Telefonaktiebolaget Lm Ericsson (publ)

Finisar Corporation

Peter Öhlén

Stefan Dahlfort

Kim Laraqui

Einar In De Betou

David Hood

Giulio Bottari

Luca Giorgi

Ming Xia

Björn Skubic

Aldebaro Klautau

Ahmad Rostami

Jiajia Chen

Zere Ghebretensaé

Mateus Santos

Pedro Batista

Lena Wosinska

Forough Yaghoubi

Methods, apparatuses and computer programs are disclosed. The method of allocating network resources to a plurality of media flows in a communications network, the method comprising the steps of: determining a media content characteristic for the plurality of media flows; partitioning the plurality of media flows into one or more media flow groups based on the media content characteristic; initiating allocation of a separate network resource pool to the one or more media flow groups to be used by media flows belonging to respective media flow group.

Allocating network resources to media flows

An optical communications network has an interconnecting node () coupled in between at least one hub node () and at least first () and second () access nodes, to provide working and protection optical paths. The interconnecting node has a working wavelength selective switch () to select which working wavelengths are coupled. A corresponding protection wavelength selective switch () is also provided for the protection wavelengths. In the event of detection of a fault, protection switching () is carried out at the access node and the hub node without altering the selections made by the wavelength selective switches in the interconnecting node. Thus protection schemes across the interconnecting node for more than one access node can be handled. By not needing to alter wavelength selections at the interconnecting node during protection switching operation, the complexity and thus costs can be reduced.

Protection switching across interconnecting node

A system and method in a wavelength division multiplexing passive optical network is provided. A multiplexed optical downstream signal is transmitted from an optical line terminal to a passive distribution node. The signal is demultiplexed into a plurality of optical sub-signals. A sub-signal is transferred to an optical network termination. The received at least one sub-signal is identified. An optical wavelength of an upstream optical signal is set as a function of a predefined relationship between an optical wavelength of the received at least one sub-signal and the optical wavelength of the upstream signal. The upstream signal is transmitted to the optical line terminal via the passive distribution node.

Method and devices for automatic tuning in WDM-PON

A method performed by a network node in a communication network is disclosed for controlling connectivity of a radio resource unit (RRU) to a baseband unit (BBU) in the communications network. The communication network comprises a plurality of RRUs and a plurality of BBUs, each RRU being connected to a BBU via a distribution network. The method comprises receiving information indicating that a connection of a first RRU to a first BBU is to be controlled and triggering a user equipment (UE) connected to the first RRU to perform measurements on signals from neighboring RRUs and to send a report of the performed measurements to the communications network. The method further comprises receiving the report of the performed measurements, and selecting a BBU, out of the plurality of BBUs, to which the first RRU is to be connected, based on the report of performed measurements and on information regarding to which of the plurality of BBUs the neighboring RRUs are connected.

Network node and method performed by a network node for controlling connectivity of a radio resource unit to a base band unit

A method at a transmitter of a tunable laser of controlling a mode change of the laser during a transmission of data to a receiver of a terminating node is based on the determination of a time instance for initiation of the mode change on the basis of the state of the tunable laser. In addition, buffer occupancy and/or the state of the data transmission may be considered when determining such a time instance. In addition, data of the data transmission is buffered during the mode change, such that data loss is avoided during the change of mode. A transmitter is also provided which can execute the suggested mode changing method.

Method and apparatus for changing a mode in an optical network

Methods and apparatus for a network element or server end station to determine an estimated physical location of a fault in a communications link utilized by two network elements. In an embodiment, the first and second network elements generate link failure indications including time values representing when the respective network element detected the fault. In other embodiments, the link failure indications include time values transmitted over the communications link between the first and second network elements. A time distance between these time values is calculated, which is used to calculate the estimated physical location of the fault. In some embodiments, the link failure indications include sequence numbers transmitted or about to be transmitted over the communications link between the network elements. Sequence distances are calculated between the sequence numbers, and are used to calculate the estimated physical location of the fault.

Time-based link fault localization

An access subnetwork node herein comprises one or more add-drop modules, each module including one or more passive optical filters. The one or more add-drop modules are configured to selectively drop a fixed band of wavelength channels from an access subnetwork, via a passive directional coupler, to each of multiple client nodes that actively select to receive client-specific channels within the fixed band. The one or more add-drop modules are also configured to selectively add the fixed band of wavelength channels to the access subnetwork, as received via a passive directional coupler from the multiple client nodes that actively select to transmit client-specific channels within the fixed band. With an access subnetwork node and a client node configured in this way, embodiments herein reduce the complexity and accompanying cost of nodes in an optical network, while also maintaining flexibility for assigning wavelength channels in the network.

