Telefonaktiebolaget Lm Ericsson (publ)

Optis Cellular Technology, LLC

Chunlong Bai

Bo Göransson

Bradley John Morris

Chunyun Jian

Sai Mohan Kilambi

Edward Sich

Brian Lehman

Yuxing Zhang

John Bradley Morris

A multi-bit HARQ feedback is transmitted by a receiver to a transmitter. The multi-bit feedback is a function of a level of convergence reached by a decoder when the previously transmitted coded data bits were decoded. The transmitter is configured to select a set of coded data bits for a retransmission as a function of the multi-bit feedback. In some embodiments, different redundancy versions of the coded data bits may be selected as a function of the multi-bit feedback. In other embodiments, a bit puncturing or bit repetition pattern may be selected as a function of the multi-bit feedback.

Hybrid automatic repeat request with feedback dependent bit selection

Systems and methods for compensating for non-linearity of a non-linear subsystem using predistortion are disclosed. In one embodiment, a system includes a non-linear subsystem and a predistorter configured to effect predistortion of an input signal of the non-linear subsystem such that the predistortion compensates for a non-linear characteristic of the non-linear subsystem. In addition, the system includes a narrowband filter that filters a feedback signal that is representative of an output signal of the non-linear subsystem to provide a filtered feedback signal, and an adaptor that adaptively configures the predistorter based on the filtered feedback signal and a reference signal that is representative of an input signal of the non-linear subsystem. By utilizing the filtered feedback signal, rather than the feedback signal, a complexity, and therefore, cost of the adaptor is substantially reduced.

Architecture of a low bandwidth predistortion system for non-linear RF components

Systems and methods for compensating for a non-linear characteristic of a non-linear filter in a transmit chain of a transmitter using predistortion are disclosed. In one embodiment, a transmitter includes a power amplifier configured to amplify a radio frequency input signal to provide an amplified radio frequency signal, a non-linear filter configured to filter the amplified radio frequency signal to provide an output signal of the transmitter, and a predistorter configured effect predistortion of the amplified radio frequency signal, where the predistortion compensates for a non-linear characteristic of the non-linear filter. In this manner, the output signal is as if the non-linear filter were a linear, or substantially liner, filter. The predistortion applied by the predistorter may be fixed or adaptive.

Architecture of nonlinear RF filter-based transmitter

Methods and apparatus are disclosed for compressing and decompressing data to reduce bandwidth requirements in transmissions of predistorted signals between a processing node and a remote transmitting node of a power amplifier with digital predistortion (PA-DPD) system. In the processing node, predistorted signals are decomposed into a high-dynamic range signal of a first sample rate and a low-dynamic range signal of a second sample rate greater than the first sample rate. Samples of both signals are combined to generate a compressed signal for transmission to the remote transmitting node, which decompresses the compressed signal to restore the predistorted signal.

Method of transmitting data samples with reduced bandwidth

A multi-bit HARQ feedback is transmitted by a receiver to a transmitter. The multi-bit feedback is a function of a level of convergence reached by a decoder when the previously transmitted coded data bits bit were decoded. The transmitter is configured to select a set of coded data bits for a retransmission as a function of the multi-bit feedback. In some embodiments, different redundancy versions of the coded data bits may be selected as a function of the multi-bit feedback. In other embodiments, a bit puncturing or bit repetition pattern may be selected as a function of the multi-bit feedback.

Hybrid automatic repeat request with feedback dependent BIT selection

Systems and methods are disclosed for effecting predistortion of a concurrent multi-band signal to compensate for power amplifier non-linearity. In general, the concurrent multi-band signal contains frequency components occupying multiple frequency bands with no frequency components between adjacent frequency bands. In one embodiment, a transmitter includes a power amplifier that amplifies a modulated concurrent multi-band signal to provide an amplified concurrent multi-band signal. A predistortion sub-system effects predistortion of the modulated concurrent multi-band signal prior to amplification in order to compensate for non-linearity of the power amplifier. The predistortion sub-system includes a number of predistorters each providing predistortion for a different one of the frequency bands of the modulated concurrent multi-band signal. At least one of the predistorters provides predistortion for the corresponding frequency band of the modulated concurrent multi-band signal based on carrier frequency information for the modulated concurrent multi-band signal.

