U.S. patent application number 12/477098 was filed with the patent office on 2009-09-24 for electrical ring distribution interface for an optical transceiver.
Invention is credited to Glen Miller, Armin Schulz, Timothy P. Walker.
Application Number | 20090238567 12/477098 |
Document ID | / |
Family ID | 38559083 |
Filed Date | 2009-09-24 |
United States Patent
Application |
20090238567 |
Kind Code |
A1 |
Miller; Glen ; et
al. |
September 24, 2009 |
Electrical Ring Distribution Interface for an Optical
Transceiver
Abstract
A ring connection system and method are provided for
distributing signals in an optical-to-electrical interface. The
method electrically connects a plurality of nodes in a
series-connected ring, and receives an optical signal at a first
node from a service provider. The method converts the optical
signal to an electrical signal, and distributes the electrical
signal via the ring. At each node, the electrical signal is
supplied from a customer interface. Typically, each node has a
plurality of customer interfaces. In one aspect, ITU-T G.984.3
Giagbit-capable Passive Optical Network (GPON) optical signals are
received converted to a customer interface electrical signal such
as an Ethernet, asynchronous transfer mode, or time division
multiplexed signal. Electrically connecting the plurality of nodes
in the series-connected ring includes: series connecting the nodes
in a North ring; and, series connecting the nodes in a South ring,
opposite in direction from the North ring.
Inventors: |
Miller; Glen; (Haverhill,
MA) ; Schulz; Armin; (Methuen, MA) ; Walker;
Timothy P.; (Boxford, MA) |
Correspondence
Address: |
Gerald W. Maliszewski
P.O. Box 270829
San Diego
CA
92198-2829
US
|
Family ID: |
38559083 |
Appl. No.: |
12/477098 |
Filed: |
June 2, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11395858 |
Mar 31, 2006 |
7561801 |
|
|
12477098 |
|
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Current U.S.
Class: |
398/59 |
Current CPC
Class: |
H04Q 11/0067 20130101;
H04L 12/42 20130101; H04Q 2011/0092 20130101; H04B 10/27 20130101;
H04Q 11/0071 20130101; H04L 12/2854 20130101; H04L 12/437
20130101 |
Class at
Publication: |
398/59 |
International
Class: |
H04B 10/20 20060101
H04B010/20 |
Claims
1. In an optical-to-electrical interface, a ring connection method
for distributing signals, the method comprising: electrically
connecting a plurality of nodes in a series-connected ring;
receiving an optical signal at a first node from a service
provider; converting the optical signal to an electrical signal;
distributing the electrical signal via the ring; and, at each node,
supplying the electrical signal from a customer interface.
2. The method of claim 1 wherein electrically connecting the
plurality of nodes in the series-connected ring includes: series
connecting the nodes in a first (North) ring; and, series
connecting the nodes in a second (South) ring, opposite in
direction from the first ring.
3. The method of claim 1 wherein converting the optical signal to
the electrical signal includes converting an encrypted optical
signal into an encrypted electrical signal; and, wherein supplying
the electrical signal from the customer interface includes
selectively decrypting the encrypted electrical signal at each
node.
4. The method of claim 1 further comprising: accepting a first
(Working) optical signal at the first node; and, accepting a second
(Protection) optical signal at a second node; and, wherein
receiving the optical signal from the service provider includes:
initially converting the first optical signal to an electrical
signal; and, in the event of an optical line fault, converting the
second optical signal to the electrical signal.
5. The method of claim 1 wherein receiving the optical signal from
the service provider includes receiving a ITU-T G.984.3
Giagbit-capable Passive Optical Network (GPON) signal; and, wherein
converting the optical signal to the electrical signal includes
converting to a customer interface electrical signal selected from
a group consisting of Ethernet, asynchronous transfer mode (ATM),
and time division multiplexing (TDM).
6. The method of claim 5 wherein supplying the electrical signal
from the customer interface includes supplying a plurality of
customer interface electrical signals from a corresponding
plurality of customer interface ports at each node.
7. The method of claim 6 wherein supplying the plurality of
customer interface electrical signals from the corresponding
plurality of customer interface ports at each node includes time
division demultiplexing the GPON signal into the plurality of
customer interface electrical signals.