Methods and apparatus for a passive access subnetwork

Embodiments of the present invention relate system and method for handling large dynamical signals in a passive optical network system and in particular for determining scheduling of bursts from a plurality of optical network units. More particularly, embodiments of the present invention relate to a system and method for determining a bit error ratio, i.e. BER in received communication data, determining, using the BER, optimized transmission scheduling of communication bursts from the optical network units, and providing a signal to the optical network units indicating the transmission scheduling of transmission bursts in accordance with the determined optimized transmission scheduling.

Overhead adjustment scheme for passive optical networks

Sequence-based link fault localization

A method and apparatus for controlling DC balance in a digital communication system in which data frames are transmitted, wherein the data frames include a header portion that is transmitted unscrambled and a payload portion that is scrambled before transmission. The header portion includes a frame counter field. A value for the frame counter field is randomly generated and an effect on the DC balance is estimated. It is then determined whether the estimated effect on the DC balance meets defined requirements for DC balance. When the estimated effect does not meet the defined requirements for DC balance, a new random value for the frame counter field is generated and checked. When the estimated effect meets the requirements, the randomly generated value is utilized in the frame counter field in transmitted data frames.

Method and apparatus providing protection and DC balance in a communication system

A control device () for scheduling the transmission of signals from a plurality of transmitters (). The control device () comprises an evaluation element () arranged to determine the power level of the signals received from each of the transmitters and a scheduling element () adapted to determine a transmit schedule comprising the order that the plurality of transmitters should transmit based on the power levels of the signals received from the transmitters (). A method of operation and a node incorporating the control device is also disclosed.

Scheduling device

A hub node in a wavelength division multiplexed optical network automatically discovers at least one of new client-side optical ports and new edge-side optical ports. The hub node comprises a wavelength switch network, port discovery equipment, and a controller. The wavelength switch network routes any wavelength channel that does not support a matching pair of client-side and edge-side ports to port discovery equipment at the hub node. The port discovery equipment searches for new ports, and, responsive to finding a new port, automatically discovers a predefined set of one or more attributes of the new port. The controller determines that a client-side port and an edge-side port are a matching pair of ports if discovered sets of attributes of those ports match according to one or more predefined rules. The controller then controls the wavelength switch network to re-route the wavelength channel supporting that matching pair between those ports.

Optical port discovery in a WDM optical network

A wavelength-multiplexed passive optical network (WDM-PON) and a method are described herein for setting-up (e.g., wavelength tuning, power tuning) an ONT laser by establishing a communications channel on an optical layer between an optical line terminal (OLT) and an optical network termination (ONT). The communications channel is established by utilizing the OLT's laser shutdown function and the ONT's signal detection function.

WDM-PON system, ONT, OLT and method for initialization of tunable laser

An optical network unit for a passive optical network (), configured to: initiate an upstream wavelength (w) for an upstream signal (US) from the optical network unit to an optical line terminal (); iteratively, until an iteration criterion is met, i) transmit the upstream signal (US) to the optical line terminal (), ii) receive from the optical line terminal () power level data (p) for the upstream signal (US) as measured by the optical line terminal (), and iii) set the upstream wavelength (w) for the upstream signal (US) to a new wavelength-value; and adjust the upstream wavelength (w) to a wavelength-value previously set for the upstream signal (US) and associated with power level data corresponding to a certain power level. A passive optical network system, the optical line terminal and related methods are also disclosed.

Methods and devices for wavelength alignment in WDM-PON

A threshold value is set in a decision circuit receiving a transmitted stream of binary symbols from a network link. The decision circuit uses the threshold value for detecting whether a 1 or a 0 is received to produce an output stream having a low bit error rate. Bit errors in the output stream of the detector are detected. The number of errors is counted when a transmitted 0 is detected as a 1 in the output stream. The number of errors is also counted when a transmittedis detected as a 0 in the output stream. The counted numbers of errors are compared to each other. The threshold value is modified, if necessary, based on the result of the comparing, to e.g. make the probabilities of the two kinds of errors equal to each other. Extra predetermined bits can be inserted and used in determining bit errors.

Growing community of inventors

Stockholm, Sweden

Peter Öhlén