12 and over to the
RAU 14 to power the O-E converter 30 and the E-O converter 34 in
the converter pair 48, the optional RF signal-directing element 52
(unless the RF signal-directing element 52 is a passive device such
as a circulator for example), and any other power-consuming
elements provided. In an exemplary embodiment, the electrical power
line 58 includes two wires 60 and 62 that carry a single voltage
and that are electrically coupled to a DC power converter 64 at the
RAU 14. The DC power converter 64 is electrically coupled to the
O-E converter 30 and the E-O converter 34 in the converter pair 48,
and changes the voltage or levels of the electrical power signal 56
to the power level(s) required by the power-consuming components in
the RAU 14. In an exemplary embodiment, the DC power converter 64
is either a DC/DC power converter or an AC/DC power converter,
depending on the type of electrical power signal 56 carried by the
electrical power line 58. In another example embodiment, the
electrical power line 58 (dashed line) runs directly from the power
supply 54 to the RAU 14 rather than from or through the HEU 12. In
another example embodiment, the electrical power line 58 includes
more than two wires and carries multiple voltages.
[0044] To provide further exemplary illustration of how an optical
fiber-based distributed communications system can be deployed
indoors, FIG. 3 is provided. FIG. 3 is a partially schematic
cut-away diagram of a building infrastructure 70 employing an
optical fiber-based distributed communications system. The system
may be the optical fiber-based distributed communications system 10
of FIGS. 1 and 2. The building infrastructure 70 generally
represents any type of building in which the optical fiber-based
distributed communications system 10 can be deployed. As previously
discussed with regard to FIGS. 1 and 2, the optical fiber-based
distributed communications system 10 incorporates the HEU 12 to
provide various types of communication services to coverage areas
within the building infrastructure 70, as an example. For example,
as discussed in more detail below, the optical fiber-based
distributed communications system 10 in this embodiment is
configured to receive wireless RF signals and convert the RF
signals into RoF signals to be communicated over the optical fiber
16 to multiple RAUs 14. The optical fiber-based distributed
communications system 10 in this embodiment can be, for example, an
indoor distributed antenna system (IDAS) to provide wireless
service inside the building infrastructure 70. These wireless
signals can include cellular service, wireless services such as
RFID tracking, Wireless Fidelity (WiFi), local area network (LAN),
WLAN, and combinations thereof, as examples.
[0045] With continuing reference to FIG. 3, the building
infrastructure 70 in this embodiment includes a first (ground)
floor 72, a second floor 74, and a third floor 76. The floors 72,
74, 76 are serviced by the HEU 12 through a main distribution frame
78 to provide antenna coverage areas 80 in the building
infrastructure 70. Only the ceilings of the floors 72, 74, 76 are
shown in FIG. 3 for simplicity of illustration. In the example
embodiment, a main cable 82 has a number of different sections that
facilitate the placement of a large number of RAUs 14 in the
building infrastructure 70. Each RAU 14 in turn services its own
coverage area in the antenna coverage areas 80. The main cable 82
can include, for example, a riser cable 84 that carries all of the
downlink and uplink optical fibers 16D, 16U to and from the HEU 12.
The riser cable 84 may be routed through an interconnect unit (ICU)
85. The ICU 85 may be provided as part of or separate from the
power supply 54 in FIG. 2. The ICU 85 may also be configured to
provide power to the RAUs 14 via the electrical power line 58, as
illustrated in FIG. 2 and discussed above, provided inside an array
cable 87 and distributed with the downlink and uplink optical
fibers 16D, 16U to the RAUs 14. The main cable 82 can include one
or more multi-cable (MC) connectors adapted to connect select
downlink and uplink optical fibers 16D, 16U, along with an
electrical power line, to a number of optical fiber cables 86.