8. The method of claim 7 wherein supplying the plurality of
customer interface electrical signals from the corresponding
plurality of customer interface ports at each node includes:
multiplexing customer interface electrical signals supplied from
ring-connected nodes; and, supplying a multiplexed customer
interface electrical signal to a customer interface.
9. The method of claim 1 further comprising: at each node,
receiving a customer interface electrical signal from a customer
interface; multiplexing the received customer interface electrical
signals from each node; converting the multiplexed electrical
signals into an optical signal; and, transmitting the optical
signal to the service provider.
10. The method of claim 9 further comprising: distributing the
multiplexed electrical signals via the ring.
11. The method of claim 9 wherein receiving the electrical signal
from the customer interface at each node includes: accepting a
plurality of customer interface electrical signals from a plurality
of customer interfaces; and, framing the plurality of customer
interface electrical signals into a GPON signal.
12. A ring-connected optical network unit (ON-U) for distributing
signals, the ONU comprising: an optical port for transceiving
optical signals; an optical-to-electrical translation module having
an interface connected to the optical port, and an interface for
transceiving electrical signals; a first (North) ring port
connected to the translation module for the ring-connected
transceiving of electrical signals; a second (South) ring port
connected to the translation module for the ring-connected
transceiving of electrical signals; and, a customer interface port
to transceive electrical signals with a user.
13. The ONU of claim 12 wherein the translation module converts an
encrypted optical signal into an encrypted electrical signal;
wherein the first and second ring ports distribute encrypted
electrical signals; and, the ONU further comprising: a deframer
module having an interface connected to the translation module and
an interface to supply a decrypted electrical signal to the
customer interface.
14. The ONU of claim 13 wherein the translation module receives a
ITU-T G.984.3 Giagbit-capable Passive Optical Network (GPON) signal
and converts the GPON optical signal into a GPON electrical signal;
and, wherein the deframer module converts the GPON electrical
signal into a customer interface electrical signal.
15. The ONU of claim 13 further comprising: a plurality of customer
interfaces connected to the deframer module, each transceiving
customer interface electrical signals with a user.
16. The ONU of claim 15 wherein the deframer module time division
demultiplexes a GPON signal into a customer interface electrical
signal for each customer interface, where the customer interface
electrical signal is selected from a group consisting of Ethernet,
asynchronous transfer mode (ATM), and time division multiplexing
(TDM).
17. The ONU of claim 15 further comprising: a downlink multiplexer
having an interface connected to the ring ports and the translation
module to receive electrical signals, and an interface connected to
the deframer to supply a multiplexed electrical signal.
18. The ONU of claim 12 further comprising: a first multiplexer
having an interface connected to the ring ports and the customer
interface to receive electrical signals, and an interface connected
to the translation module to supply a multiplexed electrical
signal; and, wherein the translation module converts multiplexed
electrical signals into an optical signal, and transmits the
optical signal.
19. The ONU of claim 18 further comprising: a second multiplexer
having an interface connected to the ring ports and the customer
interface to receive electrical signals, and an interface connected
to supply multiplexed electrical signal to the first ring port;
and, a third multiplexer having an interface connected to the ring
ports and the customer interface to receive electrical signals, and
an interface connected to supply multiplexed electrical signal to
the second ring port.
20. The ONU of claim 19 further comprising: a framer module having
an interface to accept a plurality of customer interface electrical
signals from a plurality of customer interfaces, and an interface
connected to the first, second, and third multiplexers to supply
the plurality of customer interface electrical signals framed into
a GPON signal.
21. A system of ring-connected optical network units (ONU) for
distributing signals, the system comprising: a plurality of ONUs,
each ONU including: an optical port for transceiving optical
signals; an optical-to-electrical translation module having an
interface connected to the optical port, and an interface for
transceiving electrical signals; a first (North) ring port
connected to the translation module to transceive electrical
signals between a first ONU neighbor; a second (South) ring port
connected to the translation module to transceive electrical
signals between a second ONU neighbor; and, a customer interface
port to transceive customer interface electrical signal with a
user.
