U.S. patent application number 15/358060 was filed with the patent office on 2017-08-31 for virtual radio access network using software-defined network of remotes and digital multiplexing switches.
The applicant listed for this patent is Dali Systems Co. Ltd.. Invention is credited to Shawn Patrick Stapleton, Sasa Trajkovic.
Application Number | 20170250927 15/358060 |
Document ID | / |
Family ID | 59680260 |
Filed Date | 2017-08-31 |
United States Patent
Application |
20170250927 |
Kind Code |
A1 |
Stapleton; Shawn Patrick ;
et al. |
August 31, 2017 |
VIRTUAL RADIO ACCESS NETWORK USING SOFTWARE-DEFINED NETWORK OF
REMOTES AND DIGITAL MULTIPLEXING SWITCHES
Abstract
A system for routing signals in a Distributed Antenna System
(DAS) includes one or more Base Band Units (BBUs). Each of the one
or more BBUs has one or more digital outputs. The system also
includes a plurality of Digital Multiplexer Units (DMUs) coupled to
each other and operable to route signals between the plurality of
DMUs. Each of the plurality of DMUs is operable to receive one or
more digital inputs from the one or more BBUs. The system further
includes a plurality of Digital Remote Units (DRUs) coupled to the
plurality of DMUs and operable to transport signals between the
plurality of DRUs and one or more of the plurality of DMUs.
Inventors: |
Stapleton; Shawn Patrick;
(Vancourver, CA) ; Trajkovic; Sasa; (Burnaby,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dali Systems Co. Ltd. |
George Town |
|
KY |
|
|
Family ID: |
59680260 |
Appl. No.: |
15/358060 |
Filed: |
November 21, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14580585 |
Dec 23, 2014 |
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15358060 |
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62258289 |
Nov 20, 2015 |
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61920397 |
Dec 23, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 25/02 20130101;
H04B 10/25753 20130101; H04B 7/022 20130101 |
International
Class: |
H04L 12/947 20060101
H04L012/947; H04B 10/2575 20060101 H04B010/2575; H04L 25/02
20060101 H04L025/02 |
Claims
1. A system comprising: a first fronthaul interface including a
plurality of first digital multiplexing units (DMUs), wherein each
first DMU of the plurality of first DMUs is configured to: receive
a plurality of first signals from a first baseband unit (BBU);
extract a first subset of the plurality of first signals; aggregate
the first subset of the plurality of first signals into a first
stream; and route the first stream to one or more first digital
remote units (DRUs) of a plurality of DRUs.
2. The system of claim 1, further comprising: a second fronthaul
interface including a plurality of second DMUs, wherein each second
DMU of the plurality of second DMUs is configured to: receive a
plurality of second signals from a second BBU; extract a second
subset of the plurality of second signals; aggregate the second
subset of the plurality of second signals into a second stream; and
route the second stream to one or more second DRUs of the plurality
of DRUs.
3. The system of claim 2, wherein the first fronthaul interface is
associated with a first operator, and wherein the second fronthaul
interface is associated with a second operator.
4. The system of claim 2, further comprising: a third DMU, wherein
the third DMU is located between the first fronthaul interface and
the one or more first DRUs, wherein the third DMU is located
between the second fronthaul interface and the one or more second
DRUs, and wherein the third DMU is configured to: receive the first
stream from a first DMU of the plurality of first DMUs; decompose
the first stream, wherein routing the first stream to the one or
more first DRUs is via the third DMU; receive the second stream
from a second DMU of the plurality of second DMUs; and decompose
the second stream, wherein routing the second stream to the one or
more second DRUs is via the third DMU.
5. The system of claim 4, wherein the first stream is decomposed
into the first subset of the plurality of first signals, and
wherein the second stream is decomposed into the second subset of
the plurality of second signals.
6. The system of claim 4, wherein the third DMU is collocated with
the plurality of DRUs.
7. The system of claim 6, wherein the third DMU and the plurality
of DRUs are located remotely from the first fronthaul interface and
the second fronthaul interface.
8. The system of claim 1, wherein the first BBU is a virtual
BBU.
9. The system of claim 1, wherein control & management
(C&M) functionality of each first DMU of the plurality of first
DMUs is implemented in a cloud network.
10. The system of claim 1, wherein control & management
(C&M) functionality of each DRU of the plurality of DRUs is
implemented in a cloud network.
11. The system of claim 1, wherein the first fronthaul interface is
implemented on one or more chips.
12. The system of claim 1, wherein the plurality of first signals
are a plurality of digital signals.
13. A method comprising: receiving, at a first digital multiplexing
unit (DMU), a plurality of first signals from a first baseband unit
(BBU); extracting, by the first DMU, a first subset of the
plurality of first signals; aggregating, by the first DMU, the
first subset of the plurality of first signals into a first stream;
and routing, by the first DMU, the first stream to one or more
first digital remote units (DRUs) of a plurality of DRUs.
14. The method of claim 13, wherein routing the first stream to the
one or more DRUs comprises: transmitting, by the first DMU, the
first stream to a second DMU, wherein the second DMU decomposes the
first stream and sends the first stream to the one or more first
DRUs.
15. The method of claim 14, wherein the second DMU receives a
second stream from a third DMU, decomposes the second stream and
sends the second stream to one or more second DRUs of the plurality
of DRUs.
16. The method of claim 15, wherein the first DMU and the third DMU
are associated with different operators.
17. The method of claim 14, wherein the second DMU is collocated
with the plurality of DRUs.
18. The method of claim 17, wherein the second DMU and the
plurality of DRUs are located remotely from the first DMU.
19. The method of claim 13, wherein control & management
(C&M) functionality of the first DMU is implemented in a cloud
network.
20. The method of claim 13, wherein the first DMU is included on a
chip.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 62/258,289, filed Nov. 20, 2015. This
application is also a continuation-in-part of U.S. patent
application Ser. No. 14/580,585, filed on Dec. 23, 2014, entitled
"Digital Multiplexer in a Distributed Antenna System", which claims
priority to U.S. Provisional Patent Application No. 61/920,397,
filed on Dec. 23, 2013, entitled "Digital Multiplexer in a
Distributed Antenna System". The foregoing applications are hereby
incorporated by reference in their entirety for all purposes.
BACKGROUND OF THE INVENTION
[0002] Wireless and mobile network operators face the continuing
challenge of building networks that effectively manage high
data-traffic growth rates. Mobility and an increased level of
multimedia content for end users requires end-to-end network
adaptations that support both new services and the increased demand
for broadband and flat-rate Internet access. One of the most
difficult challenges faced by network operators is caused by the
physical movement of subscribers from one location to another, and
particularly when wireless subscribers congregate in large numbers
at one location. A notable example is a business enterprise
facility during lunchtime, when a large number of wireless
subscribers visit a cafeteria location in the building. At that
time, a large number of subscribers have moved away from their
offices and usual work areas. It's likely that during lunchtime
there are many locations throughout the facility where there are
very few subscribers. If the indoor wireless network resources were
properly sized during the design process for subscriber loading as
it is during normal working hours when subscribers are in their
normal work areas, it is very likely that the lunchtime scenario
will present some unexpected challenges with regard to available
wireless capacity and data throughput.
[0003] To address these issues, Distributed Antenna Systems (DAS)
have been developed and deployed. Despite the progress made in DAS,
there is a need in the art for improved methods and systems related
to DAS.
SUMMARY OF THE INVENTION
[0004] The present invention generally relates to wireless
communication systems employing Distributed Antenna Systems (DAS)
as part of a distributed wireless network. More specifically, the
present invention relates to a DAS utilizing software defined radio
(SDR). Wireless and mobile network operators face the continuing
challenge of building networks that effectively manage high
data-traffic growth rates. Mobility and an increased level of
multimedia content for end users typically employs end-to-end
network adaptations that support new services and the increased
demand for broadband and flat-rate Internet access. Distributed
Antenna Systems (DAS) provide a mechanism to route signals to
various antennas that are distributed over a given geographical
area. The signals typically originate from a base transceiver
station (BTS), also referred to as a base station, at RF
frequencies or digitally from a Baseband Unit (BBU). The BBU is
part of a distributed Base Station system, whereby the Radio Unit
(RU) is physically separated from the BBU. This kind of distributed
architecture can increase flexibility of networking and decrease
the cost of maintaining a network. Some common interface standards
between the BBU and RU are OBSAI (Open Base Station Architecture
Initiative), CPRI (Common Public Radio Interface) and ORI (Open
Radio Interface). The cellular payload data is transported between
a plurality of BBUs and RUs at a high data rate. The BBU framed
data is comprised of: payload IQ data, Control and Management
(C&M) information, carrier frequency, signal bandwidth, etc. A
common DAS platform that interfaces between both BBUs, at baseband,
and BTSs, at RF, will simplify the distributed antenna system
architecture.