[0046] The main cable 82 enables multiple optical fiber cables 86
to be distributed throughout the building infrastructure 70 (e.g.,
fixed to the ceilings or other support surfaces of each floor 72,
74, 76) to provide the antenna coverage areas 80 for the first,
second and third floors 72, 74 and 76. In an example embodiment,
the HEU 12 is located within the building infrastructure 70 (e.g.,
in a closet or control room), while in another example embodiment
the HEU 12 may be located outside of the building infrastructure 70
at a remote location. A base transceiver station (BTS) 88, which
may be provided by a second party such as a cellular service
provider, is connected to the HEU 12, and can be co-located or
located remotely from the HEU 12. A BTS is any station or source
that provides an input signal to the HEU 12 and can receive a
return signal from the HEU 12. 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.
[0047] The optical fiber-based distributed communications system 10
in FIGS. 1-3 and described above provides point-to-point
communications between the HEU 12 and the RAU 14. Each RAU 14
communicates with the HEU 12 over a distinct downlink and uplink
optical fiber pair to provide the point-to-point communications.
Whenever an RAU 14 is installed in the optical fiber-based
distributed communications system 10, the RAU 14 is connected to a
distinct downlink and uplink optical fiber pair connected to the
HEU 12. The downlink and uplink optical fibers may be provided in
the optical fiber 16. Multiple downlink and uplink optical fiber
pairs can be provided in a fiber optic cable to service multiple
RAUs 14 from a common fiber optic cable. For example, with
reference to FIG. 3, RAUs 14 installed on a given floor 72, 74, or
76 may be serviced from the same optical fiber 16. In this regard,
the optical fiber 16 may have multiple nodes where distinct
downlink and uplink optical fiber pairs can be connected to a given
RAU 14.
[0048] It may be desirable to provide both digital data services
and RF communication services for client devices. For example, it
may be desirable to provide digital data services and RF
communication services in the building infrastructure 70 to client
devices located therein. Wired and wireless devices may be located
in the building infrastructure 70 that are configured to access
digital data services. Examples of digital data services include,
but are not limited to, Ethernet, WLAN, WiMax, WiFi, 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. Example of
digital data devices include, but are not limited to, wired and
wireless servers, wireless access points (WAPs), gateways, desktop
computers, hubs, switches, remote radio heads (RRHs), baseband
units (BBUs), and femtocells. A separate digital data services
network can be provided to provide digital data services to digital
data devices.
[0049] In this regard, embodiments disclosed herein provide optical
fiber-based distributed communications systems that support both RF
communication services and digital data services. The RF
communication services and digital data services can be distributed
over optical fiber to client devices, such as remote antenna units
for example. Digital data services can be distributed over optical
fiber separate from the optical fiber distributing RF communication
services. Alternatively, digital data services can be both
distributed over common optical fiber with RF communication
services in an optical fiber-based distributed communications
system. For example, digital data services can be distributed over
common optical fiber with RF communication services at different
wavelengths through wavelength-division multiplexing (WDM) and/or
at different frequencies through frequency-division multiplexing
(FDM).
[0050] FIG. 4 is a schematic diagram of an exemplary embodiment of
providing digital data services over separate downlink and uplink
optical fibers from radio frequency (RF) communication services to
RAUs in an optical fiber-based distributed communications system
90. The optical fiber-based distributed communications system 90
includes some optical communication components provided in the
optical fiber-based distributed communications system 10 of FIGS.
1-3. These common components are illustrated in FIG. 4 with common
element numbers with FIGS. 1-3. As illustrated in FIG. 4, the HEU
12 is provided. The HEU 12 receives the downlink electrical RF
signals 18D from the BTS 88. As previously discussed, the HEU 12
converts the downlink electrical RF signals 18D to downlink optical
RF signals 22D to be distributed to the RAUs 14. The HEU 12 is also
configured to convert the uplink optical RF signals 22U received
from the RAUs 14 into uplink electrical RF signals 18U to be
provided to the BTS 88 and on to a network 93 connected to the BTS
88. A patch panel 92 may be provided to receive the downlink and
uplink optical fibers 16D, 16U configured to carry the downlink and
uplink optical RF signals 22D, 22U. The downlink and uplink optical
fibers 16D, 16U may be bundled together in one or more riser cables
84 and provided to one or more ICU 85, as previously discussed and
illustrated in FIG. 3.
