Telefonaktiebolaget Lm Ericsson (publ)

Antonio D'errico

Francesco Testa

Marzio Puleri

Luca Giorgi

Giulio Bottari

Paola Iovanna

Antonella Bogoni

Luca Poti

Ernesto Ciaramella

Fabrizio Di Pasquale

Gianluca Berrettini

Gianluca Meloni

Mauro Rudi Casanova

Francesco Giurlanda

Veronica Tinucci

Paolo Pintus

A method for monitoring a passive optical network, the passive optical network comprising a plurality of network components, comprises receiving an alert message () from a fault detection system associated with the passive optical network, the alert message comprising an indication of one or more candidate locations for a detected fault in the passive optical network. The method further comprises accessing an inventory () of the plurality of network components, the inventory storing, for each of the plurality of network components, information comprising the network component location. The method further comprises identifying (), based on the one or more candidate locations and the network component locations, one or more network components of the plurality of network components as candidates for the cause of the detected fault.

Methods and apparatus for maintenance in an optical communication network

A data center network node () comprises one or more switch () configured to link an optical transceiver () to an optical connection comprising a multi-core optical fiber () having a plurality of cores (). For each core (), the one or more switch () is configurable between a first configuration in which an optical signal on a said core () of the multi-core optical fiber bypasses the optical transceiver and a second configuration in which the optical transceiver is optically linked to the said core () of the multi-core optical fiber ().

Data center network node

Anode for burst switching of traffic flows in an optical network switches bursts of traffic flows in different time slots. Time slots are allocated () so that a time gap between successive allocated time slots is selected according to a jitter specification of the traffic flow. A map of the allocations controls a burst switch to pass the bursts in their allocated time slots (). By making the time gap between allocated time slots for successive bursts selectable, the jitter can be controlled more precisely, or the proportion of time slots filled can be increased resulting in better utilization of available bandwidth. The allocation can be made hop by hop. The map can be generated in a distributed and duplicated manner at each node. The allocation can be updated to adapt to changes bandwidth demands.

Time slot allocation for burst switched network

Optical add and drop switch and aggregator apparatus comprising: N first wavelength selective routing apparatus each configured to split a wavelength multiplexed input signal into L sub-signals; demultiplexers each configured to demultiplex a respective sub-signal into K optical signals; output ports each configured to output a respective output optical signal; add ports configured to receive optical signals to be added; M second wavelength selective routing apparatus each having X outputs, each said apparatus being configured to receive optical signals from a respective add port and to route each received optical signal to a respective one of its outputs; drop ports configured to output optical signals to be dropped; and a switch matrix coupled between the demultiplexers, the output ports, the drop ports and the second wavelength selective routing apparatus, the switch matrix comprising a plurality of optical switches arranged in XM columns and KLN rows.

Optical routing apparatus and method

Phase shift keying optical modulation apparatus comprising optical phase shifting apparatus and an optical modulator. The optical phase shifting apparatus is arranged to receive an optical carrier signal and is arranged to selectively apply a preselected optical phase shift to the optical carrier signal in dependence on a symbol of a 2N-level phase shift keying modulation format to be encoded onto the optical signal. The optical modulator is arranged to receive the optical carrier signal from the optical phase shifting apparatus and is arranged to apply a phase modulation to the optical carrier signal in dependence on the symbol, to thereby encode the symbol onto the optical carrier signal. The phase modulation is a phase-modulation of an N-level phase shift keying modulation format.

Phase shift keying optical modulation apparatus and method of encoding a symbol onto an optical carrier signal

Path computation involves determining () an aggregate cost for a portion of the path, based at least on the power consumption attributable to use of interfaces along that portion, comparing () the portion of the first possible path with a different portion corresponding to a different possible path for the traffic request, based at least on their respective aggregate costs, and selecting () which portion to use for the traffic request based on the comparison. Having path selection influenced by the power consumption values, can lead to lower overall consumption in operation than relying only on optimizing nodes individually without regard to how the nodes are used. Path selection can take into account indications of which parts are in a power down mode, and can involve powering up such parts if needed.