[0005] According to some embodiments of the present invention, a
system is provided. The system comprises a fronthaul interface
including a plurality of DMUs. Each DMU of the plurality of DMUs is
configured to receive a plurality of signals from a BBU, extract a
subset of the plurality of signals, aggregate the subset of the
plurality of signals into a stream, and route the stream to one or
more DRUs of a plurality of DRUs.
[0006] According to some embodiments of the present invention, a
method is provided. The method comprises receiving, at a DMU, a
plurality of signals from a BBU. The method further comprises
extracting a subset of the plurality of signals. The method further
comprises aggregating the subset of the plurality of signals into a
stream. The method further comprises routing the stream to one or
more DRUs of a plurality of DRUs.
[0007] According to an embodiment of the present invention, a
system for routing signals in a Distributed Antenna System (DAS) is
provided. The system includes one or more Base Band Units (BBUs).
Each of the one or more BBUs has one or more digital outputs. The
system also includes a plurality of Digital Multiplexer Units
(DMUs) coupled to each other and operable to route signals between
the plurality of DMUs. Each of the plurality of DMUs is operable to
receive one or more digital inputs from the one or more BBUs. The
system further includes a plurality of Digital Remote Units (DRUs)
coupled to the plurality of DMUs and operable to transport signals
between the plurality of DRUs and one or more of the plurality of
DMUs.
[0008] According to another embodiment of the present invention, a
method for routing signals in a Distributed Antenna System (DAS)
including a plurality of Digital Multiplexer Units (DMUs) and a
plurality of Digital Remote Units (DRUs) is provided. The method
includes receiving, at ports of the plurality of DMUs, digital
signals from sector ports of one or more Base Band Units (BBUs).
The method also includes routing the digital signals between the
plurality of DMUs and transporting the digital signals between the
plurality of DMUs and a plurality of DRUs.
[0009] According to a specific embodiment of the present invention,
a Distributed Antenna System (DAS) is provided. The DAS includes a
plurality of Digital Multiplexer Units (DMUs) coupled to each other
and operable to route signals between the plurality of DMUs. Each
of the plurality of DMUs includes a plurality of digital input
ports operable to receive digital inputs from one of more of a
plurality of BBUs. Each of the plurality of BBUs includes a
plurality of digital output ports. The DAS also includes a
plurality of Digital Access Units (DAUs) coupled to each other and
operable to route signals between the plurality of DAUs. Each of
the plurality of DAUs includes a plurality of analog input ports
operable to receive analog RF inputs from one of more of a
plurality of BTSs. Each of the plurality of BTSs includes a
plurality of analog RF output ports. The DAS further includes a
plurality of Digital Remote Units (DRUs) coupled to the plurality
of DMUs and operable to transport signals between DRUs and DMUs,
each of the plurality of DRUs including a remote antenna.
[0010] According to a particular embodiment of the present
invention, a system for routing signals in a Distributed Antenna
System is provided. The system includes a plurality of Digital
Multiplexer Units (DMUs). The plurality of DMUs are coupled and
operable to route signals between the plurality of DMUs. The system
also includes a plurality of Digital Remote Units (DRUs) coupled to
the plurality of DMUs and operable to transport signals between
DRUs and DMUs, a plurality of Base Band Units (BBU) with digital
connections to the plurality of DMUs and operable to route signals
between the plurality of DMUs and the plurality of digital
connections.
[0011] According to another embodiment of the present invention, a
system is provided. The system comprises a core network, a data
center in communication with the core network, and a plurality of
digital remote units (DRUs) in communication with the data center.
The data center comprises a plurality of baseband units (BBUs) and
a plurality of digital multiplexing units (DMUs). The plurality of
DMUs are configured to route I/Q data to one or more of the
plurality of DRUs. Control and management (C&M) functionality
of each DMU and DRU is located in a cloud network.
[0012] Numerous benefits are achieved by way of the present
invention over conventional techniques. For example, embodiments of
the present invention provide methods and systems that utilize
system elements with reduced hardware requirements (e.g., radio
units in BTSs and radio units in DAUs), thereby reducing system
cost, reducing system power consumption, and reducing system size.
Additionally, embodiments described herein reduce or remove the
requirement to perform RF to digital conversion and digital to RF
conversion, thereby reducing signal degradation. These and other
embodiments of the invention along with many of its advantages and
features are described in more detail in conjunction with the text
below and attached figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Further objects and advantages of the present invention can
be more fully understood from the following detailed description
taken in conjunction with the accompanying drawings in which:
[0014] FIG. 1 is a block diagram according to one embodiment of the
invention showing the basic structure and an example of the
transport routing based on having a single 3 sector BBU with 3 DMUs
and 7 DRUs daisy chained together for each cell.
[0015] FIG. 2 is a block diagram according to one embodiment of the
invention showing the basic structure for a frequency reuse pattern
of N=1 and an example of the transport routing based on having a
single 3 sector BBU with 3 DMUs and 7 DRUs daisy chained together
for each cell.
[0016] FIG. 3 is a block diagram according to one embodiment of the
invention showing the basic structure and an example of the
transport routing based on having multiple 3 sector BBUs with 3
DMUs and 7 DRUs daisy chained together for each cell.
[0017] FIG. 4 is a block diagram of a Digital Access Unit (DAU),
which contains Physical Nodes and a Local Router according to an
embodiment of the present invention.
[0018] FIG. 5 is a block diagram of a Digital Remote Unit (DRU)
according to an embodiment of the present invention.
[0019] FIG. 6 depicts a typical topology where multiple Local
Routers (DMUs and DAUs) are interconnected with multiple Remote
Routers according to an embodiment of the present invention.
[0020] FIG. 7 shows a block diagram of the interconnection between
a BTS to DAUs and a BBU to DMUs.
[0021] FIG. 8 is a block diagram of a Digital Multiplexer Unit
(DMU) according to an embodiment of the present invention.
[0022] FIG. 9 is a simplified flowchart illustrating a method of
routing signals in a DAS according to an embodiment of the present
invention.
[0023] FIG. 10 is a schematic block diagram illustrating a Radio
Access Network (RAN) according to an embodiment of the present
invention.
[0024] FIG. 11 is a schematic block diagram illustrating a
Centralized RAN (C-RAN) according to an embodiment of the present
invention.
[0025] FIG. 12 is a schematic block diagram illustrating a
multi-operator C-RAN according to an embodiment of the present
invention.
[0026] FIG. 13 is a schematic block diagram illustrating a Cloud
RAN according to an embodiment of the present invention.
[0027] FIG. 14 is a simplified flowchart illustrating a method of
control and management (C&M) of the RAN according to an
embodiment of the present invention.
[0028] FIG. 15 is a screen shot illustrating a user interface for
control and management of a DMU according to an embodiment of the
present invention.
[0029] FIG. 16 is a screen shot illustrating a user interface for
control and management of a DRU according to an embodiment of the
present invention.
[0030] FIG. 17 is a schematic block diagram illustrating a Cloud
RAN in a metro network according to an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] A distributed antenna system (DAS) provides an efficient
means of utilization of base station resources. The base station or
base stations associated with a DAS can be located in a central
location and/or facility commonly known as a base station hotel. A
traditional DAS network includes one or more digital access units
(DAUs) that function as the interface between the base stations and
the digital remote units (DRUs). The DAUs can be collocated with
the base stations. The DRUs can be daisy chained together and/or
placed in a star configuration and provide coverage for a given
geographical area. The DRUs are typically connected with the DAUs
by employing a high-speed optical fiber link. This approach
facilitates transport of the RF signals from the base stations to a
remote location or area served by the DRUs. A typical base station
comprises 3 independent radio resources, commonly known as sectors.
These 3 sectors are typically used to cover 3 separate geographical
areas without creating co-channel interference between users in the
3 distinct sectors.
[0032] A Distributed Base Station Architecture involves the use of
Base Band Units (BBUs) and many remotely located Radio Units (RUs).
A number of standards exist for interfacing BBUs to RUs, some
examples are OBSAI (Open Base Station Architecture Initiative),
CPRI (Common Public Radio Interface) and ORI (Open Radio
Interface). Traditionally, a Distributed Base Station Architecture
and a Distributed Antenna System (DAS) do not coexist on the same
system. Typically, the distributed Base Station Architecture
involves vendor specific infrastructure and cannot accommodate
remote radio unit sharing. This poses a problem when venues have
requirements that limit the number of antennas and remote units
because of issues such as space constraints, esthetics constraints,
etc. Infrastructure sharing is a means of reducing the number
visible vendor specific units in a given outdoor or indoor venue. A
Distributed Antenna System is preferably vendor and modulation
agnostic in order to accommodate all the different vendor specific
interfaces. Capturing the signals from the various vendor BTSs at
RF is a means of ensuring that the DAS system will be agnostic.
However, an active DAS system will digitize the RF signals and
transport them to the remote units, whereby they will be translated
back to RF. A Digital Access Unit (DAU) is the host unit that
accepts the RF signals from the various BTSs.