[0051] To provide digital data services in the optical fiber-based
distributed communications system 90 in this embodiment, a digital
data service controller (also referred to as "DDS controller") in
the form of a head-end media converter (HMC) 94 in this example is
provided. The DDS controller 94 can include only a media converter
for provision media conversion functionality or can include
additional functionality to facilitate digital data services. A DDS
controller is a controller configured to provide digital data
services over a communications link, interface, or other
communications channel or line, which may be either wired,
wireless, or a combination of both. FIG. 5 illustrates an example
of the HMC 94. The HMC 94 includes a housing 95 configured to house
digital media converters (DMCs) 97 to interface to a digital data
services switch 96 to support and provide digital data services.
For example, the digital data services switch 96 could be an
Ethernet switch. The digital data services switch 96 may be
configured to provide Gigabit (Gb) Ethernet digital data service as
an example. The DMCs 97 are configured to convert electrical
digital signals to optical digital signals, and vice versa. The
DMCs 97 may be configured for plug and play installation (i.e.,
installation and operability without user configuration required)
into the HMC 94. FIG. 6 illustrates an exemplary DMC 97 that can be
disposed in the housing 95 of the HMC 94. For example, the DMC 97
may include Ethernet input connectors or adapters (e.g., RJ-45) and
optical fiber output connectors or adapters (e.g., LC, SC, ST,
MTP).
[0052] With reference to FIG. 4, the HMC 94 (via the DMCs 97) in
this embodiment is configured to convert downlink electrical
digital signals (or downlink electrical digital data services
signals) 98D over digital line cables 99 from the digital data
services switch 96 into downlink optical digital signals (or
downlink optical digital data services signals) 100D that can be
communicated over downlink optical fiber 102D to RAUs 14. The HMC
94 (via the DMCs 97) is also configured to receive uplink optical
digital signals 100U from the RAUs 14 via the uplink optical fiber
102U and convert the uplink optical digital signals 100U into
uplink electrical digital signals 98U to be communicated to the
digital data services switch 96. In this manner, the digital data
services can be provided over optical fiber as part of the optical
fiber-based distributed communications system 90 to provide digital
data services in addition to RF communication services. Client
devices located at the RAUs 94 can access these digital data
services and/or RF communication services depending on their
configuration. For example, FIG. 7 illustrates the building
infrastructure 70 of FIG. 3, but with illustrative examples of
digital data services and digital client devices that can be
provided to client devices in addition to RF communication services
in the optical fiber-based distributed communications system 90. As
illustrated in FIG. 7, exemplary digital data services include WLAN
106, femtocells 108, gateways 110, baseband units (BBU) 112, remote
radio heads (RRH) 114, and servers 116.
[0053] With reference back to FIG. 4, in this embodiment, the
downlink and uplink optical fibers 102D, 102U are provided in a
fiber optic cable 104 that is interfaced to the ICU 85. The ICU 85
provides a common point in which the downlink and uplink optical
fibers 102D, 102U carrying digital optical signals can be bundled
with the downlink and uplink optical fibers 16U, 16D carrying RF
optical signals. One or more of the fiber optic cables 104, also
referenced herein as array cables 104, can be provided containing
the downlink and uplink optical fibers 16D, 16U for RF
communication services and downlink and uplink optical fibers 102D,
102U for digital data services to be routed and provided to the
RAUs 14. Any combination of services or types of optical fibers can
be provided in the array cable 104. For example, the array cable
104 may include single mode and/or multi-mode optical fibers for RF
communication services and/or digital data services.
[0054] Examples of ICUs that may be provided in the optical
fiber-based distributed communications system 90 to distribute both
downlink and uplink optical fibers 16D, 16U for RF communication
services and downlink and uplink optical fibers 102D, 102U for
digital data services are described in U.S. patent application Ser.
