Abstract: A method comprising: from an optical network, receiving estimates of accumulated chromatic dispersion of an optical signal or a rate of change of said accumulated chromatic dispersion, the estimates being indicative of measurements at a coherent optical receiver on the optical signal received from an optical link of the optical network at corresponding times; from the optical network, receiving measurements of optical link performance made at the coherent optical receiver in response to recovering data carried by the received optical signal; and identifying at least one of the measurements of optical link performance as being unreliable in response to determining that the estimates indicate the accumulated chromatic dispersion of the optical signal varied at an above threshold rate near a time corresponding to said at least one of the measurements of optical link performance.

Abstract: The present invention provides a method for controlling transmission of a signal between a transmitter and a receiver during a phase of change of a signal data rate. The method comprises, when the change is requested, informing the transmitter and receiver of a start of a transition phase. The transmitter retransmits the signal N times, with N?1, in identical signal parts having a chosen length. The receiver stores the N retransmitted identical signal parts successively received to combine them together to produce a combined signal part, and to temporarily output these combined signal parts with an auxiliary data rate depending on N and on this signal part length. The transmitter and the receiver are informed of the end of the transition phase when the signal data rate change is finished.

Abstract: The present invention provides a method for controlling transmission of a signal between a transmitter and a receiver during a phase of change of a signal data rate. The method comprises, when the change is requested, informing the transmitter and receiver of a start of a transition phase. The transmitter retransmits the signal N times, with N?1, in identical signal parts having a chosen length. The receiver stores the N retransmitted identical signal parts successively received to combine them together to produce a combined signal part, and to temporarily output these combined signal parts with an auxiliary data rate depending on N and on this signal part length. The transmitter and the receiver are informed of the end of the transition phase when the signal data rate change is finished.

Abstract: A technique is provided for modulating light in a telecommunication network. The technique includes modulating light with a first intensity modulator and modulating light with a second intensity modulator. The first intensity modulator and the second intensity modulator are applied a mutual angular phase shift. The mutual angular phase shift is non-orthogonal and non-PI/2-dividable.

Abstract: An apparatus, a method and a computer program for determining estimates is disclosed. The apparatus determines estimates for transmitted symbols from received symbols of an optical signal affected by cross-Polarization Modulation (XpolM). The apparatus groups two or more subsequent received symbols from the optical signal into a group of received symbols and estimates an optical channel based on the group of received symbols and a hypothesis on the transmitted symbols. The apparatus further determines a reliability measure for a combination of the group of received symbols, the channel estimate, and the hypothesis, and determines the estimates for the transmitted symbols based on reliability measures for multiple hypotheses on the transmitted symbols.

Abstract: An apparatus, a method and a computer program for determining estimates is disclosed. The apparatus determines estimates for transmitted symbols from received symbols of an optical signal affected by cross-Polarization Modulation (XpolM). The apparatus groups two or more subsequent received symbols from the optical signal into a group of received symbols and estimates an optical channel based on the group of received symbols and a hypothesis on the transmitted symbols. The apparatus further determines a reliability measure for a combination of the group of received symbols, the channel estimate, and the hypothesis, and determines the estimates for the transmitted symbols based on reliability measures for multiple hypotheses on the transmitted symbols.

Abstract: A method and apparatus are provided for emitting and receiving a signal in a multi-antennae system, using spatial precoding. A method for emitting a signal from an emitter towards a receiver via a transmission channel, in the form of a set of data flows, includes distributing the emission antennae into a plurality of groups containing at least one antenna, at least one group containing two antennae, according to at least one piece of information representing the transmission channel. The method also includes: attributing an efficiency to each emission antenna; allocating an emission power to each data flow; and spatial precoding the signal, using a matrix for diagonal precoding by blocks, containing at least two blocks, each block being associated with one of the groups of antennae.

Abstract: A method is provided for receiving a signal, corresponding to a data signal transmitted by a transmitter to a receiver via a transmission channel. The method includes the following steps: analyzing the signal received, delivering an information item representative of the transmission channel; determining, periodically and/or as a function of a variation of the transmission channel: at least one distribution of the transmission antennas into at least one group of at least one antenna as a function of the information item representative of the transmission channel, wherein at least one group includes at least two transmission antennas for at least one of the determinations; and specific efficiencies assigned respectively to each of the groups of antennas for each distribution as a function of the information item, and transmitting to the transmitter a parameterization signal defining the at least one distribution and the specific efficiencies.

Abstract: A method and apparatus are provided for emitting and receiving a signal in a multi-antennae system, using spatial precoding. A method for emitting a signal from an emitter towards a receiver via a transmission channel, in the form of a set of data flows, includes distributing the emission antennae into a plurality of groups containing at least one antenna, at least one group containing two antennae, according to at least one piece of information representing the transmission channel. The method also includes: attributing an efficiency to each emission antenna; allocating an emission power to each data flow; and spatial precoding the signal, using a matrix for diagonal precoding by blocks, containing at least two blocks, each block being associated with one of the groups of antennae.

Abstract: A method is provided for receiving a signal, corresponding to a data signal transmitted by a transmitter to a receiver via a transmission channel. The method includes the following steps: analyzing the signal received, delivering an information item representative of the transmission channel; determining, periodically and/or as a function of a variation of the transmission channel: at least one distribution of the transmission antennas into at least one group of at least one antenna as a function of the information item representative of the transmission channel, wherein at least one group includes at least two transmission antennas for at least one of the determinations; and specific efficiencies assigned respectively to each of the groups of antennas for each distribution as a function of the information item, and transmitting to the transmitter a parameterization signal defining the at least one distribution and the specific efficiencies.