Telefonaktiebolaget Lm Ericsson (publ)

Ciena Corporation

Intel Corporation

Applied Micro Circuits Corporation

Mark Edward Rollins

Pierre-Andre Laporte

Daniel J Pugh

Andrew Deczky

Bilel Fehri

Kim Bryon Roberts

Shahab Oveis Gharan

John Duncan McNicol

James St Harley

Mark William Wyville

Arthur Thomas Gerald Fuller

Christian Bourget

Douglas McGhan

Arthur T G Fuller

Haiying Cao

Systems and methods are disclosed herein that relate to Peak-to-Average Power Ratio (PAPR) reduction in a MIMO OFDM transmitter system. In some embodiments, a method of operation of a transmitter system includes, for each carrier of two or more carriers, performing precoding of frequency-domain input signals for the carrier to provide frequency-domain precoded signals for the carrier, the frequency-domain input signals for the carrier being for a plurality of transmit layers for the carrier, respectively. The method further includes processing the two or more pluralities of frequency-domain precoded signals for the two or more carriers, respectively, in accordance with a multi-carrier processing scheme to provide a plurality of multi-carrier time-domain transmit signals for a plurality of antenna branches, respectively, of the MIMO OFDM transmitter system. The multi-carrier processing scheme provides PAPR reduction for Cyclic Prefixes (CPs) of the plurality of multi-carrier time-domain transmit signals for the plurality of antenna branches.

Systems and methods for multi-carrier or multi-band low-PAPR precoding that handle cyclic prefix

Systems and methods for multi-carrier or multiband low-PAPR precoding that handle cyclic prefix

A method and apparatus for artificial neural network precoding for massive MIMO systems are disclosed. In one embodiment, a method includes processing, by an artificial neural network, ANN, precoding engine, at least one input signal by 5 performing a low peak-to-average-power ratio, PAPR, precoding on the at least one input signal; and transmitting, via at least one antenna array having at least one antenna, at least one precoded output signal processed by the ANN precoding engine.

Artificial neutral network precoding for massive MIMO systems

Systems and methods are disclosed herein for selectively compensating for a specific Intermodulation Distortion (IMO) product(s) of an arbitrary order in a transmitter system. In some embodiments, a method of compensating for one or more specific IMO products in a concurrent multi-band transmitter system comprises generating an IMO correction signal for a specific IMO product as a function of two or more frequency band input signals for two or more frequency bands of a concurrent multi-band signal, the IMO product being an arbitrary order IMD product. The method further comprises frequency translating the IMD correction signal to a desired frequency that corresponds to a Radio Frequency (RF) location of the specific IMO product and, after frequency translating the IMO correction signal to the desired frequency, utilizing the IMO correction signal to compensate for the specific IMO product.

Correction of specific intermodulation products in a concurrent multi-band system

Systems and methods are disclosed herein that related to Peak-to-Average Power Ratio (PAPR) reduction in a (e.g., massive) Multiple-Input Multiple-Output (MIMO) Orthogonal Division Multiplexing (OFDM) transmitter system. In some embodiments, a method of operation of a MIMO OFDM transmitter system comprises, for each carrier of two or more carriers, performing precoding of a plurality of frequency-domain input signals for the carrier to provide a plurality of frequency-domain precoded signals for the carrier, the plurality of frequency-domain input signals for the carrier being for a plurality of transmit layers for the carrier, respectively. The method further comprises processing the frequency-domain precoded signals for the two or more carriers in accordance with a multi-carrier Convex Reduction of Amplitudes (CRAM) processing scheme to provide a plurality of multi-carrier time-domain transmit signals for a plurality of antenna branches, respectively, of the MIMO OFDM transmitter system.

Convex reduction of amplitudes for OFDM MIMO with multiple carriers

A method and system for digital pre-distortion of an input signal to compensate for non-linear operation of a power amplifier. According to one aspect, some embodiments provide overlapping spline functions that are defined for two adjacent bins, where any two spline functions overlap in only one bin. Each spline function is computed as a function of one of an input signal envelope and a delayed signal envelope. According to another aspect, a tap weight evaluator includes a least mean squares, LMS, tap correlator updater configured to modulate a step size of an adaptation process to update each tap weight, the step size being modulated based on an approximate logarithm of the average power of the input to a tap weight computation.

Least mean squares adaptation of a concurrent multi-band pre-distorter using overlapping spines

Systems and methods for radio frequency digital predistortion in a multi-band transmitter are disclosed. In one embodiment, the multi-band transmitter includes a digital upconversion system configured to digitally upconvert digital input signals to provide digital radio frequency signals. Each digital input signal and thus each digital radio frequency signal corresponds to a different band of a multi-band transmit signal to be transmitted by the multi-band transmitter. The multi-band transmitter also includes a radio frequency digital predistortion system configured to digitally predistort the digital radio frequency signals to provide predistorted digital radio frequency signals, and a combiner configured to combine the predistorted digital radio frequency signals to provide a multi-band predistorted digital radio frequency signal.