No. 12/466,514 filed on May 15, 2009 and entitled "Power
Distribution Devices, Systems, and Methods For Radio-Over-Fiber
(RoF) Distributed Communication," incorporated herein by reference
in its entirety, and U.S. Provisional Patent Application Ser. No.
61/330,385, filed on May 2, 2010 and entitled "Power Distribution
in Optical Fiber-based Distributed Communication Systems Providing
Digital Data and Radio-Frequency (RF) Communication Services, and
Related Components and Methods," both of which are incorporated
herein by reference in their entireties.
[0055] With continuing reference to FIG. 4, some RAUs 14 can be
connected to access points (APs) 118 or other devices supporting
digital data services. APs 118 are illustrated, but the APs 118
could be any other device supporting digital data services. In the
example of APs, the APs 118 provide access to the digital data
services provided by the digital data services switch 96. This is
because the downlink and uplink optical fibers 102D, 102U carrying
downlink and uplink optical digital signals 100D, 100U converted
from downlink and uplink electrical digital signals 98D, 98U from
the digital data services switch 96 are provided to the APs 118 via
the array cables 104 and RAUs 14. Digital data client devices can
access the APs 118 to access digital data services provided through
the digital data services switch 96.
[0056] Digital data service clients, such as APs, require power to
operate and to receive digital data services. By providing digital
data services as part of an optical fiber-based distributed
communications system, power distributed to the RAUs in the optical
fiber-based distributed communications system can also be used to
provide access to power for digital data service clients. This may
be a convenient method of providing power to digital data service
clients as opposed to providing separate power sources for digital
data service clients. For example, power distributed to the RAUs 14
in FIG. 4 by or through the ICU 85 can also be used to provide
power to the APs 118 located at RAUs 14 in the optical fiber-based
distributed communications system 90. In this regard, the ICUs 85
may be configured to provide power for both RAUs 14 and the APs
118. A power supply may be located within the ICU 85, but could
also be located outside of the ICU 85 and provided over an
electrical power line 120, as illustrated in FIG. 4. The ICU 85 may
receive either alternating current (AC) or direct current (DC)
power. The ICU 85 may receive 110 Volts (V) to 240V AC or DC power.
The ICU 85 can be configured to produce any voltage and power level
desired. The power level is based on the number of RAUs 14 and the
expected loads to be supported by the RAUs 14 and any digital
devices connected to the RAUs 14 in FIG. 4. It may further be
desired to provide additional power management features in the ICU
85. For example, one or more voltage protection circuits may be
provided.
[0057] FIG. 8 is a schematic diagram of exemplary internal
components in the RAU 14 of FIG. 4 to further illustrate how the
downlink and uplink optical fibers 16D, 16D for RF communications,
the downlink and uplink optical fibers 102D, 102U for digital data
services, and electrical power are provided to the RAU 14 and can
be distributed therein. As illustrated in FIG. 8, the array cable
104 is illustrated that contains the downlink and uplink optical
fibers 16D, 16D for RF communications, the downlink and uplink
optical fibers 102D, 102U for digital data services, and the
electrical power line 58 (see also, FIG. 2) carrying power from the
ICU 85. As previously discussed in regard to FIG. 2, the electrical
power line 58 may comprise two wires 60, 62, which may be copper
lines for example.
[0058] The downlink and uplink optical fibers 16D, 16U for RF
communications, the downlink and uplink optical fibers 102D, 102U
for digital data services, and the electrical power line 58 come
into a housing 124 of the RAU 14. The downlink and uplink optical
fibers 16D, 16U for RF communications are routed to the O-E
converter 30 and E-O converter 34, respectively, and to the antenna
32, as also illustrated in FIG. 2 and previously discussed. The
downlink and uplink optical fibers 102D, 102U for digital data
services are routed to a digital data services interface 126
provided as part of the RAU 14 to provide access to digital data
services via a port 128, which will be described in more detail
below. The electrical power line 58 carries power that is
configured to provide power to the O-E converter 30 and E-O
converter 34 and to the digital data services interface 126. In
this regard, the electrical power line 58 is coupled to a voltage
controller 130 that regulates and provides the correct voltage to
the O-E converter 30 and E-O converter 34 and to the digital data
services interface 126 and other circuitry in the RAU 14.