22. The system of claim 21 wherein the translation module of each
ONU converts an encrypted optical signal into an encrypted
electrical signal; wherein the first and second ring ports
distribute encrypted electrical signals; and, each ONU further
comprising: a deframer module having an interface connected to the
translation module and an interface to supply a decrypted
electrical signal to the customer interface.
Description
RELATED APPLICATIONS
[0001] This application is a Continuation of a pending application
entitled, OPTICAL TRANSCEIVER WITH ELECTRICAL RING DISTRIBUTION
INTERFACE, invented by Miller et al., Ser. No. 11/395,858, filed
Mar. 31, 2006, attorney docket no. applied.sub.--161, which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention generally relates to digital communications
and, more particularly, to a system for efficiently distributing
electrical communications signals, converted from optical network
communications, via a ring of optical network units (ONUs).
[0004] 2. Description of the Related Art
[0005] FIG. 1 is a schematic block diagram depicting a "triple
play" system for distributing optical communication signals to a
customer premise (prior art). A optical line terminal (ONT)
broadcasts a ITU-T G.984.3 PON (GPON) optical signal out to many
ONUs, which are typically outside units, or to many optical network
terminals (ONTs), which are typically indoor units. The ONUs (ONTs)
convert the GPON optical signal into video, telephone, and Ethernet
electrical signals for use in the customer premise. The responses
back from the various ONUs (ONTs) are converted to a GPON optical
signal and time division multiplexed (TDM) back to the OLT. A
typical single-family unit (SFU) may have four Ethernet ports.
[0006] Additional issues are presented when an OLT is interfaced
with a multi-dwelling unit (MDU), such as an apartment building.
Currently, there are two methods of interfacing an OLT to an MDU.
One option is place an ONU in each apartment, and run optical fiber
to each ONU. This option is hardware expensive, because multiple
copies of the optic fiber must be run in parallel to each ONU.
Alternately, a single ONU is assigned to the MDU. However, the ONU
must have a network processor and Ethernet switch to bring out
multiple ports. This option is software expensive, because software
must be written to configure the network processor and Ethernet
switch. Further, a policing function must be enabled to guarantee
each user a Service Level Agreement (SLA) that includes some
measure of privacy protection.
[0007] It would be advantageous if an MDU could be interfaced to an
OLT GPON optical signal with a minimum expenditure of software and
hardware assets, and development costs.
SUMMARY OF THE INVENTION
[0008] The present invention presents an ONU device that can
convert GPON optical signals to a GPON electrical signal, for
distribution in a system of ring-connected ONUs. Each ONU has three
high-speed connections. One interface transceives optical signals
(e.g., 2.5 GPON). There are also a ring North Rx/Tx interface, and
a ring South Rx/Tx interface for electrical signals. In this
manner, an entire multi-dwelling unit can be interfaced to the OLT
via a single optical connection to just one of the ONUs. A second
optical line may be run to another of the ONUs, if additional
(redundant) optical protection is desired. Otherwise, the converted
optical signal is distributed through the ring via the ring North
and/or ring South interfaces.
[0009] Accordingly, a ring connection method is provided for
distributing signals in an optical-to-electrical interface. The
method electrically connects a plurality of nodes in a
series-connected ring, and receives an optical signal at a first
node from a service provider. The method converts the optical
signal to an electrical signal, and distributes the electrical
signal via the ring. At each node, the electrical signal is
supplied from a customer interface. Typically, each node has a
plurality of customer interfaces.
[0010] In one aspect, ITU-T G.984.3 Giagbit-capable Passive Optical
Network (GPON) optical signals are received and converted to a
customer interface electrical signal such as an Ethernet,
asynchronous transfer mode (ATM), or time division multiplexed
(TDM) signal.
[0011] Electrically connecting the plurality of nodes in the
series-connected ring includes: series connecting the nodes in a
first (North) ring; and, series connecting the nodes in a second
(South) ring, opposite in direction from the first ring.
[0012] In another aspect, the method receives a customer interface
electrical signal from a customer interface at each node. The
received customer interface electrical signals from each node are
multiplexed, and the multiplexed signals are distributed via the
ring. Then, the multiplexed signals are converted to an optical
signal, and transmitted to the OLT service provider.
