Marconi Communications Gmbh

Tellabs Bedford, Inc.

Advanced Fibre Access Corporation

Tellabs Beford, Inc.

Mahlon Danny Kimbrough

Barry Joe Ethridge

James Joseph Gainer

Craig Lawrence Lutgen

John W Matthes

Joseph L Whitehead

Michael R Cosley

George H BuAbbud

Edwin Glenn Yancey

Thomas Ray Dobozy

William I Chen

Mark Hastings

Timothy D Adcox

James Zipper

An embodiment of the invention provides communications services to Optical Network Terminals (ONTs) in a Passive Optical Network (PON) with at least two Optical Line Terminals (OLTs). The role of these OLTs is autonomously governed based on characteristics of upstream signals from the ONTs. When an OLT in a standby mode determines that upstream signal power is below a power threshold, the OLT in standby mode changes its mode and operates in the active mode. An OLT in active mode monitors the upstream signals and determines the number of upstream signals that are misaligned to a respective downstream command sent from the active OLT. When the number of misaligned signals is greater than a counts threshold, the active OLT switches its operation and operates in standby mode. Through autonomous operation, the OLTs provide redundancy for the PON without added control channel complexity.

Passive optical networking redundancy via two or more auto sensing optical line terminals

Typical passive optical networks (PONs) employ several optical network terminals (ONTs) connected to an optical line terminal (OLT) via an optical splitter/combiner (OSC). Due to the passive nature of the OSC, determining a port assignment of an ONT may be difficult or impossible. Methods described herein provide for identifying a port in a passive optical network, optionally as corresponding to an ONT. A first subset of the ONTs is caused to transmit a first signal, such as a status signal, with a respective attribute having a first value, and a second subset of the ONTs is caused to transmit a second signal with the respective attribute having a second value. At the OSC, the signals are detected as a function of the attribute and the first and second values. Results of this detection are reported, from which an identification of a port and associated ONT can be determined.

Method and apparatus for identifying a port in a passive optical network

A media access control (MAC) layer address translation system is included in a fiber to the home (FTTH) system having a central office that interfaces a packet data network with a passive optical network (PON). The (MAC) layer address translation system includes a home network unit (HNU), a host system, and a MAC address table. The HNU is coupled to the PON and has an associated base MAC layer address and an associated secondary MAC layer address that identify the HNU within the PON. The host system is coupled in a network to the HNU and has an associated host MAC layer address that identifies the host system within the network. The MAC address table is stored in a memory device, and associates the host MAC layer address with the secondary MAC layer address. Upon receiving an outgoing transmission from the host system that includes the host MAC layer address, the HNU accesses the MAC address table to determine the secondary MAC layer address that is associated with the host MAC layer address and modifies the outgoing transmission to replace the host MAC layer address with the secondary MAC layer address.

Media access control address translation for a fiber to the home system

A technique for multiplexing high speed computed data with digitized voice signals onto a fiber optic cable for transfer to a local central office. The data packets of a number of computers are networked by way of a distributed hub that extends to residences, offices, apartments, etc. The data packets are switched outside the switching fabric of a local central office and routed to the internet or elsewhere. Command signals that are for accessing the internet are transmitted and received as 10 MHz Ethernet data packets on the distributed hub.

Distributed ethernet hub

A digital packet access network for transporting voice and data signals in the local loop between a central office location and a plurality of remote local users. The network architecture may also include: (1) a dual-pipelined structure for separately transporting the voice and data signals; (2) a mechanism for prioritizing the transport of the voice signals; or (3) a method of synchronizing the timing of the voice signals to a telephone switch.

Digital packet network for the local access loop

An improved digital loop carrier system for transporting voice and DSL data signals in the local loop. The digital loop carrier system includes a remote digital terminal having an interface terminal, a common equipment shelf for interfacing digital voice signals to the central office switch, and a plurality of copper shelves coupled to the common shelf for holding voice line-cards that convert digital voice signals into analog voice signals (and vice versa) for transport to customer premises. At least one copper shelf is configured to include an auxiliary packet data bus for connecting combination voice/DSL line-cards and at least one data uplink card. The data uplink card is coupled to the interface terminal to enable DSL data transport without impacting digital voice capabilities through the common equipment. Also disclosed is an optional Ethernet switch in the remote digital terminal for concentrating multiple DSL signals prior to transport back to the central office.