Predistortion of concurrent multi-band signal to compensate for PA non-linearity

Embodiments include a method for predistorting an input signal at a predistorter to compensate for distortion introduced by a non-linear electronic device operating on the input signal to produce an output signal. The method entails generating first and second signal samples for each of a plurality of sampling time instances. The first and second signal samples represent the input and output signals, and are spaced at unit-delay intervals. The method further entails calculating, from the first and second signal samples, parameters for an ANN-based model. The ANN-based model includes a tapped delay line configured to dynamically model memory effects of the distortion introduced by the device, or of the response of the predistorter, with a multi-unit delay interval between at least one pair of adjacent delays. The method also includes predistorting the input signal according to the ANN-based model, to produce a predistorted input signal for input to the device.

Predistortion according to an artificial neural network (ANN)-based model

A method and apparatus for memory modeling in a pre-distortion architecture are disclosed. In one embodiment, a memory model has a plurality of branches. Each branch receives a different output basis function signal. Each branch includes at least one delay element. Each delay element causes a pre-determined delay of the output basis function signal received by the branch. The amount of a pre-determined delay is different for each of at least two branches.

Memory structure having taps and non-unitary delays between taps

Disclosed is a signal splitting apparatus useable in a power amplifier having two or more power amplifiers. The apparatus includes a direct gain component; and a derived gain component connected to the direct gain component. The derived gain component derives the derived gain by imposing a constraint which is valid over the entire dynamic range of the input signal, e.g. the sum of the power of the direct split signal and the derived split signal are constrained to be substantially equal to the power of the input signal. The use of combining additional direct gain and derived gain components, as well as a delay element, are disclosed so as to enable n-component splitting that for adaptation to different applications by the use of suitable coefficients.

Signal splitting apparatus suitable for use in a power amplifier

Systems and methods are disclosed for compensating for non-linearity of a power amplifier using space mapping based predistortion. In one embodiment, a transmitter includes a power amplifier that amplifies a power amplifier input signal, a predistorter that effects predistortion of the power amplifier input signal to compensate for a non-linear characteristic of the power amplifier using a space mapping based model of an inverse of the non-linear characteristic of the power amplifier, and an adaptation sub-system that adaptively configures the space mapping based model of the non-linear characteristic of the power amplifier. In one embodiment, the adaptation sub-system adaptively configures a space mapping based model of the non-linear characteristic of the power amplifier and adaptively configures the space mapping based model of the inverse of the non-linear characteristic of the power amplifier based on the space mapping based model of the non-linear characteristic of the power amplifier.

Architecture and the training method of a PA DPD system with space mapping applied in the predistorter

The present disclosure generally relates to predistortion that compensates for non-linearity of a power amplifier as well as short-term and long-term memory effects of the power amplifier. In one embodiment, a transmitter includes a power amplifier that amplifies a power amplifier input signal to provide a power amplifier output signal, a predistortion sub-system that effects predistortion of the power amplifier input signal to compensate for non-linearity of the power amplifier and memory effects of the power amplifier, and a adaptation sub-system that adaptively configures the predistortion sub-system. The predistortion sub-system includes a memory-less predistortion component that compensates for the non-linearity of the power amplifier, a Finite Impulse Response (FIR) filter that compensates for short-term memory effects of the power amplifier, and an Infinite Impulse Response (IIR) filter that compensates for long-term memory effects of the power amplifier.

FIR/IIR filter predistorter for power amplifiers exhibiting short-term and/or long-term memory effects

Methods and apparatus are disclosed for predistorting an input signal to compensate for non-linear distortions introduced by an electronic device, for example, a power amplifier. The non-linear effects of a power amplifier can be modeled using different behavior models. Coefficients for one behavior model can be converted into coefficients for a different behavior model using a conversion function. A conversion circuit implementing the conversion function can be used in between a predistorter and an adaptation circuit that use different models.

Modeling digital predistorter

Hybrid Automatic Repeat Request (HARQ) is implemented using multi-bit feedback and variable retransmission energy. The multi-bit feedback provides information to the transmitter about the state of the decoder so that the transmitter can adapt retransmissions to the current state of the decoder. In some embodiments, the multi-bit feedback indicates a level of convergence reached by the decoder, and the transmitter varies an amount of energy used for the retransmission as a function of the multi-bit feedback. The transmitter can vary the amount of energy applied to the retransmission by varying the number of bits in the retransmission, or by varying a transmit power used for the retransmission.

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Kanata, Canada

Chunlong Bai