Institut Mines-telecom / Telecom Bretagne

Institut Mines Telecom-imt Atlantique-bretagne-pays De La Loire

Institut Mines-telecom

Institut Mines-telecom / Telecom

Jérémy Nadal

Charbel Abdel Nour

Amer Baghdadi

A device configured to perform a stage of circular convolutions in an Overlap-Save Filtered-Bank Multicarrier Communication (OS-FBMC) or Overlap-Save-Block FBMC (OSB-FBMC) receiver and the corresponding method, the stage of circular convolutions comprising P circular convolutions operated between subsets of input samples and frequency domain responses of a frequency shifted version of a prototype filter associated to an FBMC modulation having Ccoefficients, with P an integer greater than one, the device comprising at least one Finite Impulse Response filter implemented in the form of a transposed direct filter having at least C−1 taps numbered p=−Δ+1 to p=Δ with wherein the multiplier coefficient of each tap p within the set of taps−Δ+1; 0has an equal absolute value to the multiplier coefficient of tap (1−p). An FBMC equalization and demodulation unit or an FBMC receiver comprising the device.

Optimised circular convolutions stage for OS/OSB FBMC receivers

A method and device to modulate an FBMC/OQAM signal, the device comprising at least one QAM mapper mapping a binary stream into complex symbols, a first and a second transmission chain. Each chain comprises: a precoder transposing respective sets of symbols into frequency domain real/imaginary samples, a phase rotator applying a phase quadrature keying to said samples, an FBMC modulator to modulate the output of the phase rotator into an FBMC symbol. The device further comprises an adder of the output of the first transmission chain with a delayed output of the second transmission chain, and is configured to insert guard interval sequences into the binary stream or into the symbols processed by the precoders. A corresponding radio communication equipment, computer program and readable medium is provided.

Pseudo-guard intervals insertion in an FBMC transmitter

An FBMC equalization and demodulation unit and corresponding method to process an FBMC signal includes FBMC symbols, each FBMC symbol comprising data mapped over M subcarriers, oversampled by a factor K, filtered by a prototype filter and transposed in the time-domain, comprising: a frequency domain transposition unit, configured to transpose a block of P*KM samples comprising at least one FBMC symbol into frequency domain samples, where P is an integer greater than one, an equalizer unit configured to multiply the frequency domain samples by one or more coefficients computed from a propagation channel estimate, at least one circular convolution unit, configured to perform P circular convolutions between subsets of the equalized samples and a frequency domain response of a frequency shifted version of the prototype filter, and adders, to sum corresponding outputs of each of the P circular convolutions.

Overlap-save FBMC receiver

An encoder architecture for UF-OFDM is provided, in which samples are first processed sub-band wise, and then resorted for sub-carrier-wise processing. The sub-carrier processing may comprise separate processing for the two extremity parts of the base band signal corresponding to the transient state of the UF-OFDM data stream and for a core part of the base band signal corresponding to the non-transient state of the UF-OFDM data stream, and then concatenated to obtain a UF-OFDM data stream. In certain embodiments a first extremity part of the base band signal corresponding to the transient state of the UF-OFDM data stream is calculated directly, and the other extremity part inferred from the core part and the first extremity part. The core and extremity part processors may be implemented with filters adapted to multiply each sample by a respective filter coefficient. Modifying these coefficients can introduce a frequency shift or convert the encoder for OFDM encoding.

Digital encoder and method of encoding

A receiver for Filter Bank Multicarrier frequency spread signals such as FBMC, FBMC/OQAM, OFDM, comprises a linear phase rotation module adapted to introduce a linear phase rotation to a received time domain signal, a discrete Fourier transform and a Finite Impulse response digital filter. The coefficients of the digital filter define a shift of the frequency response of the prototype filter of the receiver, and the coefficients of the digital filter are fixed so as to compensate the linear phase rotation introduced by the filter. The frequency shift introduced may be equal to the reciprocal of a power of two of the modulation sub carrier spacing.

Receiver architecture for linear modulation based communication systems

A method of designing a digital filter for example for use in an FBMC/OQAM telecommunications system, with a target overlapping factor and meeting a specified signal to interference ratio is described, whereby a candidate filter design defined by an impulse response, satisfying the Nyquist criterion and having an overlapping factor higher than the target is selected, and the time and frequency coefficients of its impulse response inverted to define a new filter design; and truncating the impulse response defining said new filter design to the minimum number of coefficients achieving said specified signal to interference ratio.

Growing community of inventors

Brest, France

Jérémy Nadal