[0033] The BTS includes a BBU and a collocated Radio Unit. The
various Radio Units of multiple vendor BTSs interface to the DAUs
at RF. A more efficient process would be to utilize a Digital
Multiplexer Unit (DMU) that digitally interfaces directly to the
vendor BBUs. This architecture would eliminate the requirement of
the BTS to translate the signal to RF and then have the DAU
translate the signal back to digital baseband. The net effect would
be to remove any impairment that occurs through the translation
process in addition to reducing the power consumption of this
additional step. This DMU would be able to interface to the various
vendor BBUs. The DMU serves another key function; it collates the
various operator channels onto a single data stream that is sent to
the various remote units. The remote unit radio channels are shared
amongst the various operators. The reverse operation would occur in
the DMU, whereby the received uplink signals from the various
remote units are transported back to the DMU and then distributed
to a specific BBU. An additional feature of the DMU is that it can
interface to DAUs when a system has legacy BTS equipment that
requires an RF interface.
[0034] An embodiment shown in FIG. 1 illustrates a basic DAS
network architecture according to an embodiment of the present
invention and provides an example of a data transport scenario
between a 3 sector BBU and multiple DRUs. In this embodiment, the
DRUs are daisy chained together to achieve coverage in a specific
geographical area. Each individual sector covers an independent
geographical area, which is identified as a Cell.
[0035] FIG. 1 depicts a DAS system employing multiple Digital
Remote Units (DRUs) and multiple Digital Multiplexer Units (DMUs).
In accordance with the present invention, each DRU provides unique
header information associated with each DRU which uniquely
identifies uplink data received by that particular Digital Remote
Unit.
[0036] One feature of embodiments of the present invention is the
ability to route Base Station radio resources among the DRUs or
group(s) of DRUs. In order to route radio resources available from
one or more Base Stations, it is desirable to configure the
individual router tables of the DMUs and DRUs in the DAS
network.
[0037] The DMUs 102, 108, and 111 are networked together to
facilitate the routing of DRU signals among the multiple DMUs. The
DMUs support the transport of the RF downlink and RF uplink signals
between the BBU and the DRUs. This architecture enables the various
base band unit signals to be transported simultaneously or
concurrently to and from multiple DRUs. PEER ports are used for
interconnecting DMUs and interconnecting DRUs in some
embodiments.
[0038] The DMUs have the capability to control the gain (in small
increments over a wide range) of the downlink and uplink signals
that are transported between the DMU and the base band unit (or
base band units) connected to that DMU. This capability provides
flexibility to simultaneously control the uplink and downlink
connectivity of the path between a particular DRU (or a group of
DRUs via the associated DMU or DMUs) and a particular base band
unit sector.
[0039] Embodiments of the present invention use router tables to
configure the networked DMUs. The local router tables establish the
mapping of the inputs to the various outputs. Internal Merge blocks
are utilized for the Downlink Tables when the inputs from an
External Port and a PEER Port need to merge into the same data
stream. Similarly, Merge blocks are used in the Uplink Tables when
the inputs from the LAN Ports and PEER Ports need to merge into the
same data stream.
[0040] The remote router tables establish the mapping of the inputs
to the various outputs. Internal Merge blocks are utilized for the
Downlink Tables when the inputs from a LAN Port and a PEER Port
need to merge into the same data stream. Similarly, Merge blocks
are used in the Uplink Tables when the inputs from the External
Ports and PEER Ports need to merge into the same data stream.
[0041] As shown in FIG. 1, the individual base band unit sector's
radio resources are transported to a daisy-chained network of DRUs.
Each individual sector's radio resources provide coverage to an
independent geographical area via the networked DRUs. FIG. 1
demonstrates how three cells, each cell comprising an independent
network of 7 DRUs, provide coverage to a given geographical area. A
server 112 is utilized to control the switching function provided
in the DAS network. Referring to FIG. 1 and by way of example, DMU
1 (102) receives digital downlink signals from BBU Sector 1 (101).
DMU 1 collates the baseband signals from the other DMUs onto a
serial stream and the optical fiber cable 123 transports the
desired digital signals to DRU 2 (104). Optical cable 105
transports all the digital optical signals to DRU 3 (106). The
other DRUs in the daisy chain are involved in passing the optical
signals onward to DRU 1 (107). Thus, embodiments of the present
invention provide the ability to receive digital signals from a
plurality of sectors of a BBU of a base station (e.g., Sector 1
(101), Sector 2 (109), and Sector 3 (110). The digital signals are
received by one or more DMUs, which are connected to each other and
controlled by server 112 so that the digital signals can be routed
between the DMUs. The digital signals, which may be processed at
the DMU, are then routed to the digital remote units, illustrated
by DRU1 through DRU21 in FIG. 1.
[0042] DMU 1 (102) is networked with DMU 2 (108) and DMU 3 (111) to
allow the downlink signals from Sector 2 (109) and Sector 3 (110)
to be transported to all the DRUs in Cell 1. The system's switching
and routing functions enable the selection of which sectors'
signals are transmitted and received by each DRU. DMU 2 (108) is
connected to Cell 3 (DRUs 15-21) using optical cable 124 and DMU 3
(111) is connected to Cell 2 (DRUs 8-14) using optical cable
125.
[0043] Because the DMUs receive digital signals from the base band
units, for example, over optical fiber, although other
communications media can be used, they are able to process the
received digital signals and transmit digital signals to the DRUs
for broadcast as RF signals to users. Although embodiments of the
present invention discuss receiving and transmitting digital
signals, it is not necessary that these digital signals be
identical since processed versions of received digital signals can
be transmitted, which can also be referred to as digital signals.
As an example, digital signals can be received at DMU 1 (102) from
sector 1 (101) as well as from Sector 2 (109) through DMU 2 (108).
These digital signals can be combined into a single digital signal
for transport to Cell 1. Thus, although the specification and
claims refer to digital signals at various stages of the
communication process, it is not required that these digital
signals are identical. One of ordinary skill in the art would
recognize many variations, modifications, and alternatives.
[0044] As illustrated in FIG. 1, the DMUs receive digital signals
from the sectors of the BBU, and then direct those digital signals
to the various DRUs. It should be noted that although embodiments
of the present invention discuss receiving a digital signal, for
example, from a BBU, and transmitting the digital signal to the
DRUs, for example, through the DMU, the digital signal that is
transmitted to the DRUs does not have to be identical to the
digital signal that is received from the BBU. As an example, as
discussed above, multiple signals from multiple sectors can be
combined at the DMU for transmission of the combined signal to the
DRUs. Additional description related to DAS are provide in U.S.
Patent Application Publication No. 2013/0114963, published on May
9, 2014, (Attorney Docket No. 91172-856309(102800US)), the
disclosure of which is hereby incorporated by reference in its
entirety for all purposes.
[0045] FIG. 2 shows an embodiment illustrating how a single BBU can
be used to provide coverage for a larger geographical area when a
frequency reuse pattern of N=1 is used. Referring to FIG. 2, cell 1
and cell 8 would share the radio resources of sector 1 (201) of the
BBU. Similarly, cell 2 and cell 10 would share the radio resources
of sector 3 (216), which are connected to DMU 214 via optical
cables 231 and 232, respectively.
[0046] The DMUs control the routing of data between the BBU and the
DRUs. Each individual data packet is provided with a header that
uniquely identifies which DRU it is associated with. The DMUs are
interconnected, for example, using optical fiber, to allow
transport of data among multiple DMUs. This feature provides the
unique flexibility in the DAS network to route signals between the
sectors of a BBU and the individual DRUs. A server 220 is utilized
to control the switching function provided in the DAS network.
[0047] Referring to FIG. 2, and by way of example, DMU 1 (202)
receives downlink signals from BBU 1 Sector 1 (201). DMU 1 collates
the baseband signals from the other DMUs onto a serial stream and
the optical fiber cable 203 transports the desired signals to DRU 2
(204) in Cell 1. Optical cable 205 transports all the optical
signals to DRU 3 (206). The other DRUs in the daisy chain are
involved in passing the optical signals onward to DRU 1 (207). DMU
1 (202) is networked with DMU 2 (208) and DMU 3 (214) to allow the
downlink signals from Sector 2 and Sector 3 to be transported to
all the DRUs in Cell 1.
[0048] Similarly for Cell 8, optical fiber cable 209 transports the
desired signals from DMU 1 (202) to DRU 23 (210). Optical cable 211
transports all the optical signals to DRU 24 (212). The other DRUs
in the daisy chain in Cell 8 are involved in passing the optical
signals onward to DRU 22 (213). Because of frequency reuse, DMU 1
(202) is able to pass signals to multiple cells in a star
configuration as illustrated in FIG. 2 via the multiple optical
cables connected to the multiple optical outputs of the DMUs.