[0059] In this embodiment, the digital data services interface 126
is configured to convert downlink optical digital signals 100D on
the downlink optical fiber 102D into downlink electrical digital
signals 132D that can be accessed via the port 128. The digital
data services interface 126 is also configured to convert uplink
electrical digital signals 132U received through the port 128 into
uplink optical digital signals 100U to be provided back to the HMC
94 (see FIG. 4). In this regard, a media converter 134 is provided
in the digital data services interface 126 to provide these
conversions. The media converter 134 contains an O-E digital
converter 136 to convert downlink optical digital signals 100D on
the downlink optical fiber 102D into downlink electrical digital
signals 132D. The media converter 134 also contains an E-O digital
converter 138 to convert uplink electrical digital signals 132U
received through the port 128 into uplink optical digital signals
100U to be provided back to the HMC 94. In this regard, power from
the electrical power line 58 is provided to the digital data
services interface 126 to provide power to the O-E digital
converter 136 and E-O digital converter 138.
[0060] Because electrical power is provided to the RAU 14 and the
digital data services interface 126, this also provides an
opportunity to provide power for digital devices connected to the
RAU 14 via the port 128. In this regard, a power interface 140 is
also provided in the digital data services interface 126, as
illustrated in FIG. 8. The power interface 140 is configured to
receive power from the electrical power line 58 via the voltage
controller 130 and to also make power accessible through the port
128. In this manner, if a client device contains a compatible
connector to connect to the port 128, not only will digital data
services be accessible, but power from the electrical power line 58
can also be accessed through the same port 128. Alternatively, the
power interface 140 could be coupled to a separate port from the
port 128 for digital data services.
[0061] For example, if the digital data services are provided over
Ethernet, the power interface 140 could be provided as a
Power-over-Ethernet (PoE) interface. The port 128 could be
configured to receive a RJ-45 Ethernet connector compatible with
PoE as an example. In this manner, an Ethernet connector connected
into the port 128 would be able to access both Ethernet digital
data services to and from the downlink and uplink optical fibers
102D, 102U to the HMC 94 as well as access power distributed by the
ICU 85 over the array cable 104 provided by the electrical power
line 58.
[0062] Further, the HEU 12 could include low level control and
management of the media converter 134 using communication supported
by the HEU 12. For example, the media converter 134 could report
functionality data (e.g., power on, reception of optical digital
data, etc.) to the HEU 12 over the uplink optical fiber 16U that
carries communication services. The RAU 14 can include a
microprocessor that communicates with the media converter 134 to
receive this data and communicate this data over the uplink optical
fiber 16U to the HEU 12.
[0063] Other configurations are possible to provide digital data
services in an optical fiber-based distributed communications
system. For example, FIG. 9 is a schematic diagram of another
exemplary embodiment of providing digital data services in an
optical fiber-based distributed communications system configured to
provide RF communication services. In this regard, FIG. 9 provides
an optical fiber-based distributed communications system 150. The
optical fiber-based distributed communications system 150 may be
similar to and include common components provided in the optical
fiber-based distributed communications system 90 in FIG. 4. In this
embodiment, instead of the HMC 94 being provided separate from the
HEU 12, the HMC 94 is co-located with the HEU 12. The downlink and
uplink optical fibers 102D, 102U for providing digital data
services from the digital data services switch 96 are also
connected to the patch panel 92. The downlink and uplink optical
fibers 16D, 16U for RF communications and the downlink and uplink
optical fibers 102D, 102U for digital data services are then routed
to the ICU 85, similar to FIG. 2.