[0013] Additional details of the above-described method, a
ring-connected ONU, and a system of ring-connected ONUs are
provided below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic block diagram depicting a "triple
play" system for distributing optical communication signals to a
customer premise (prior art).
[0015] FIG. 2 is a schematic block diagram of a system of
ring-connected optical network units (ONU) for distributing
signals.
[0016] FIG. 3 is a schematic block diagram of a ring-connected ONU
for distributing signals.
[0017] FIG. 4 is a schematic block diagram depicting downlink
communication details of an exemplary ONU.
[0018] FIG. 5 is a schematic block diagram depicting uplink
communication details of an exemplary ONU.
[0019] FIGS. 6A and 6B are flowcharts illustrating a ring
connection method for distributing signals in an
optical-to-electrical interface.
DETAILED DESCRIPTION
[0020] FIG. 2 is a schematic block diagram of a system of
ring-connected optical network units (ONU) for distributing
signals. The system 200 comprises a plurality of ONUs. Shown are
ONUs 202, 204, 206, and 208. In other aspects, up to 64 ONUs may be
ring-connected. However, it should be understood that the system is
not inherently limited to any particular number of ONUs.
[0021] FIG. 3 is a schematic block diagram of a ring-connected ONU
for distributing signals. ONU 204 of FIG. 2 is used as an example,
however, the following description could also be applied to the
other ONUs in the system. ONU 204 comprises an optical port on line
300 for transceiving optical signals. An optical-to-electrical
translation module 302 has an interface connected to the optical
port on line 300, and an interface for transceiving electrical
signals.
[0022] A first (North) ring port is connected to the translation
module 302 on line 306 to transceive ring-connected electrical
signals between a first ONU neighbor (i.e., ONU 202 of FIG. 2). A
second (South) ring port connected to the translation module 302 on
line 308 to transceive ring-connected electrical signals between a
second ONU neighbor (i.e., ONU 206 of FIG. 2). A customer interface
port on line 310 transceives customer interface electrical signals
with a user.
[0023] Typically, a common downlink (downstream) signal is sent
from the service provider (OLT) to all the users on line 300.
However, to control distribution of the signal, the signal is
decrypted before it is provided to a user. For example, only
customers paying a service charge to the service provider receive
decrypted customer interface electrical signals. In this aspect,
the translation module 302 converts an encrypted optical signal
into an encrypted electrical signal. The encrypted electrical
signal is distributed via the first and second ring ports, on lines
306 and 308, respectively. A deframer module 312 has an interface
connected to the translation module on line 314 and an interface on
line 310 to supply a decrypted electrical signal to the customer
interface.
[0024] In one aspect, the translation module 302 receives a ITU-T
G.984.3 Giagbit-capable Passive Optical Network (GPON) signal on
line 300 and converts the GPON optical signal into a GPON
electrical signal, which is provided on lines 306, 308, and 314.
The deframer module 312 converts the GPON electrical signal into a
customer interface electrical signal.
[0025] Typically, there is a plurality of customer interfaces
connected to the deframer module 312, each transceiving customer
interface electrical signals with a user. Shown are four customer
interfaces (310, 316, 318, and 320) per ONU. However, the ONU is
not inherently limited to any particular number of customer
interfaces. The deframer module 312 time division demultiplexes a
GPON signal on line 314 into a customer interface electrical signal
for each customer interface. For example, the customer interface
electrical signal can be an Ethernet, asynchronous transfer mode
(ATM), or time division multiplexing (TDM) signal. However, the
deframer module 312 is not limited to any particular format or
protocol.
[0026] In one aspect, each ONU further comprises a downlink
multiplexer 321 having an interface connected to the ring ports on
lines 306 and 308, and the translation module on line 314 to
receive (GPON) electrical signals. The downlink MUX 321 has an
interface connected to the deframer 312 on line 323 to supply a
multiplexed (GPON) electrical signal.