[0049] FIG. 3 shows an embodiment illustrating an application
employing a BBU hotel where N BBUs are interconnected to serve a
given geographical area. The BBUs may represent independent
wireless network operators and/or multiple interface standards
(CPRI, OBSAI, ORI, etc.). As illustrated in FIG. 3, multiple
three-sector BBUs are connected to a daisy chained DAS network in
which each DMU utilizes multiple optical inputs and a single
optical output connected to a given cell. Thus, different operators
or different bands can be represented by the different sectors of a
BBU. Although it is not illustrated in FIG. 3 for purposes of
clarity, the DMUs can have multiple inputs as illustrated in FIG. 3
as well as multiple outputs as illustrated in FIG. 2. Accordingly,
multiple input applications in which multiple digital inputs from
different BBUs are received and multiple output applications in
which multiple digital outputs are provided at the DMU are included
within the scope of the present invention.
[0050] Referring to FIG. 3 and by way of example, DMU 1 (302)
receives downlink signals from BBU Sector 1 (301). DMU 1 (302)
transports the desired signals to DRU 2 (304). Optical cable 305
transports all the optical signals to DRU 3 (306). The other DRUs
in the daisy chain are involved in passing the optical signals
onward to DRU 1 (307). DMU 1 (302) is networked with DMU 2 (308) to
allow the downlink signals from BBU 1 Sector 2 (320) to be
transported to all the DRUs in Cell 1. DMU 1 (302) receives
downlink signals from BBU Sector N (309). DMU 1 (302) collates all
the downlink signals from the various BBUs and DMUs.
[0051] In order to efficiently utilize the limited BBU resources,
the network of DRUs should have the capability of re-directing
their individual uplink and downlink signals to and from any of the
BBU sectors. Because the DRUs data traffic has unique streams, the
DMU Router has the mechanism to route the signal to different
BBUs.
[0052] FIG. 4 shows the 2 primary elements in a DAU, the Physical
Nodes (400) and the Local Router (401). The Physical Nodes
translate the RF signals to baseband for the Downlink and from
baseband to RF for the Uplink. The Local Router directs the traffic
between the various LAN Ports, PEER Ports and the External Ports.
The physical nodes connect to the BTS at radio frequencies (RF).
The physical nodes can be used for different operators, different
frequency bands, different channels, or the like. The physical
nodes can combine the downlink and uplink signals via a duplexer or
they can keep them separate, as would be the case for a simplex
configuration. In comparison with the DMU illustrated in FIG. 8,
the physical nodes 400 are not utilized in the DMU illustrated in
FIG. 8 in some embodiments.
[0053] FIG. 4 shows an embodiment of the DAU whereby the physical
nodes have separate outputs for the uplinks (405) and separate
inputs for the downlink paths (404). The physical node translates
the signals from RF to baseband for the downlink path and from
baseband to RF for the uplink path. The physical nodes are
connected to a Local Router via external ports (409,410)). The
router directs the uplink data stream from the LAN and PEER ports
to the selected External U (uplink) ports. Similarly, the router
directs the downlink data stream from the External D (downlink)
ports to the selected LAN and PEER ports.
[0054] In one embodiment, the LAN and PEER ports are connected via
an optical fiber to a network of DMUs and DRUs. The network
connection can also use copper interconnections such as CAT 5 or 6
cabling, or other suitable interconnection equipment. The DAU is
also connected to the internet network using IP (406). An Ethernet
connection (408) is also used to communicate between the Host Unit
and the DAU. The DRU can also connect directly to the Remote
Operational Control center (407) via the Ethernet port. Additional
description related to DAUs is provided in U.S. Patent Application
Publication No. 2013/0114963, incorporated by reference above.
[0055] FIG. 5 shows the 2 primary elements in a DRU, the Physical
Nodes (501) and the Remote Router (500). The DRU includes both a
Remote Router and Physical Nodes. The Remote Router directs the
traffic between the LAN ports, External Ports and PEER Ports. The
physical nodes connect to the BTS at radio frequencies (RF). The
physical nodes can be used for different operators, different
frequency bands, different channels, etc. FIG. 5 shows an
embodiment whereby the physical nodes have separate inputs for the
uplinks (504) and separate outputs for the downlink paths (503).
The physical node translates the signals from RF to baseband for
the uplink path and from baseband to RF for the downlink path. The
physical nodes are connected to a Remote Router via external ports
(506,507). The router directs the downlink data stream from the LAN
and PEER ports to the selected External D ports. Similarly, the
router directs the uplink data stream from the External U ports to
the selected LAN and PEER ports. The DRU also contains a Ethernet
Switch (505) so that a remote computer or wireless access points
can connect to the internet. Additional description related to DRUs
is provided in U.S. Patent Application Publication No.
2013/0114963, incorporated by reference above.
[0056] FIG. 6 depicts a DAS network that includes multiple DMUs,
one or more DAUs, and multiple DRUs in an DMU and DAU network
topology. The Local Routers, illustrated by DMU A and DMU B, and
DAU L, are shown in a Daisy Chain configuration. Although a single
DAU is illustrated for purposes of clarity, additional DAUs can be
utilized in this implementation. The Remote Routers, illustrated by
portions of DRUs 601, 605, 606, 607, and 609, are shown in a star
and/or daisy chain configuration. By comparison with FIG. 5, it can
be seen that the remote router 601A and the physical node 601B are
both components of the DRU. The local routers in the DMUs and DAUs
can be interconnected via a PEER port, illustrated by optical
cables 617 and 620. The Local routers can connect to the remote
routers in the DRUs via an optical, copper, or other suitable
connection. The remote routers in the DRUs can be connected in a
daisy chain configuration with other DRUs or they may be connected
with a local router via a star configuration. The PEER ports in a
DMU are used when there is no direct connection between a physical
node connected to a local router (e.g., DMU) and a physical node
connected to a remote router (e.g., DRU). PEER ports at the DRU are
used for daisy chaining between two or more DRUs. DMUs 600/604
receive digital signals from BBU networks 631/633 via optical
cables 630/632. DMU 600 is connected to DRU 601 via optical cable
615 and 616. DRU 605 is connected to DRU 605 via optical cables
619A and 619B. DMU 604 is connected to DRUs 606 and 607 in a star
configuration using optical cables 618 and 621. DAU 608 is
connected to DRU 609 via optical cable 622.
[0057] FIG. 7 shows an embodiment illustrating an application
employing a base station/base band unit hotel where multiple BTSs
and BBUs can be interconnected to serve a given geographical area.
As will be evident to one of skill in the art, FIGS. 6 and 7
provide illustrations of related network topologies in which
digital signals are received by DMUs 600/604 from BBUs via optical
cables and RF signals are received by DAU(s) 608 from BTS(s) via RF
cables. In the embodiment illustrated in FIG. 7, one or more
three-sector BTSs and one or more three-sector BBUs can be
connected to a Daisy Chained DAS network. The BBUs may represent
independent wireless network operators, multiple bands, and/or
multiple interface standards (CPRI, OBSAI, ORI, etc.). The BTSs may
represent independent wireless network operators and interface with
DAUs at RF. Referring to FIG. 7 and by way of example, DAU 1 (702)
receives downlink signals from BTS N Sector 1 (709) via RF cable
711. DAU 1 (702) transports the desired signals to DRU 2 (704) via
optical cable 703. Optical cable 705 transports all the optical
signals to DRU 3 (706). The other DRUs in the daisy chain are
involved in passing the optical signals onward to DRU 1 (707). DAU
1 (702) is networked with DAU 2 (708) to allow the downlink signals
from BTS N Sector 2 to be transported to all the DRUs in Cell 1.
DAU 2 (708) receives downlink signals from BTS Sector N (709) via
DAU 1 as well as from BTS Sector 2 (931) via RF cable 732.
[0058] DMU 1 (712) interfaces to BBU 1 sector 1 (701). DMU 1 is
interconnected with DAU 3 743 via optical cable 741. The networking
of the DAUs to the DMUs provides a mechanism to collate signals
from BTSs with signals from BBUs. Accordingly, analog RF signals
from the BTS(s) and digital optical signals from the BBU(s) can be
routed to desired DRUs using the topology illustrated in FIG.
7.
[0059] As illustrated in FIG. 7, analog signals from BTSs and
digital signals from BBUs can be received by the DAS network by
using DAUs and DMUs, respectively. Accordingly, the DAS system
provided by embodiments of the present invention can be considered
as input signal agnostic, since it can receive digital inputs from
the BBU networks as well as analog RF inputs from the BTS and then
communicate those signals through the system to the remote
antennas. Of course, in the uplink path, the system can receive
inputs at the remote antennas and then communicate those signals in
either digital or analog format to the BBUs or DAUs.
[0060] FIG. 8 shows a block diagram of a Digital Multiplexer Unit
(DMU). The DMU 800 includes both a Router and BBU interface nodes.