[0064] The downlink and uplink optical fibers 16D, 16U for RF
communications, and the downlink and uplink optical fibers 102D,
102U for digital data services, may be provided in a common fiber
optic cable or provided in separate fiber optic cables. Further, as
illustrated in FIG. 9, standalone media converters (MCs) 141 may be
provided separately from the RAUs 14 in lieu of being integrated
with RAUs 14, as illustrated in FIG. 4. The stand alone MCs 141 can
be configured to contain the same components as provided in the
digital data services interface 126 in FIG. 8, including the media
converter 134. The APs 118 may also each include antennas 152 to
provide wireless digital data services in lieu of or in addition to
wired services through the port 128 through the RAUs 14.
[0065] FIG. 10A is a schematic diagram of another exemplary
embodiment of providing digital data services in an optical
fiber-based distributed communications system. In this regard, FIG.
10A provides an optical fiber-based distributed communications
system 160. The optical fiber-based distributed communications
system 160 may be similar to and include common components provided
in the optical fiber-based distributed communications systems 90,
150 in FIGS. 4 and 9.
[0066] In this embodiment, as illustrated in FIG. 10A,
wavelength-division multiplexing (WDM) is employed to multiplex
digital data services and RF communication services together at
different wavelengths over downlink and uplink optical fibers
162D(1-N), 162U(1-N) in the optical fiber-based distributed
communications system 160. "1-N" downlink and uplink optical fiber
pairs are provided to the ICU 85 to be distributed to the RAUs 14
and stand alone MCs 141. Multiplexing could be used to further
reduce the cost for the digital data services overlay. By using
WDM, digital data signals are transmitted on the same optical
fibers as the RF communication signals, but on different
wavelengths. Separate media conversion and WDM filters at the
transmit locations and at the receive locations (e.g., HMC 96 and
RAUs 14) would be employed to receive signals at the desired
wavelength.
[0067] The HMC 94 and HEU 12 are co-located in the optical
fiber-based distributed communications system 160 in FIG. 10A. A
plurality of wavelength-division multiplexers 164(1)-164(N) are
provided that each multiplex the downlink optical RF signal(s) 22D
for RF communications and the downlink optical digital signal(s)
100D for digital data services together on a common downlink
optical fiber(s) 162D(1-N). Similarly, a plurality of
wavelength-division de-multiplexers 168(1)-168(N) (e.g., wavelength
filters) are provided that each de-multiplex the uplink optical RF
signal(s) 22U from the uplink optical digital signal(s) 100U from a
common uplink optical fiber(s) 162U(1-N) to provide the uplink
optical RF signals 22U to the HEU 12 and the uplink optical digital
signal 100U to the HMC 94. Wavelength-division de-multiplexing
(WDD) and WDM are also employed in the RAUs 14 to de-multiplex
multiplexed downlink optical RF signals 22D and downlink optical
digital signals 100D on the common downlink optical fibers
162D(1-N) and to multiplex uplink optical RF signals 22U and uplink
optical digital signals 100U on the common uplink optical fibers
162U(1-N).
[0068] FIG. 10B is a schematic diagram of another exemplary
embodiment of providing digital data services in an optical
fiber-based distributed communications system 160'. The optical
fiber-based distributed communications system 160' in FIG. 10B is
the same as the optical fiber-based distributed communications
system 160 in FIG. 10A, except that WDM is employed to multiplex
uplink and downlink communication services at different wavelengths
over common optical fiber that includes both downlink and uplink
optical fibers 162D(1-N), 162U(1-N),
[0069] FIG. 11 is a schematic diagram of another exemplary
embodiment of providing digital data services in an optical
fiber-based distributed communications system. As illustrated in
FIG. 11, an optical fiber-based distributed communications system
170 is provided that can also deliver digital data services.
