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Researchers Submit Patent Application, "Optical Access Network Having Emitter-Free Customer Premise Equipment and Adaptive Communication Scheduling",...

August 21, 2014



Researchers Submit Patent Application, "Optical Access Network Having Emitter-Free Customer Premise Equipment and Adaptive Communication Scheduling", for Approval

By a News Reporter-Staff News Editor at Computer Weekly News -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Sindhu, Pradeep (Los Altos Hills, CA); Boddu, Jayabharat (Los Altos, CA); Marcoccia, Roberto (San Jose, CA); Schmidt, Theodore John (Gilroy, CA); Malouin, Christian (San Jose, CA); Choudhury, Abhijit Kumar (Cupertino, CA); Murphy, James Michael (Alameda, CA), filed on March 31, 2014, was made available online on August 7, 2014.

The patent's assignee is Juniper Networks, Inc.

News editors obtained the following quote from the background information supplied by the inventors: "Various types of devices connect to service provider networks to access services provided by packet-based data networks, such as the Internet, enterprise intranets, and virtual private networks (VPNs). For example, many computers utilize fixed communication links, such as optical, digital subscriber line, or cable-based connections, of service provider networks to access the packet-based services. Similarly, wireless devices, such as cellular or mobile smart phones and feature phones, tablet computers, and laptop computers, utilize mobile connections such as cellular radio access networks of the service provider networks to access the packet-based services. In some cases, access networks make use of fiber optics to provide high-speed point-to-point connectivity between customer premise equipment (CPE) and an upstream access device.

"In this way, the service provider networks typically provide an extensive access network infrastructure to provide packet-based data services to service provider network access devices to provide access to the offered services. Access devices, such as high-speed aggregation routers, are often positioned near the edge of the service provider network upstream from the CPEs and typically provide an anchor for managing subscriber sessions. The access devices typically provide mechanisms for identifying subscriber traffic and apply subscriber policies to manage subscriber traffic on a per-subscriber basis as such traffic traverses the service provider core network boundary."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "In general, an access network is described that provides a comprehensive solution to limitations of current access networks. As further described herein, the techniques may allow a service provider to leverage existing optical infrastructure yet achieve a significant degree of statistical multiplexing gain ('stat mux gain') with respect to the infrastructure. This, in turn, may allow the service provider to amortize a cost associated with high-end components of the access network across significantly more subscribers than current access networks allow.

"In one example, an access device, such as an access router, is described that provides an optical interface capable of optically communicating with a plurality of different customer premise equipment (CPE) through a common optical interface. The access router may, for example, communicate with the CPEs through a passive optical network using wave division multiplexing. As such, a set of CPEs serviced by the common optical interface of the access router may communicate with the access router using a different wavelength. That is, in this example, the optical interface of the router transmits modulated optical communications to the CPEs at particular wavelengths for different set of CPEs. An N port (e.g., 40 port) comb filter may, for example, be used for wave division multiplexing the modulated optical signal at each wavelength to respective downstream sets of one or more CPEs, thereby providing for concurrent downstream communication through a common optical interface of the access router.

"Further, techniques are described for incorporating low-cost, optical emitter-free CPEs within the access network. For example, in addition to outputting a modulated optical transmit signal to each CPE, the optical interface of the access router outputs a separate, non-modulated optical carrier at each of the wavelengths to be used by the CPEs for subsequent upstream communications. As explained herein, each of the CPEs may incorporate a specialized optical interface that utilizes reflective optics for upstream communications. Each of the CPEs receives the non-modulated optical carrier at a particular wavelength depending upon the port of the comb filter to which the subscriber device is connected, modulates the optical carrier with any data to be transmitted upstream, and reflects the optical carrier in modulated form upstream to the access router. In some cases, the non-modulated optical carrier may be at a different wavelength than its associated modulated optical transmit signal.

"In this way, multiple CPEs are able to achieve bi-directional communication with the access router through a single optical interface of the access router even though the CPEs are optical emitter (e.g., laser) free. Moreover, each CPE may utilize a broadband modulator, i.e., a modulator that is relatively insensitive to wavelength, to modulate the upstream optical carrier signal received from the access router. As such, each CPE need not include specialized interface components tailored for particular wavelengths and may avoid the cost associated with laser-based transmitters. As such, low-cost CPEs may be achieved that may be easily deployed to subscribers without regard to, or needing configuration for, specific wavelengths or ports of the comb filters used within the access network. In this way, a low-cost, low-complexity, highly-scalable access network may be achieved that provides high-speed, bi-directional optical communications.

"In some examples, the access network may further utilize optical splitters for the optical communications associated with each of the different wavelengths provided by the optical interface of the access router. For example, each port of the comb filter may be connected to an optical splitter so as to provide the upstream and downstream optical signals for that wavelength to a plurality of different CPEs for communicating at the same wavelength. An optical interface of the access router provides an execution environment for a plurality of schedulers, one for each port of the comb filter coupled to the optical interface, i.e., one for each wavelength. Each scheduler dynamically services data transmission requests for the set of CPEs communicating at the given wavelength, i.e., the set of CPEs coupled to a common port of the comb filter by an optical splitter, thereby allowing the access network to dynamically schedule data transmissions so as to utilize otherwise unused communication bandwidth.