The Router directs the traffic between the LAN ports, BBU Ports and
PEER Ports. The BBU nodes can be used for different operator BBU
equipment. The router directs the uplink data stream from the LAN
and PEER ports to the selected BBU ports. Similarly, the router
directs the downlink data stream from the BBU ports to the selected
LAN and PEER ports. The BBU port translates the uplink signals
destined for its specific port to the interface standard used by
the BBU connected to that specific port. Similarly, the downlink
signal from a BBU port is translated from the specific BBU protocol
standard to a common baseband signal used to collate the various
downlink signals. The DMU also contains an Ethernet port (802) so
that a remote computer or wireless access points can connect to the
internet. The LAN ports of the DMU interface to the various DRUs
connected to the DMU. The PEER ports are used to interface to other
DMUs or DAUs.
[0061] The DMU differs from a DAU in several respects. For a DAU,
the interface to the base station is via RF, that is, analog RF
signals being received at the DAU. Since the base station includes
two entities: a base band unit (BBU), which performs digital
baseband signal processing, and an RF unit, which can also be
referred to as a radio unit. In systems using a DAU, the BBU passes
the digital signal to the RF unit, which upconverts the signal to
RF and provides the signal to the DAU, which then converts the RF
signal to a digital signal. Embodiments of the present invention,
use the DMU to receive the digital signal from the BBU, removing
the process of digital to RF conversion followed by RF to digital
conversion. Thus, embodiments use the DMU, which provides a digital
interface directly to the BBU, thereby bypassing the radio unit in
the BTS and bypassing the RF portion present in a DAU.
[0062] As discussed in relation to FIG. 1, signal processing may be
performed on the digital signals received from the BBU, for
example, at BBU port 1, before the digital signals are transmitted
to the DRUs through, for example, LAN port1. Thus, the digital
signals received at the BBU ports do not have to be identical to
the digital signals transmitted at the LAN ports. Accordingly, the
use of the term digital signals herein includes implementations in
which digital signals are received, processed by the DMU, and the
digital signals are transmitted, not requiring that the received
and transmitted digital signals are identical. One of ordinary
skill in the art would recognize many variations, modifications,
and alternatives.
[0063] Referring once again to FIG. 8, inputs 808 are digital
inputs from the BBU network and outputs 803 are digital outputs to
the DRUs. In addition to signals from the BBU network, the DMU 800
also is able to receive IP traffic from the internet 805 or other
source of IP data. Accordingly, both cellular traffic from the BBU
network and IP traffic from the internet can move both upstream and
downstream through the DMU as illustrated in FIG. 8.
[0064] FIG. 9 is a simplified flowchart illustrating a method of
routing signals in a DAS according to an embodiment of the present
invention. The DAS includes a plurality of Digital Multiplexer
Units (DMUs) and a plurality of Digital Remote Units (DRUs). The
method includes receiving, at ports of the plurality of DMUs,
digital signals from sector ports of corresponding Base Band Units
(BBUs). The ports of the DMU are input/output ports that send and
receive digital signals, which may be digital optical signals. The
sector ports of the BBUs are associated with sectors of the BBU and
are also input/output ports that send and receive digital signals,
which may be digital optical signals.
[0065] The method also includes routing the digital signals between
the plurality of DMUs. As illustrated herein, the DMUs are coupled
to each other, for example, at PEER ports, using optical fiber,
enabling communication between the DMUs. Routing of the digital
signals between the plurality of DMUs can include collating a first
digital signal received from a first BBU and a second digital
signal received from a second BBU. The digital signals, which can,
for example, be associated with Sector 1 of the first BBU and
Sector 1 of the second BBU, can then be routed as a combined
signal. In this embodiment, the collated digital signal is directed
to one of the plurality of DRUs, where the signals can be processed
and broadcast using the remote antennas.
[0066] The method includes transporting the digital signals between
the plurality of DMUs and a plurality of DRUs. The coupling of the
DMUs and the DRUs, for example, using optical fiber, enables the
digital signals received from the BBUs to be transported to the
DRUs and for signals received at the DRUs to be transported to the
BBUs.
[0067] In some embodiments, routing the digital signals between the
DMUs comprises using routing tables. These routing tables can be
stored or otherwise provided at a server coupled to the plurality
of DMUs. In another implementation, the routing tables are stored
or otherwise provided at one or more of the DRUs. In still another
implementation, the routing tables, for example, for each DMU
and/or each DRU are stored in the cloud. The routing tables can
include Merge Blocks that facilitate merging of signals received at
multiple DRUs. In an embodiment, a power level of each carrier in
each DRU is independently controlled, improving system
performance.
[0068] It should be appreciated that the specific steps illustrated
in FIG. 9 provide a particular method of routing signals in a DAS
according to an embodiment of the present invention. Other
sequences of steps may also be performed according to alternative
embodiments. For example, alternative embodiments of the present
invention may perform the steps outlined above in a different
order. Moreover, the individual steps illustrated in FIG. 9 may
include multiple sub-steps that may be performed in various
sequences as appropriate to the individual step. Furthermore,
additional steps may be added or removed depending on the
particular applications. One of ordinary skill in the art would
recognize many variations, modifications, and alternatives.
[0069] In some embodiments of the present invention, router tables
are used to configure the networked DAUs. The local router tables
establish the mapping of the inputs to the various outputs.
Internal Merge blocks are utilized for the Downlink Tables when the
inputs from an External Port and a PEER Port need to merge into the
same data stream. Similarly, Merge blocks are used in the Uplink
Tables when the inputs from the LAN Ports and PEER Ports need to
merge into the same data stream.
[0070] The remote router tables establish the mapping of the inputs
to the various outputs. Internal Merge blocks are utilized for the
Downlink Tables when the inputs from a LAN Port and a PEER Port
need to merge into the same data stream. Similarly, Merge blocks
are used in the Uplink Tables when the inputs from the External
Ports and PEER Ports need to merge into the same data stream.
Additional description related to router tables is provided in U.S.
Patent Application Publication No. 2013/0114963, incorporated by
reference above.
[0071] As an example, the amount of radio resources (such as RF
carriers, the power level of each carrier, LTE Resource Blocks,
CDMA codes or TDMA time slots) assigned to a particular DMU/DRU or
group of DMUs/DRUs can be set via software control to meet desired
capacity and throughput objectives or wireless subscriber needs.
Applications of the present invention are suitable to be employed
with distributed base stations, distributed baseband units,
distributed antenna systems, distributed repeaters, mobile
equipment and wireless terminals, portable wireless devices, and
other wireless communication systems such as microwave and
satellite communications.
[0072] FIG. 10 is a schematic block diagram of a Radio Access
Network (RAN) 1000 according to an embodiment of the present
invention. The RAN 1000 provides connection between the Core
Network 1010, in this case, such as an Evolved Packet Core (EPC)
network, and user equipment including cellular devices, public
safety equipment and Wi-Fi equipment. The Core Network 1010 is
connected to a base transceiver station (BTS)/baseband unit (BBU)
pool 1020 by Gigabit Ethernet (GbE) backhaul transport, for
example, using CAT6/7 cables. The BTS/BBU pool 1020 may include one
or more base transceiver stations (BTSs) 1022 and one or more
baseband units (BBUs) 1024.
[0073] The BTS(s) 1022 and BBU(s) 1024 are in bidirectional
communication with one or more universal base station interface
trays (UBiTs) 1030, which aggregate and transport base station
resources to remote units (e.g., DRUs 1040, 1042, 1044, etc.). The
UbiT 1030 is multi-operator, multi-band/channel and multi-standard,
and provides an RF and fronthaul interface for packetized data
(e.g., CPRI data, ORI data, etc.). In some embodiments, the
fronthaul interface of the UbiT 1030 may be included on a single
chip. In some embodiments, the fronthaul interface may be included
on one board or multiple boards as a rack mounted unit. The UbiT
1030 implements an open application programming interface (API) as
its data interface. In one embodiment, the UbiT 1030 provides up to
and above 10 Gbps per wavelength digital transport. The UbiT 1030
includes one or more RF conditioners (RFCs), a host unit, and a
baseband interface (BBI). The BBI can be a digital multiplexer as
described herein.
[0074] The digital remote units (DRUs 1040, 1042, 1044) can be in
communication with indoor or outdoor antennas, WiFi access points
(APs), and/or IP/IoT device(s) or application(s), providing support
for cellular service, the public safety band and WiFi. In one
embodiment, the WiFi APs and/or IP/IoT device(s) can receive IP
traffic from the DRUs. Thus, IP traffic can be routed between the
DMUs and the DRUs along with the I/Q data. The DRUs can be software
configurable, and be mid power (e.g., +30 dBm/ch, +37 dBm/ch,
etc.), or high power (e.g., +43 dBm/ch, +46 dBm/ch, etc.). They can
provide channelized processing, capacity routing on demand and IP
backhaul (e.g., 1 Gbps, 10 Gbps, etc.). The DRUs can be, for
example, any type of remote unit, such as those described
herein.