Instead of wavelength-division multiplexing the downlink optical RF
signal(s) 22D for RF communications with the downlink optical
digital signal(s) 100D for digital data services together on a
common downlink optical fiber(s) 162D(1-N) as provided in FIG. 10A,
a wavelength-division multiplexer 172 is provided. The
wavelength-division multiplexer 172 multiplexes all downlink
optical RF signals 22D with all downlink optical digital signal
100D to a single downlink optical fiber 174D. Similarly, a
wavelength-division de-multiplexer 176 is provided to de-multiplex
all uplink optical RF signals 22U from all uplink optical digital
signals 100U from the common uplink optical fiber 174U at the
desired wavelength. A wavelength-division de-multiplexer 175 and a
wavelength-division multiplexer 177 are also employed in the ICU 85
to de-multiplex wavelength-division multiplexed downlink optical RF
signals 22D and uplink optical digital signals 100U on the common
downlink optical fiber 174D, and to wavelength-division multiplex
uplink optical RF signals 22U and uplink optical digital signals
100U on the common uplink optical fiber 174U, respectively.
[0070] Alternatively, WDD and WDM could also be employed in the
RAUs 14 to de-multiplex wavelength-division multiplexed downlink
optical RF signals 22D and downlink optical digital signals 100D on
the common downlink optical fiber 174D, and to wavelength-division
multiplex uplink optical RF signals 22U and uplink optical digital
signals 100U on the common uplink optical fiber 174U. In this
alternative embodiment, de-multiplexing at the RAUs 14 could be
done where a common WDM signal would be distributed from RAU 14 to
RAU 14 in a daisy-chain configuration. Alternatively, optical
splitters could be employed at break-out points in the fiber optic
cable 104.
[0071] FIG. 12 is a schematic diagram of another exemplary
embodiment of providing digital data services in an optical
fiber-based distributed communications system. As illustrated in
FIG. 12, an optical fiber-based distributed communications system
180 is provided that can also deliver digital data services. The
optical fiber-based distributed communications system 180 is the
same as the optical fiber-based distributed communications system
170 in FIG. 11, except that the HEU 12 and HMC 94 are provided in a
common housing 182 that also houses the wavelength-division
multiplexer 172 and wavelength-division de-multiplexer 176.
Alternatively, a plurality of wavelength-division multiplexers and
plurality of wavelength-division de-multiplexers like provided in
FIG. 10A (164(1-N)) and 168(1-N)) can be provided in the common
housing 182.
[0072] FIG. 13 is a schematic diagram of another exemplary
embodiment of an optical fiber-based distributed communications
system providing digital data services. As illustrated in FIG. 13,
an optical fiber-based distributed communications system 190 is
provided. In this embodiment, frequency-division multiplexing (FDM)
is employed to multiplex digital data services and RF communication
services at different frequencies over downlink optical fibers and
uplink optical fibers. One advantage of employing FDM is that E-O
converters would be used simultaneously for converting RF
communication signals and digital data signals into respective
optical signals. Therefore, additional media converters for
converting electrical digital signals to optical digital signals
can be avoided to reduce complexity and save costs. For example,
fast Ethernet (e.g., 100 Megabits/second (Mbs)) could be
transmitted below the cellular spectrum (e.g., below 700 MHz). More
than one (1) channel could be transmitted simultaneously in this
frequency range.
[0073] In this regard, the HEU 12 and HEC 94 are both disposed in
the common housing 182, as illustrated in FIG. 13. A plurality of
frequency-division multiplexers 192(1-N) are provided in the common
housing 182 and are each configured to multiplex the downlink
electrical digital signal(s) 98D with the downlink electrical RF
signal(s) 18D at different frequencies prior to optical conversion.
In this manner, after optical conversion, a common optical fiber
downlink 194D(1-N) can carry frequency-division multiplexed
downlink optical RF signal 22D and downlink optical digital signal
102D on the same downlink optical fiber 194D(1-N). Similarly, a
plurality of frequency-division de-multiplexers 196(1-N) are
provided in the common housing 182 to de-multiplex an uplink
optical RF signal 22U and an uplink optical digital signal 100U on
an uplink optical fiber 194U(1-N). Frequency-division
de-multiplexing (FDD) and FDM are also employed in the RAUs 14. FDD
is employed in the RAU 14 to de-multiplex frequency multiplexed
downlink electrical RF signals 18D and downlink electrical digital
signals 98D after being converted from optical signals from the
common downlink optical fiber 174D to electrical signals. FDM is
also provided in the RAU 14 to frequency multiplex uplink
electrical signals in the RAU 14 before being converted to uplink
optical RF signals 22U and uplink optical digital signals 100U
provided on the common uplink optical fiber 174U.