Multi-band radio-frequency digital predistortion

Systems and methods are disclosed for digital predistortion for a concurrent multi-band transmitter that compensates for both in-band and out-of-band intermodulation products according to a memory polynomial based baseband model. In one embodiment, a concurrent multi-band transmitter includes a digital predistortion subsystem, power amplifier circuitry, and an adaptation subsystem. The digital predistortion subsystem includes multiple digital predistorters configured to process digital input signals for frequency bands of a concurrent multi-band signal to provide predistorted digital input signals each being for a different one of the frequency bands of the concurrent multi-band signal and one or more intermodulation distortion compensation signals each being for a different one of one or more intermodulation distortion frequency bands. The adaptation subsystem is configured to adaptively configure the plurality of digital predistorters according to a memory polynomial based digital baseband model of the digital predistorters.

Linearization of intermodulation bands for concurrent dual-band power amplifiers

A transmitter in an optical communications system includes a digital signal processor for processing a data signal to generate a sample stream encoding successive symbols in accordance with a constrained phase modulation scheme having a constellation of at least two symbols and a modulation phase constrained to a phase range spanning less than 4&#x3c0;. A digital-to-analog converter converts the sample stream into a corresponding analog drive signal. A finite range phase modulator modulates a phase of a continuous wavelength channel light in accordance with the analog drive signal, to generate a modulated channel light for transmission through the optical communications system. A receiver in the optical communications system includes an optical stage for detecting phase and amplitude of the modulated channel light and for generating a corresponding sample stream, and a digital signal processor for processing the sample stream to estimate each successive symbol of the modulated channel light.

Constrained continuous phase modulation and demodulation in an optical communications system

The present disclosure provides timing recovery in optical systems in the presence of chromatic dispersion (CD), polarization mode dispersion (PMD), and polarization dependent loss (PDL) and to optimization of equalization settings based upon timing recovery moment strengths. A stable timing point may be determined in the presence of PMD and PDL impairments, even when the direct estimate of timing becomes unreliable. This determination may be performed entirely in the digital domain providing precise, predictable performance. Also, the present invention utilizes a monotonic relationship between the timing metric and CD setting error to provide directed search in setting the CD equalizer thereby reducing significantly the overall search effort in optimizing CD equalizer settings. This utilizes computations already performed by the transceiver for timing recovery function yielding a computational advantage over competing methods.

Timing recovery in presence of optical impairments and optimization of equalization based on timing recovery moment strengths

The present disclosure relates to coherent optical receiver systems and methods for determining and correcting for optical angle and magnitude imbalance and for delay imbalance between quadrature paths. The present invention iteratively determines and corrects imbalance error and differential delay entirely in the digital domain (after an analog to digital conversion) in the presence of all the other impairments (polarization mode dispersion, chromatic dispersion, polarization gain imbalance, and polarization delay imbalance) using only the corrupted received signal during normal operation, i.e. without the use of training data. The present invention provides an effective adaptive scheme to drive impairments to zero, without using of any calibration of training, and may be applied during normal operation of the receiver via electrical circuitry or the like.

Coherent optical receiver systems and methods

Conventional adaptive equalizers often use the 'sign/sign' algorithm as a low complexity means to adjust their tap weight coefficients by driving the correlation between its single-bit 'error' and &#x201c;data&#x201d; signals to zero. This algorithm fails in the presence of strong residual intersymbol interference (ISI), since this ISI renders the &#x201c;error&#x201d; signal sufficiently inaccurate to mask the correlation between &#x201c;data&#x201d; and &#x201c;error&#x201d;. Failure manifests itself two-fold as an inability to achieve tap weight acquisition at startup, and an inability to track dynamic channel conditions. The invention described herein employs an adaptive estimator to compute the residual masking ISI terms that in turn control an adaptive error slicer to synthesize a modified single-bit &#x201c;error&#x201d; signal that remains correlated with the &#x201c;data&#x201d; signal. By restoring this correlation between &#x201c;error&#x201d; and &#x201c;data&#x201d; using these two modifications, the &#x201c;sign/sign&#x201d; algorithm retains its acquisition and tracking capabilities in the presence of strong residual ISI.

Adaptive error slicer and residual intersymbol interference estimator

A gold code generator is described comprising two pairs of linear feedback shift registers, the seed values for the second pair of linear feedback shift registers are different from the seed values for the first pair of linear feedback shift registers. The second seed values are calculated from the first seed values. The use of this second pair of linear feedback shift registers prevents the need to use a wide span of taps to the linear feedback shift register to produce output bits. By using two pairs of linear feedback shift registers, a parallel output implementation can be produced in which multiple output bits are produced in a single clock cycle.

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Stittsville, Canada

Mark Edward Rollins