[0075] The BTS/BBU pool 1020, the UbiT, and the DRUs 1040, 1042,
1044 may be part of an access network 1015 that may be located at
one or more locations remote from core network 1010.
[0076] FIG. 11 is a schematic block diagram of a Centralized Radio
Access Network (C-RAN) 1100 according to an embodiment of the
present invention. The C-RAN 1100 provides connection between the
Core Network 1110, such as an EPC network, and user equipment
including cellular devices, public safety equipment and WiFi
equipment. The Core Network 1110 is connected to a BBU pool 1120 by
GbE backhaul transport, for example, using CAT 6/7 cables. The BBU
pool 1120 may include one or more baseband units (BBUs) 1122,
1124.
[0077] The BBU pool 1120 is in communication with one or more
fronthaul interfaces 1130. The fronthaul interfaces 1130 may
include any packetized approaches and/or transport protocols for
switching (e.g., routing input ports to output ports) and/or
routing (e.g., using a source and destination address scheme).
Exemplary fronthaul interfaces 1130 may include switches and/or
routers for use with CPRI, ORI, Ethernet, CPRI over Ethernet, and
the like. In some embodiments, the fronthaul interfaces 1130 may
each be included on a single chip. In some embodiments, the
fronthaul interfaces 1130 may be included on one board or multiple
boards as a rack mounted unit. The fronthaul interfaces 1130 use
DMUs 1132, 1134 to implement packet-based switching and route
packets (e.g., payload I/Q data, Control & Management data,
header information, IP traffic, etc.). The fronthaul interfaces
1130 communicate directly with various locations, as well as with a
further DMU 1142 at another location using the interface standard
at 10, 40 or 100 Gbps, for example. The BBU pool 1120 and the
fronthaul interface 1130 may together form a central office 1115.
The central office 1115 may be located remotely from the core
network 1110 in some embodiments.
[0078] The DMUs 1132, 1134, 1142 implement open APIs based on a
packetized protocol in one embodiment and provide, for example, an
up to and above 10 Gbps per wavelength interface. The DMUs 1132,
1134, 1142 provide integrated wavelength division multiplexing
(WDM) for, for example, 40 Gbps and 100 Gbps. The DMU 1142
interfaces with one or more DRUs (e.g., DRUs 1152, 1154, 1156,
1162, 1164, 1166). The DMU 1142 and the DRUs 1152, 1154, 1156,
1162, 1164, 1166 may be part of an access network 1140 located at
one or more locations remote from the core network 1110 and or the
central office 1115.
[0079] The fronthaul interfaces 1130 can include any of the DMUs
described herein. The DMUs 1132, 1134, 1142 have a forwarding plane
and a control plane. The forwarding plane includes the routing
paths through the DMU which are configured by the C&M (Control
and Management). In some embodiments, the C&M configuration is
located in the cloud as described further herein, although these
functions can alternatively be configured in a server, as described
further herein. The C&M establishes the routing paths between
the inputs and outputs of each DMU.
[0080] The DMUs 1132, 1134 may be configured to receive a plurality
of signals from one or more BBUs 1122, 1124. The DMUs 1132, 1134
may extract a subset of the plurality of signals intended for a
particular DRU 1152, 1154, 1156, 1162, 1164, 1166, as specified by
C&M information, as described further herein. The DMUs 1132,
1134 may aggregate the subset of the plurality of signals into a
stream, and route the stream to one or more DRUs 1152, 1154, 1156,
1162, 1164, 1166. The stream can be routed to the one or more DRUs
1152, 1154, 1156, 1162, 1164, 1166 via the DMU 1142. In some
embodiments, the DMU 1142 may decompose the stream, e.g., back into
the subset of signals, before routing it to the one or more DRUs
1152, 1154, 1156, 1162, 1164, 1166. As shown in FIG. 11, the DMU
1142 may be collocated with the DRUs 1152, 1154, 1156, 1162, 1164,
1166, for example, at a location remote from the DMUs 1132,
1134.
[0081] In one embodiment, the DMU 1142 can be eliminated. In other
words, the DMUs 1132, 1134 may route the stream directly to the one
or more DRUs 1152, 1154, 1156, 1162, 1164, 1166. In this
embodiment, the fronthaul interfaces 1130 can communicate directly
with a DRU. This DRU can be daisy chained or deployed in a star
configuration with one or more additional DRUs.
[0082] The DRUs 1152, 1154, 1156, 1162, 1164, 1166 can be in
communication with IP/IoT device(s) or application(s), and can
provide support for cellular service, the public safety band and
WiFi. In one embodiment, the WiFi APs and/or IP/IoT device(s) can
receive IP traffic from the RUs. Accordingly, WiFi APs, in addition
to other IoT devices can receive IP traffic. The DRUs 1152, 1154,
1156, 1162, 1164, 1166 can be software configurable, and be low
power (e.g., +18 dBm/ch, +23 dBm/ch, etc.), mid power (e.g., +30
dBm/ch, +37 dBm/ch, etc.), or high power (e.g., +43 dBm/ch, +46
dBm/ch, etc.). They can provide channelized processing, capacity
routing on demand and IP backhaul (e.g., 1 Gbps, 10 Gbps, higher
bandwidths, etc.). The low power DRUs (e.g., hd18-4) are wideband
or narrowband (e.g., cover a frequency range from 150 MHz to 70
GHz), have an instantaneous bandwidth, for example, of up to and
above 100 MHz, have agile channel positioning, are single, quad- or
octo-band/channel, have integrated antennas and WiFi APs and
provide IP backhaul. The mid power (e.g., hd30-4) and high power
(e.g., hd43-4) DRUs are narrowband, quad band RUs that can be in
communication with indoor or outdoor antennas and WiFi APs, and can
have an instantaneous bandwidth, for example, up to and above 100
MHz. The DRUs 1152, 1154, 1156, 1162, 1164, 1166 can be, for
example, any type of remote unit, such as those described
herein.
[0083] FIG. 12 is a schematic block diagram illustrating a
multi-operator C-RAN 1200 according to an embodiment of the present
invention. The C-RAN 1200 provides connection between the Core
Networks 1202, 1204, 1206, such as EPC networks, and user equipment
including cellular devices, public safety equipment and WiFi
equipment. The Core Network 1202 is connected to a Central Office
Operator 1210 that operates a BBU pool 1212 and a front haul
interface 1215. The Core Network 1202 may be connected to the BBU
pool 1212 of the Central Office Operator 1210 by GbE backhaul
transport, for example, using CAT 6/7 cables. The BBU pool 1212 may
include one or more baseband units (BBUs) 1213, 1214.
[0084] The Core Network 1204 is connected to another Central Office
Operator 1220 that operates a BBU pool 1222 and a fronthaul
interface 1225. The Core Network 1202 may be connected to the BBU
pool 1222 of the Central Office Operator 1220 by GbE backhaul
transport, for example, using CAT 6/7 cables. The BBU pool 1222 may
include one or more baseband units (BBUs) 1223, 1224.
[0085] The Core Network 1206 is connected to another Central Office
Operator 1230 that operates a BBU pool 1232 and a fronthaul
interface 1235. The Core Network 1202 may be connected to the BBU
pool 1232 of the Central Office Operator 1230 by GbE backhaul
transport, for example, using CAT 6/7 cables. The BBU pool 1232 may
include one or more baseband units (BBUs) 1233, 1234.
[0086] In other words, each Central Office Operator 1210, 1220,
1230 has a respective BBU pool and fronthaul interface, as well as
a backhaul to a Core Network 1202, 1204, 1206, respectively.
Although shown and described as comprising three Core Networks
1202, 1204, 1206 connected to three Central Office Operators 1210,
1220, 1230, it is contemplated that any number of Core Networks and
Central Office Operators may be implemented in accordance with
embodiments of the invention. The Central Office Operators 1210,
1220, 1230 may be located remotely from the Core Networks 1202,
1204, 1206, respectively, in some embodiments.
[0087] Each of the BBU pools 1212, 1222, 1232 is in communication
with one or more fronthaul interfaces 1215, 1225, 1235,
respectively. The fronthaul interfaces 1215, 1225, 1235 may include
any packetized approaches and/or transport protocols for switching
(e.g., routing input ports to output ports) and/or routing (e.g.,
using a source and destination address scheme). Exemplary fronthaul
interfaces 1215, 1225, 1235 may include switches and/or routers for
use with CPRI, ORI, Ethernet, CPRI over Ethernet, and the like. In
some embodiments, the fronthaul interfaces 1215, 1225, 1235 may
each be included on a single chip. In some embodiments, the
fronthaul interfaces 1215, 1225, 1235 may be included on one board
or multiple boards as a rack mounted unit. The fronthaul interfaces
1215, 1225, 1235 use DMUs (e.g., DMUs 1216, 1217, 1226, 1227, 1236,
1237) to implement packet-based switching and route CPRI packets
(payload I/Q data, Control & Management data, header
information, IP traffic, etc.). The fronthaul interfaces 1215,
1225, 1235 communicate directly with various locations, as well as
with a further DMU 1242 at another location using the interface
standard at 10, 40 or 100 Gbps, for example.