Adding DSL services to a digital loop carrier system

A digital laser driver circuit is provided in which a digital synthesizer synthesizes a modulation index signal for precisely setting the modulation level of the laser, and a pair of feedback loops control the average power level and modulation index of the laser diode. The laser diode includes a back-facet photodiode that is used to monitor the laser's average and peak optical power levels. The average power level is measured by an analog feedback loop and compared to an externally supplied reference voltage in order to maintain the laser at a particular average optical power level. The peak power is measured by a digital feedback loop and compared to a pair of threshold levels based on a ratio of the average power level using digital comparators. The comparators provide signals to the digital synthesizer in order to indicate that the modulation level is too low or too high. The digital synthesizer then re-synthesizes the laser modulation index signal to maintain the optical modulation between the two threshold levels.

Digital laser driver circuit

A linear laser diode driver circuit is provided in which a solid state laser diode and its back-facet photodiode are configured into the feedback loop of a high-speed operational amplifier. In this configuration, the light output from the laser diode is directly proportional to the input voltage to the operational amplifier and is independent of the laser diode's temperature characteristics.

Linear laser driver circuit

Circuitry for controlling a diode optically coupled to an optical fiber suitable for transmitting digital light signals therethrough. The circuitry includes a temperature compensated driver when operating in the transmit mode and receiving circuitry for conditioning and amplifying electrical signals generated by the diode when it operates in a photodetection mode. A sweep circuit is provided for isolating amplifiers in the receiving circuitry and for discharging residual charge left in the diode during the transmission mode thereby reducing the signal-to-noise ratio.

Method and apparatus for converting electrical signals and optical signals for bidirectional communication over a single optical fiber

An ONU includes circuit cards, a card cage, and electrical connector hardware. The card cage releaseably engages and supports the circuit cards in installed positions in the card cage. At least one pair of the circuit cards have serial interconnections with each other. The electrical connector hardware defines all of those serial interconnections and is free of a backplane.

Card cage for circuit cards in an optical network unit

A multi-service, adaptable optical network unit (ONU) is disclosed for use in a fiber-to-the-curb (FTTC) digital loop carrier system, including a multi-service common card and a plurality of multi-media service cards that are connected to the common card using a card-link interface. The card-link interface is preferably a high-speed LVDS serial-bus connection that is organized in a star configuration such that each service card is connected to the multi-service common card using a separate point-to-point card-link. By eliminating the traditional backplane structure found in present ONU designs, the present invention provides a scalable, adaptable, future-proof FTTC system that can transport present-day multi-media services as well as yet-to-be-defined future high-bandwidth applications.

Multi-service adaptable optical network unit

A digital packet access network for transporting voice and data signals in the local loop between a central office location and a plurality of remote local users. The network architecture may also include: (1) a dual-pipelined structure for separately transporting the voice and data signals; (2) a mechanism for prioritizing the transport of the voice signals, or (3) a method of synchronizing the timing of the voice signals to a telephone switch.

A four quadrant power conversion topology comprising a multi-winding inductor, four switches, and four diodes is disclosed. The four quadrant power conversion is utilized in a number of power conversion devices such as a power efficient non-linear power amplifier that comprises the 4Q power conversion topology of the present invention and a switch-control-signal generator coupled to the 4Q power conversion topology. The switch-control-signal generator generates switch activation signals for driving the four switches of the 4Q power conversion topology. In one embodiment the switch-control-signal generator comprises a polarity detector for detecting the polarity of an input signal, a full wave rectifier for rectifying the input signal, a pulse width modulator which produces a pulse width modulated signal representative of the full wave rectified input signal, and steering logic that generates switch activation signals for driving the power conversion topology to produce an output representative of the input signal. The amplifier may optionally include switch drivers to condition the switch activation signals to drive the switches in the 4Q power conversion topology.

Growing community of inventors

Bedford, TX, United States of America

Mahlon Danny Kimbrough