[0027] With respect to the uplink, a first multiplexer (MUX) 322
has an interface connected to the ring ports on lines 306 and 308,
as well as to the customer interface(s) (e.g. 310) to receive
electrical signals. An interface is connected to the translation
module 302 on line 324 to supply a multiplexed electrical signal.
The translation module 302 converts multiplexed electrical signals
into an optical signal, and transmits the optical signal on line
300.
[0028] In another aspect, a second multiplexer 326 has an interface
connected to the ring ports 306 and 308 and the customer
interface(s) (e.g. 310) to receive electrical signals. The second
multiplexer 326 has an interface connected to supply multiplexed
electrical signal to the first ring port on line 306. Likewise, a
third multiplexer 328 has an interface connected to the ring ports
306 and 308 and the customer interface(s) (e.g., 310) to receive
electrical signals. An interface is connected to supply multiplexed
electrical signal to the second ring port on line 308.
[0029] The uplink messages to the OLT (service provider) are
typically originated by the user. Therefore, security and
eavesdropping protection from other users is a desirable feature.
In one aspect, a framer module 330 has an interface to accept a
plurality of customer interface electrical signals from a plurality
of customer interfaces (e.g., 310, 316, 318, and 320). Again the
framer module 330 is not limited to any particular number of
customer interfaces. The framer module 330 has interface connected
to the first, second, and third multiplexers on line 332 to supply
the plurality of customer interface electrical signals framed into
a GPON signal. In the event of an evolution in the GPON standard,
or the use of a different optical standard, the framer module 330
can also be used to encrypt the customer interface electrical
signals.
[0030] Note, although ONU 204 is shown with a connected and
operating optical interface 300. Other ONUs in the ring-connected
system (e.g. 202, see FIG. 2) need not necessarily have a connected
optical interface to receive optical signals. That is, an ONU with
an optical connection can receive converted optical signals from
ONU 204 communicated via the ring connection. In another aspect, an
ONU (i.e., ONU 206, see FIG. 2) may be connected to a backup line
which can be selectively engaged is the main optical line develops
a fault. Alternately, the protection optical line may continually
send optical signals, but the ONU's translation module is
selectively enabled to only convert optic/electrical signals in the
event that the main optical line fails or ONU 204 fails.
Functional Description
[0031] Returning briefly to FIG. 2, each ONU has three potential
high-speed interfaces: the optical (2.5 GPON) interface, the ring
North interface, and the ring South interface. For the
multi-dwelling case, a first ONU chip on a system board is hooked
to the optical interface. A second ONU chip can be hooked to an
optics line if optical protection is necessary. Otherwise,
converted optical communications are distributed via the ring North
and ring South interfaces. The system of FIG. 2 utilizes two types
of protection. The main and protection lines provide 1+1 Optical
protection, while the bidirectional rings provide protection from
an ONU malfunction.
[0032] In the downlink direction, the OLT controls how much
bandwidth each user receives. From the point of view of the OLT,
the OLT cannot determine if it is communicating with a plurality of
single family units (SFUs) or one Multi-Dwelling unit equipped with
a ring-connected ONU system. Thus, the software used in both the
OLT and ONT need not be modified, and the need for multiple optical
receivers is eliminated.
[0033] FIG. 4 is a schematic block diagram depicting downlink
communication details of an exemplary ONU. Note that the ring input
and output can combined either before, or after decryption.
Typically, there is only a single key per ONU, however in other
aspects, a separate decryption key can be used for each of the four
Ethernet ports. The ring connections easily support 1+1 optical
protection. Because the ONU's are in a ring, every ONU can "see"
the protection signal after it has switched over from the main
optical signal. This architecture permits each Ethernet customer
interface port to have a dedicated protected bandwidth.
[0034] FIG. 5 is a schematic block diagram depicting uplink
communication details of an exemplary ONU. The uplink (upstream)
bandwidth is assigned by the OLT using a bandwidth map. The
bandwidth map allocates a certain number of upstream timeslots to
each traffic container (TCONT). In this manner, the OLT can control
the uplink bandwidth assigned to each Ethernet customer interface
port.