[0088] The DMUs 1216, 1217, 1226, 1227, 1236, 1237, 1242 implement
open APIs based on a packetized protocol in one embodiment and
provide, for example, an up to and above 10 Gbps per wavelength
interface. The DMUs 1216, 1217, 1226, 1227, 1236, 1237, 1242
provide integrated wavelength division multiplexing (WDM) for, for
example, 40 Gbps and 100 Gbps. The DMU 1242 interfaces with one or
more DRUs (e.g., DRUs 1252, 1254, 1256, 1262, 1264, 1266). The DMU
1242 and the DRUs 1252, 1254, 1256, 1262, 1264, 1266 may be part of
an access network 1240 located at one or more locations remote from
the Core Networks 1202, 1204, 1206 and/or the Central Office
Operators 1210, 1220, 1230. In this embodiment, the DMU 1242 is
capable of aggregating content from multiple different Central
Office Operators 1210, 1220, 1230 and sending the aggregated
content to one or more DRUs 1252, 1254, 1256, 1262, 1264, 1266,
which are operator agnostic. In other words, the embodiment shown
and described with respect to FIG. 11 relates to a single operator
C-RAN, while the embodiment shown and described with respect to
FIG. 12 relates to a multi-operator C-RAN.
[0089] The fronthaul interfaces 1215, 1225, 1235 can include any of
the DMUs described herein. The DMUs 1216, 1217, 1226, 1227, 1236,
1237, 1242 have a forwarding plane and a control plane. The
forwarding plane includes the routing paths through the DMU which
are configured by the C&M (Control and Management). In some
embodiments, the C&M configuration is located in the cloud as
described further herein, although these functions can
alternatively be configured in a server, as described further
herein. The C&M establishes the routing paths between the
inputs and outputs of each DMU.
[0090] The DMUs 1216, 1217, 1226, 1227, 1236, 1237 may be
configured to receive a plurality of signals from one or more BBUs
1213, 1214, 1223, 1224, 1233, 1234. The DMUs 1216, 1217, 1226,
1227, 1236, 1237 may extract a subset of the plurality of signals
intended for a particular DRU 1252, 1254, 1256, 1262, 1264, 1266,
as specified by C&M information, as described further herein.
The DMUs 1216, 1217, 1226, 1227, 1236, 1237 may aggregate the
subset of the plurality of signals into a stream, and route the
stream to one or more DRUs 1252, 1254, 1256, 1262, 1264, 1266. The
stream can be routed to the one or more DRUs 1252, 1254, 1256,
1262, 1264, 1266 via the DMU 1242. In some embodiments, the DMU
1242 may decompose the stream, e.g., back into the subset of
signals, before routing it to the one or more DRUs 1252, 1254,
1256, 1262, 1264, 1266. As shown in FIG. 12, the DMU 1242 may be
collocated with the DRUs 1252, 1254, 1256, 1262, 1264, 1266 via the
DMU 1242, for example, at a location remote from the DMUs 1216,
1217, 1226, 1227, 1236, 1237.
[0091] In one embodiment, the DMU 1242 can be eliminated. In other
words, the DMUs 1216, 1217, 1226, 1227, 1236, 1237 may route the
stream directly to the one or more DRUs 1252, 1254, 1256, 1262,
1264, 1266. In this embodiment, the fronthaul interfaces 1215,
1225, 1235 can communicate directly with a DRU. This DRU can be
daisy chained or deployed in a star configuration with one or more
additional DRUs.
[0092] The DRUs 1252, 1254, 1256, 1262, 1264, 1266 can be in
communication with IP/IoT device(s) or application(s), and can
provide support for cellular service, the public safety band and
WiFi. In one embodiment, the WiFi APs and/or IP/IoT device(s) can
receive IP traffic from the RUs. Accordingly, WiFi APs, in addition
to other IoT devices can receive IP traffic. The DRUs 1252, 1254,
1256, 1262, 1264, 1266 can be software configurable, and be low
power (e.g., +18 dBm/ch, +23 dBm/ch, etc.), mid power (e.g., +30
dBm/ch, +37 dBm/ch, etc.), or high power (e.g., +43 dBm/ch, +46
dBm/ch, etc.). They can provide channelized processing, capacity
routing on demand and IP backhaul (e.g., 1 Gbps, 10 Gbps, higher
bandwidths, etc.). The low power DRUs (e.g., hd18-4) are wideband
or narrowband (e.g., cover a frequency range of 150 MHz to 70 GHz),
have an instantaneous bandwidth, for example, of up to and above
100 MHz, have agile channel positioning, are single, quad- or
octo-band/channel, have integrated antennas and WiFi APs and
provide IP backhaul. The mid power (e.g., hd30-4) and high power
(e.g., hd43-4) DRUs are narrowband, quad band RUs that can be in
communication with indoor or outdoor antennas and WiFi APs, and can
have an instantaneous bandwidth, for example, up to and above 100
MHz. The DRUs 1252, 1254, 1256, 1262, 1264, 1266 can be, for
example, any type of remote unit, such as those described
herein.
[0093] FIG. 13 is a schematic block diagram of a Cloud Radio Access
Network 1300 according to an embodiment of the present invention.
The Cloud RAN 1300 provides connection between the Core Network
1310, such as an EPC network, and user equipment including cellular
devices, public safety equipment and WiFi equipment. The Core
Network 1310 is connected to a Data Center 1315 by GbE backhaul
transport, for example, using CAT 6/7 cables. The Data Center 1315
may include one or more virtual BBUs (vBBUs) 1320 and one or more
fronthaul interfaces 1340. In one embodiment, the virtual BBUs 1320
are implemented using off-the-shelf data servers. The fronthaul
interfaces 1340 can include any of the DMUs or DRUs described
herein. The DMUs 1352 (and internal to fronthaul interfaces 1340)
and DRUs 1362, 1364, 1366, 1372, 1374, 1376 have a forwarding plane
and a control plane. The forwarding plane defines the routing paths
through the DMUs and DRUs, which are configured by the C&M. The
C&M configuration is located in the cloud in one embodiment,
although these functions can alternatively be configured in a
remote server 1345. The C&M establishes the routing paths
between the inputs and outputs of each DMU and DRU.
[0094] The Data Center 1315 is implemented via a Software Defined
Network (SDN) 1330 and provides remote control and management
functionality. In other words, control of the fronthaul interfaces
1340 can be handled in the cloud. The fronthaul interfaces 1340
implement packet-based switching and route (forwarding plane)
packets between DMUs and DRUs. In some embodiments, the fronthaul
interfaces 1340 may each be included on a single chip. In some
embodiments, the fronthaul interfaces 1340 may be included on one
board or multiple boards as a rack mounted unit.
[0095] The fronthaul interfaces 1340 may include one or more DMUs
as described further herein with respect to FIGS. 11 and 12, and
may be configured to receive a plurality of signals from one or
more virtual BBUs 1320. The DMUs of the fronthaul interfaces 1340
may extract a subset of the plurality of signals intended for a
particular DRU 1362, 1364, 1366, 1372, 1374, 1376, as specified by
C&M information, as described further herein. The DMUs of the
fronthaul interfaces 1340 may aggregate the subset of the plurality
of signals into a stream, and route the stream to one or more DRUs
1362, 1364, 1366, 1372, 1374, 1376. The stream can be routed to the
one or more DRUs 1362, 1364, 1366, 1372, 1374, 1376 via the DMU
1352. In some embodiments, the DMU 1352 may decompose the stream,
e.g., back into the subset of signals, before routing it to the one
or more DRUs 1362, 1364, 1366, 1372, 1374, 1376. As shown in FIG.
12, the DMU 1352 may be collocated with the DRUs 1362, 1364, 1366,
1372, 1374, 1376 via the DMU 1352, for example, at a location
remote from the fronthaul interfaces 1340.
[0096] In one embodiment, the DMU 1352 can be eliminated. In other
words, the DMUs of the fronthaul interfaces 1340 may route the
stream directly to the one or more DRUs 1362, 1364, 1366, 1372,
1374, 1376. In this embodiment, the fronthaul interfaces 1340 can
communicate directly with a DRU. This DRU can be daisy chained or
deployed in a star configuration with one or more additional
DRUs.
[0097] The Data Center 1315 communicates directly with various
locations, as well as with a DMU 1352 at one location using the
interface standard at 10, 40 or 100 Gbps, for example. The DMU 1352
implements an open API based on a packetized protocol and provides,
for example, an up to and above 10 Gbps per wavelength interface.
