Telefonaktiebolaget Lm Ericsson (Publ)

János Ladvánszky

Benedek Kovács

Gabor Kovacs

Boris Dortschy

Anna Rhodin

Martin Dahlström

Tamas Szili

Mats Göran Wilhelmsson

A demodulation system for demodulating an input signal is provided. The input signal includes a carrier wave modulated with data symbols selected from a plurality of candidate complex symbol values. The system includes a carrier recovery module, operative to compensate for a carrier frequency of the carrier wave and output a demodulated data signal. The carrier recovery module includes: a first complex-signal conversion module, operative to convert the input signal into a complex-valued input signal; a voltage-controlled oscillator; a mixer, for mixing the complex-valued input signal and a complex-valued output signal of the voltage-controlled oscillator, and generating a mixer output signal; a low-pass filter, coupled to the mixer, operative to filter the carrier frequency from the mixer output signal, and output a signal corresponding to the demodulated data signal; and a folding module, operative to apply a folding algorithm to the output signal of the low-pass filter.

Methods and apparatus for signal demodulation

A technique for transmitting data is described. The data is represented by a modulation symbol comprising an in-phase component and a quadrature component. Considering a method aspect of the technique, the modulation symbol () is split into at least two different baseband signals (), which are in phase with each other and jointly representative of the modulation symbol (). The at least two baseband signals () are up-converted from a baseband frequency to a transmission frequency. Each of the at least two up-converted signals () is transmitted on a different physical channel ().

Technique for coherent data communication

A technique for performing data modulation is described. As to a method aspect of the technique, n bits of data are mapped to one modulation symbol () out of a modulation alphabet comprising 2modulation symbols (). The modulation alphabet corresponds to a finite subset of a hexagonal lattice in a constellation plane () spanned by an in-phase value () and a quadrature value () of a signal. All modulation symbols () are spaced apart in the constellation plane () from a direct current, DC, component corresponding to zero in-phase value and zero quadrature value. The signal corresponding to the mapped modulation symbol () is output.

Digital modulation technique

The present invention relates to methods for controlling a multi-channel power supply and to corresponding devices. According to one embodiment of the invention, a method for controlling a multi-channel power supply is provided. Therein each channel comprises an intrinsic channel resistance and a resistor adjustable between a lowest resistance and a highest resistance. The method comprises the following steps: Measuring for each channel a measure indicative of a current in the respective channel; Adjusting, on the basis of the measures, the adjustable resistor in the channel having the highest intrinsic channel resistance to the lowest resistance; and Adjusting, on the basis of the measures, the adjustable resistor(s) in the remaining channel(s), such that currents in each channel are balanced. With it a concept of simultaneously performing current balancing and reduction of power dissipation is provided.

Controlling a multi-channel power supply

A device for linearizing non-linear signal transmission characteristics of an optical communication system. A non-linearity introducing part is between an input port and an output port of the optical communication system. The non-linearity introducing part at least partly causes said non-linear signal transmission characteristics. The device is configured for connection between said input port and the non-linearity introducing part, in parallel with the non-linearity introducing part, and comprises a pair of Junction Field Effect Transistors (JFETs), configured to operate in an anti-parallel configuration.

Optical communication system and device for linearizing non-linear signal transmission characteristics

The present invention relates to a receiver in a 2&#xd7;2 Line of Sight Multiple Input Multiple Output, LoS MIMO, system. The receiver is arranged to estimate a first (&#x15c;) and a second (&#x15c;) signal on the basis of a first (r(t)) and a second (r(t)) signal received from respective first and second transmitters (Tx,Tx). Said received signals (r(t), r(t) comprises a first and second signal. The receiver comprises a first Phase Locked Loop (), PLL, and a second PLL (), which are arranged to respectively determine a first (In) and second (In) demodulated signal from the first (r(t)) and the second (r(t)) received signals. The receiver further comprises an equalizer () which is arranged to estimate the first (&#x15c;) and second (&#x15c;) signals from the demodulated signals (In,In). The receiver is particularly characterized in that the equalizer () further is arranged to compensate for an independent rotation frequency ftrftr, where ftrand ftrare the respective deviations from the nominal frequency values of a first and a second transmitted signals comprising the first and second signals.

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Pomaz, Hungary

János Ladvánszky