[0035] Without this architecture, an Ethernet switch would be
required for the multi-dwelling scenario, which would require the
addition of hardware to control how much uplink bandwidth is
assigned to each customer interface port. However, if the ONU chips
are ring-connected as shown in FIGS. 2 and 5, then each Ethernet
customer interface port gets it's own traffic container. From the
point of view of the OLT, the OLT cannot determine if it is
connected to four transmitting SFU's, or one MDU enabled with a
ring-connected system with four ONUs. Thus, the ONU and OLT
software need not be changed to accommodate the ring-connected ONU
system. Note, FIG. 5 shows only a single MUX with an output
connected to the optical interface. In other aspects, MUXs having
the same inputs as the displayed MUX are used, one MUX for each
ring connection (see FIG. 3).
[0036] FIGS. 6A and 6B are flowcharts illustrating a ring
connection method for distributing signals in an
optical-to-electrical interface. Although the method is depicted as
a sequence of numbered steps for clarity, the numbering does not
necessarily dictate the order of the steps. It should be understood
that some of these steps may be skipped, performed in parallel, or
performed without the requirement of maintaining a strict order of
sequence. The method starts at Step 600.
[0037] Step 602 electrically connects a plurality of nodes in a
series-connected ring. Step 604 receives an optical signal at a
first node from a service provider (OLT). Step 606 converts the
optical signal to an electrical signal. Step 608 distributes the
electrical signal via the ring. Step 610 supplies the electrical
signal from a customer interface at each node. In one aspect, Step
610 supplies a plurality of customer interface electrical signals
from a corresponding plurality of customer interface ports at each
node.
[0038] In one aspect, receiving the optical signal from the service
provider in Step 604 includes receiving a ITU-T G.984.3
Giagbit-capable Passive Optical Network (GPON) signal. Then,
converting the optical signal to the electrical signal in Step 606
includes converting to a customer interface electrical signal such
as an Ethernet, ATM, or TDM signal. Typically, Step 610 time
division demultiplexes the GPON signal into the plurality of
customer interface electrical signals.
[0039] In another aspect, electrically connecting the plurality of
nodes in the series-connected ring in Step 602 includes substeps.
Step 602a series connects the nodes in a first (North) ring. Step
602b series connects the nodes in a second (South) ring, opposite
in direction from the first ring.
[0040] In a different aspect, converting the optical signal to the
electrical signal in Step 606 includes converting an encrypted
optical signal into an encrypted electrical signal. Then, supplying
the electrical signal from the customer interface in Step 610
includes selectively decrypting the encrypted electrical signal at
each node. In another aspect, Step 610 multiplexes customer
interface electrical signals that are supplied from ring-connected
nodes. If the node (e.g. the first node) happens to be directly
connected to the optical interface, as opposed to being indirectly
connected via the bidirectional ring interface, then the converted
optical signal is multiplexed together with the electrical signals
supplied by the ring-connected nodes. A multiplexed customer
interface electrical signal is then supplied to a customer
interface.
[0041] In one aspect, Step 603a accepts a first (Working) optical
signal at the first node. Step 603b accepts a second (Protection)
optical signal at a second node. Then, receiving the optical signal
from the service provider in Step 604 includes substeps. Step 604a
initially converts the first optical signal to an electrical
signal. Step 604b converts the second optical signal to the
electrical signal in the event of an optical line fault.
[0042] In another aspect, Step 612 receives a customer interface
electrical signal from a customer interface. At each node, Step 614
multiplexes the received customer interface electrical signals from
each node. Step 616 distributes the multiplexed electrical signals
via the ring. Step 618 converts the multiplexed electrical signals
into an optical signal. Step 620 transmits the optical signal to
the service provider.
[0043] In one aspect, receiving the electrical signal from the
customer interface at each node (Step 612) includes substeps. Step
612a accepts a plurality of customer interface electrical signals
from a plurality of customer interfaces. Step 612b frames the
plurality of customer interface electrical signals into a GPON
signal.
[0044] An optical/electrical interface system and method have been
provided for the ring connection distribution of electrical
signals. Some examples of particular subcircuits, circuit
connections, and communication protocols have been given to
illustrate the invention. However, the invention is not limited to
merely these examples. Other variations and embodiments of the
invention will occur to those skilled in the art.
* * * * *