"In one example, a network system comprises an access device comprising an optical interface module that outputs a plurality of pairs of optical communication signals, each of the pairs of optical communication signals comprising a modulated optical transmit signal and an unmodulated optical receive signal, each of the pairs of optical communication signals having a different wavelength; and a customer premise equipment (CPE) comprising an optical interface module to receive the modulated optical transmit signal and the unmodulated optical receive signal for any of the plurality of pairs of optical communication signals, wherein the optical interface module includes a receive module to demodulate the modulated optical transmit signal into inbound symbols and a transmit module having an optical modulator and reflective optics to modulate the unmodulated optical receive signal in accordance with a data signal and reflect a modulated optical receive signal to communicate outbound data symbols to the access device.

"In another example, a method comprises outputting, with an optical interface module of an access device, a plurality of pairs of optical communication signals, each of the pairs of optical communication signals comprising a modulated optical transmit signal and an unmodulated optical receive signal, each of the pairs of optical communication signals having a different wavelength; receiving, with an optical interface of a customer premise equipment (CPE), the modulated optical transmit signal and the unmodulated optical receive signal of any of the plurality of pairs of optical communication signals;

"demodulating, with the optical interface of the CPE, the modulated optical transmit signal into inbound symbols; modulating, with the optical interface of the CPE, the unmodulated optical receive signal in accordance with a data signal to produce a modulated optical receive signal of outbound data symbols; and reflecting, with the optical interface of the CPE, the modulated optical receive signal back to the access device to communicate the outbound data symbols to the access device.

"In another example, an access device comprises a plurality of interfaces; and a switch fabric to forward network packets between the plurality of interfaces, wherein at least one of the interfaces comprises an optical interface module that outputs a plurality of pairs of optical communication signals, and wherein each of the pairs of optical communication signals comprises a modulated optical transmit signal to transmit outbound symbols to a respective customer premise equipment (CPE) and an unmodulated optical receive signal to receive inbound symbols from the respective CPE.

"In another example, a method comprises outputting, with an optical interface module of an access device, a plurality of pairs of optical communication signals to a plurality of customer premise equipment (CPE), each of the pairs of optical communication signals comprising a modulated optical transmit signal to transmit outbound symbols to a respective set of one or more of the CPEs and an unmodulated optical receive signal to receive inbound symbols from the respective set of the CPEs; receiving, from the CPEs, the optical receive signals as modulated and reflected back by the CPEs; and demodulating the optical receive signals to recover inbound symbols transmitted by the CPEs.

"The method may further comprise scheduling, for each of the pairs of optical communication signals, (i) downstream communication to the CPEs by the modulated optical transmit signals, and (ii) upstream communication from the CPEs by the optical receive signal.

"The method may further comprise scheduling the upstream communication from the CPEs based on round trip delay times for the unmodulated optical receive signals output to the CPEs by the access device so output symbols transmitted by the CPEs arrive at the access device at different communication time slots.

"The method may further comprise forwarding the recovered inbound symbols to a network as packet-based communications.

"As another example, a customer premise equipment comprises an optical interface module to receive a modulated optical transmit signal and an unmodulated optical receive signal from an access device, wherein the optical interface module comprises: a receive module to demodulate the modulated optical transmit signal into inbound symbols; and a transmit module having an optical modulator and reflective optics to modulate the unmodulated optical receive signal in accordance with a data signal and reflect a modulated optical receive signal to communicate outbound data symbols to the access device.

"The techniques described herein may provide certain advantages. For example, the techniques may allow a service provider to amortize a cost associated with a high-end access router across significantly more CPEs than current access networks allow. In other words, the techniques may be applied such that the access routers provide a significant degree of statistical multiplexing gain ('stat mux gain') to the service provider. The service provider may, therefore, be able to leverage existing passive infrastructure to support high-bandwidth, bursty communication requirements for high-volumes of subscribers (e.g., tens of thousands) without requiring the service provider to build-out additional infrastructure.

"Moreover, the advantages described herein may be achieved while utilizing low-cost, low-complexity CPEs that may be easily deployed and maintained within the access network. Further, existing, passive optical components of the access network may be utilized, thereby providing high-speed connectivity without requiring high expense associated with a wholesale upgrade to an expansive access network.

"The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

"FIG. 1 is a block diagram illustrating an example network system in accordance with techniques described herein.

"FIG. 2 is a schematic diagram illustrating one example of an optical access network of FIG. 1 in accordance with one or more techniques of this disclosure.

"FIG. 3 is a block diagram illustrating an example of a customer premise equipment of FIG. 2.

"FIG. 4 is a schematic diagram illustrating a second example of an optical access network.

"FIG. 5 is an example distance timing diagram illustrating downstream and upstream optical signals as a function of distance

"FIG. 6 is a block diagram illustrating an example access router having an optical interface component that utilizes a plurality of ingress schedulers.

"FIG. 7 is a block diagram illustrating one example of a distributed phase lock loop (PLL) for the network systems described herein."

For additional information on this patent application, see: Sindhu, Pradeep; Boddu, Jayabharat; Marcoccia, Roberto; Schmidt, Theodore John; Malouin, Christian; Choudhury, Abhijit Kumar; Murphy, James Michael. Optical Access Network Having Emitter-Free Customer Premise Equipment and Adaptive Communication Scheduling. Filed March 31, 2014 and posted August 7, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=3534&p=71&f=G&l=50&d=PG01&S1=20140731.PD.&OS=PD/20140731&RS=PD/20140731

Keywords for this news article include: Juniper Networks Inc.

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Source: Computer Weekly News


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