The DMU 1352 provides integrated wavelength division multiplexing
(WDM) for, for example, 40 Gbps and 100 Gbps. The DMU 1352
interfaces with one or more DRUs (e.g., DRUs 1362, 1364, 1366,
1372, 1374, 1376). The DMU 1352 and the DRUs 1362, 1364, 1366,
1372, 1374, 1376 may be part of an access network 1350 that may be
located remotely at one or more locations.
[0098] The DRUs 1362, 1364, 1366, 1372, 1374, 1376 can be in
communication with IP/IoT device(s) or application(s), and can
provide support for cellular service, the public safety band and
WiFi. In one embodiment, the WiFi APs and/or IP/IoT device(s) can
receive IP traffic from the RUs. The DRUs 1362, 1364, 1366, 1372,
1374, 137 can be software configurable, and be low power (e.g., +18
dBm/ch, +23 dBm/ch, etc.), mid power (e.g., +30 dBm/ch, +37 dBm/ch,
etc.), or high power (e.g., +43 dBm/ch, +46 dBm/ch, etc.). They can
provide channelized processing, capacity routing on demand and IP
backhaul (e.g., 1 Gbps, 10 Gbps, etc.). The low power DRUs (e.g.,
hd18-4) are wideband or narrowband (e.g., cover a frequency range
from 150 MHz to 70 GHz), have an instantaneous bandwidth, for
example, of up to and above 100 MHz, have agile channel
positioning, are single or quad band/channel, have integrated
antennas and WiFi APs and provide IP backhaul. The mid power (e.g.,
hd30-4) and high power (e.g., hd43-4) DRUs are narrowband, quad
band DRUs that can be in communication with indoor or outdoor
antennas and WiFi APs, and can have an instantaneous bandwidth, for
example, up to and above 100 MHz. The DRUs 1362, 1364, 1366, 1372,
1374, 1376 can be, for example, any type of remote unit, such as
those described herein.
[0099] As compared with other embodiments and conventional RANs,
the embodiment shown in FIG. 13 has a substantially reduced amount
of equipment utilized for deployment. For example, the
implementation shown in FIG. 13 does not necessarily require UBiTs
and RFCs.
[0100] FIG. 14 is a simplified flowchart 1400 illustrating a method
of control and management (C&M) of the RAN according to an
embodiment of the present invention. In some embodiments, some or
all of the C&M functionality illustrated by flowchart 1400 may
be implemented in a cloud network, as described further herein. At
step 1410, signals are defined at a DMU. Although described as
occurring "at a DMU", it is contemplated that the signals can be
defined on a cloud (e.g., by an application over the Internet), by
a remote server, and/or by plugging directly into the DMU.
[0101] FIG. 15 is a screen shot of an exemplary user interface 1500
for defining signals in one implementation of step 1410 of FIG. 14.
As shown in FIG. 15, a DMU is selected ("O1_HostQS-Cw01"). The DMU
selected in FIG. 15 is a quad-band unit defined by bands of 700
MHz, 850 MHz, 1900 MHz and AWS. Signals may be defined by their
center frequency, bandwidth, start frequency-stop frequency, a
table, a graphic, and/or the like. In FIG. 15, a table is selected
that is pre-populated with bands defined by regulatory bodies
(e.g., "700-A 698-704/728-734 MHz"). The signals may also be
defined by assigning names (e.g., "ATT-700-B-S1").
[0102] In some embodiments, at step 1410 of FIG. 14, a check is
made to ensure that the number of defined signals is less than or
equal to a maximum number of signals that that DMU can process. If
the number of defined signals exceeds the maximum number of
signals, the user requesting definition of the signals may be
informed.
[0103] Once the signals are defined, the signals can be allocated
to specific DRUs. At step 1412 of FIG. 14, signals are selected for
each DRU. It is contemplated that the signals can be allocated on a
cloud (e.g., by an application over the Internet), by a remote
server, and/or by plugging directly into one or more DRUs.
[0104] FIG. 16 is a screen shot of an exemplary user interface 1600
for selecting signals in one implementation of step 1412 of FIG.
14. As shown in FIG. 16, a DRU is selected ("hd30-11"). The DRU
selected in FIG. 16 is a quad-band unit defined by bands of 700
MHz, 850 MHz, 1900 MHz and AWS. Drop-down boxes allow a user to
select signals according to their name assigned in step 1410 (e.g.,
"ATT-700-A-S1"), from the pool of all signals defined in step 1410.
By selecting a particular signal name, the signal corresponding to
that signal name will be processed on that particular DRU.
[0105] In some embodiments, at step 1412 of FIG. 14, a check may be
made to ensure that the number of selected signals is less than or
equal to a maximum number of signals that that DRU can process. If
the number of selected signals exceeds the maximum number of
signals, the user requesting selection of the signals may be
informed. In some embodiments, at step 1412 of FIG. 14, a check may
be made to ensure that the total bandwidth of the selected signals
for the cluster of DRUs fed from the DMU of step 1410 is less than
or equal to the maximum bandwidth of signals that can be
transported over the optical link between the DMU and the DRUs. If
the total bandwidth exceeds the maximum bandwidth, the user
requesting selection of the signals may be informed.
[0106] Once the signals are selected for one or more DRUs, serial
data streams can be created. At step 1414 of FIG. 14, data streams
are formed for each DRU or cluster of DRUs based on the selected
signals at the DMU. Although described as occurring "at a DMU", it
is contemplated that the signals can be defined on a cloud (e.g.,
by an application over the Internet), by a remote server, and/or by
plugging directly into the DMU. Thus, the selected signals may be
routed from the DMU to the one or more DRUs specified at step
1412.
[0107] FIG. 17 is an overall schematic block diagram of a Cloud RAN
according to an embodiment of the invention. A Core Network 1710
communicates via GbE backhaul transport with a Data Center 1715
(comprising virtual BBUs 1717), a Local Data Center 1720
(comprising virtual BBUs 1722, fronthaul interfaces 1726, and an
SDN 1724), and a Mega Data Center 1730 (comprising virtual BBUs
1732, fronthaul interfaces 1736, and an SDN 1734). The Data Center
1715, Local Data Center 1720 and Mega Data Center 1730 use
packetized fronthaul transport to provide outdoor and indoor DAS
coverage at a variety of locations 1740, 1752, 1754, 1756, 1760.
The Cloud RAN shown in FIG. 17 can be implemented using the
components illustrated with respect to FIG. 13, for example.
[0108] It is understood that the examples and embodiments described
herein are for illustrative purposes only and that various
modifications or changes in light thereof will be suggested to
persons skilled in the art and are to be included within the spirit
and purview of this application and scope of the appended
claims.
[0109] Appendix I is a glossary of terms used herein, including
acronyms.
APPENDIX I
Glossary of Terms
[0110] ACLR Adjacent Channel Leakage Ratio [0111] ACPR Adjacent
Channel Power Ratio [0112] ADC Analog to Digital Converter [0113]
AQDM Analog Quadrature Demodulator [0114] AQM Analog Quadrature
Modulator [0115] AQDMC Analog Quadrature Demodulator Corrector
[0116] AQMC Analog Quadrature Modulator Corrector [0117] BPF
Bandpass Filter [0118] CDMA Code Division Multiple Access [0119]
CFR Crest Factor Reduction [0120] DAC Digital to Analog Converter
[0121] DET Detector [0122] DHMPA Digital Hybrid Mode Power
Amplifier [0123] DDC Digital Down Converter [0124] DNC Down
Converter [0125] DPA Doherty Power Amplifier [0126] DQDM Digital
Quadrature Demodulator [0127] DQM Digital Quadrature Modulator
[0128] DSP Digital Signal Processing [0129] DUC Digital Up
Converter [0130] EER Envelope Elimination and Restoration [0131] EF
Envelope Following [0132] ET Envelope Tracking [0133] EVM Error
Vector Magnitude [0134] FFLPA Feedforward Linear Power Amplifier
[0135] FIR Finite Impulse Response [0136] FPGA Field-Programmable
Gate Array [0137] GSM Global System for Mobile communications
[0138] I-Q In-phase/Quadrature [0139] IF Intermediate Frequency
[0140] LINC Linear Amplification using Nonlinear Components [0141]
LO Local Oscillator [0142] LPF Low Pass Filter [0143] MCPA
Multi-Carrier Power Amplifier [0144] MDS Multi-Directional Search
[0145] OFDM Orthogonal Frequency Division Multiplexing [0146] PA
Power Amplifier [0147] PAPR Peak-to-Average Power Ratio [0148] PD
Digital Baseband Predistortion [0149] PLL Phase Locked Loop [0150]
QAM Quadrature Amplitude Modulation [0151] QPSK Quadrature Phase
Shift Keying [0152] RF Radio Frequency [0153] RRH Remote Radio Head
[0154] RRU Remote Radio Head Unit [0155] SAW Surface Acoustic Wave
Filter [0156] UMTS Universal Mobile Telecommunications System
[0157] UPC Up Converter [0158] WCDMA Wideband Code Division
Multiple Access [0159] WLAN Wireless Local Area Network
* * * * *