Reducing network power consumption

An apparatus for an optical communications network comprising a demultiplexer, a plurality of add/drop optical switches for adding and dropping wavelength channels. The add/drop optical switches arranged in a matrix with a number of rows corresponding to a number of output ports of the demultiplexer and a number of columns corresponding to a number of transponders. Each drop optical switch has an express input port associated with an output port of the demultiplexer, a drop output port associated with an individual transponder, and an express output port. Each add optical switch has an express input port, an add input port associated with an individual transponder, and an express output port. The apparatus also comprises a multiplexer with a plurality of input ports associated with express output ports of the add/drop optical switches.

Add and drop switch/aggregator for optical communications networks

A free space optical communications link nodecomprising transmitter apparatuscomprising a first optical transmitter, arranged to transmit high priority traffic on a first upstream optical signal having a first wavelength and at a first optical signal power, and a second optical transmitterarranged to transmit low priority traffic on a second upstream optical signal having a second wavelength, different to the first wavelength, and at a second optical signal power. The nodefurther comprises receiver apparatuscomprising a first optical amplifierarranged to receive and amplify a first downstream optical signal having a third wavelength and carrying high priority traffic and a second downstream optical signal having a fourth wavelength, different to the third wavelength, and carrying low priority traffic. The nodefurther comprises traffic handling control apparatuscomprises a power monitorarranged to monitor an optical signal power of the first downstream optical signal and a controllerarranged to generate and transmit a control signalif said optical signal power is below a first threshold value. The control signal is arranged to cause the second optical signal power to have a value which is unsuitable for transmission.

Free space optical communications link node, network and method of transmitting traffic

A packet switchcomprises wavelength tunable optical transmitters, an optical switch fabric, optical detectorsand a controller. The transmittersare arranged to receive at least one electrical signal packet to be switched and convert it into a corresponding optical signal packet at an input wavelength. The optical switch fabriccomprises an ingress stagecomprising wavelength selective routersand an egress stagecomprising wavelength selective routersand tunable wavelength convertersarranged to receive an optical signal at the input wavelength and to output an optical signal at an output wavelength. The controlleris arranged to set the input wavelength of a transmitterand the output wavelength of a wavelength converter to configure a path across the switch fabricconnecting the transmitterto a detector. A communications network routercomprises an input module, a packet switch, an output moduleand a scheduler

Electrical signal packet routing

A wireless communications link comprising an RF link and a free space optics (FSO) link, a switch, an RF signal monitoring apparatus, an optical signal monitoring apparatus, alarm apparatus and a controller. The switch operates in a normal mode to aggregate the links to form a link aggregation group and to route traffic on the link aggregation group, a first protection mode to route traffic on the FSO link, or a second protection mode to route traffic on the RF link. The controller is arranged to receive an alarm signal and to generate and transmit a control signal to cause the switch to operate in the first protection mode when a first alarm signal is received, the second protection mode when a second alarm signal is received, and the normal mode when an indicator is received indicating that both signal quality parameters are above their threshold values.

Wireless communications links

A switching node for an optical communication system has an electrical switch, coupled to switch electrical signals from an input converter to a selected one of the outputs, and has a framer for reading or writing optical transport overhead information from or to the electrical signals. A bypass path is provided so that at least some of the signals being switched can bypass the framer. This can enable each node to be more efficient or handle more signals, since the framer no longer has to process all the signals. A reduction in power consumption can result. A method of configuring the switching node can involve a management system receiving information about the network, determining a new wavelength routing configuration and sending control signals to the node to configure the switches and control which signals use the bypass path.

Optical transport switching node with framer

An optical device comprises an optical device stage, which comprises an optical input, an optical AND gate, an optical flip-flop and an optical output. The optical input is arranged to receive an optical input pulse at an input wavelength. The optical AND gate comprises a first input arranged to receive a part of said optical input pulse, a second input arranged to receive at least a part of a flip-flop optical output signal, and an output. The optical AND gate is arranged to generate an AND gate optical output pulse dependent on said flip-flop optical output signal. The optical flip-flop comprises a first input arranged to receive a further part of said optical input pulse, a second input arranged to receive a said AND gate optical output pulse, and an output. The optical flip-flop is arranged to generate said flip-flop output signal at a flip-flop output wavelength. At least a part of the flip-flop output signal is provided to said output.

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Calci, Italy

Antonio D'errico