[0074] FIG. 14 is a schematic diagram of another exemplary
embodiment of an optical fiber-based distributed communications
system that employs both WDM and FDM. In this regard, FIG. 14
illustrates an optical fiber-based distributed communications
system 200. The optical fiber-based distributed communications
system 200 employs the WDM and WDD of the optical fiber-based
distributed communications system 180 of FIG. 12 combined with FDM
and FDD of the optical fiber-based distributed communications
system 190 of FIG. 13. The wavelength-division multiplexed and
frequency-division multiplexed downlink signals are provided over
downlink optical fiber 202D. The wavelength-division multiplexed
and frequency-division multiplexed uplink signals are provided over
uplink optical fiber 202U.
[0075] Options and alternatives can be provided for the
above-described embodiments. A digital data services interface
provided in an RAU or stand alone MC could include more than one
digital data services port. For example, referring to FIG. 14 as an
example, a switch 203, such as an Ethernet switch for example, may
be disposed in the RAUs 14 to provide RAUs 14 that can support more
than one digital data services port. An HMC could have an
integrated Ethernet switch so that, for example, several APs could
be attached via cables (e.g., Cat 5/6/7 cables) in a star
architecture. The Ethernet channel could be used for control,
management, and/or communication purposes for an optical
fiber-based distributed communications system as well as the
Ethernet media conversion layer. The HMC could be either single
channel or multi-channel (e.g., twelve (12) channel) solutions. The
multi-channel solution may be cheaper per channel than a single
channel solution. Further, uplink and downlink electrical digital
signals can be provided over mediums other than optical fiber,
including electrical conducting wire and/or wireless
communications, as examples.
[0076] Frequency up conversions or down conversions may be employed
when providing FDM if RF communication signals have frequencies too
close to the frequencies of the digital data signals to avoid
interference. While digital baseband transmission of a baseband
digital data signals below the spectrum of the RF communication
signals can be considered, intermodulation distortion on the RF
communication signals may be generated. Another approach is to up
convert the digital data signals above the frequencies of the RF
communication signals and also use, for example, a constant
envelope modulation format for digital data signal modulation.
Frequency Shift Keying (FSK) and Minimum Shift Keying (MSK)
modulation are suitable examples for such modulation formats.
Further, in the case of FDM for digital data services, higher-level
modulation formats can be considered to transmit high data rates
(e.g., one (1) Gb, or ten (10) Gb) over the same optical fiber as
the RF communication signals. Multiple solutions using
single-carrier (with e.g., 8-FSK or 16-QAM as examples) or
multi-carrier (OFDM) are conceivable.
[0077] Further, as used herein, it is intended that 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. The
optical fibers disclosed herein can be single mode or multi-mode
optical fibers. Likewise, other types of suitable optical fibers
include bend-insensitive optical fibers, or any other expedient of
a medium for transmitting light signals. An example of a
bend-insensitive, or bend resistant, optical fiber is
ClearCurve.RTM. Multimode fiber commercially available from Corning
Incorporated. Suitable fibers of this type are disclosed, for
example, in U.S. Patent Application Publication Nos. 2008/0166094
and 2009/0169163, the disclosures of which are incorporated herein
by reference in their entireties.
[0078] Many modifications and other embodiments of the embodiments
set forth herein will come to mind to one skilled in the art to
which the embodiments pertain having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. Therefore, it is to be understood that the description
and claims are not to be limited to the specific embodiments
disclosed and that modifications and other embodiments are intended
to be included within the scope of the appended claims. It is
intended that the embodiments cover the modifications and
variations of the embodiments provided they come within the scope
of the appended claims and their equivalents. Although specific
terms are employed herein, they are used in a generic and
descriptive sense only and not for purposes of limitation.
* * * * *