Nortel Networks Corporation

Apple Inc.

Microsoft Technology Licensing, LLC

Blackberry Corporation

Telefonaktiebolaget Lm Ericsson (publ)

Research in Motion Corporation

Future Wei Technologies, Inc.

Arthur Thomas Gerald Fuller

Bradley John Morris

Mark Edward Rollins

Russell Smiley

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

A receiver and method is provided for sigma-delta converting an RF signal to a digital signal and downconverting to a digital baseband signal. The RF signal is split into N phases, as can be accomplished using a sample and hold circuit, and each phase is digitized, as can be accomplished using an analog-to-digital (A/D) sigma-delta converter. Polyphase decimation techniques and demodulation are applied to the phased signals to generate a demodulated digital signal. The demodulated digital signal is further downconverted to the appropriate baseband signal.

Digital receiver

A communication system comprising signal processing circuitry and up-conversion circuitry. The signal processing circuitry is configured to: i) generate a first signal of a first modulation type and a second signal of a second modulation type; ii) combine the first and second signals to form a combined input signal; iii) generate peak reduction distortion based on the combined input signal; iv) select a portion of the peak reduction distortion that corresponds to a first frequency band; and v) apply the selected portion of the peak reduction distortion in the first frequency band of the combined input signal to provide a combined output signal. The up-conversion circuitry up-converts the combined output signal to an RF signal for transmission.

Selective peak power reduction

Methods and apparatus are described herein that make use of complex tuning, the inherently repetitive nature of sampled signals, and programmable digital filtering to create a flexible digital up-conversion system that utilizes a digital-to-analog converter (DAC) with a fixed effective sample rate while still being adapted for tunability over a wide frequency range. With a knowledge of the fixed effective sample rate of the DAC and a desired frequency of up-conversion and combining complex tuning at baseband and up-sampling by a factor of N with a programmable passband filter configured to select one of a plurality of signal images resulting from the up-sampling, it is possible to translate a baseband input signal to a wide range of frequencies above or below F, without changing the sampling rate of the fixed rate DAC used in the up-conversion process.

Methods and systems for programmable digital up-conversion

Digital receiver and method

Systems and methods are disclosed that include selecting a sampling frequency and a tuning resolution frequency. These systems and methods may further include determining a wordlength of the phase accumulator, a numeric representation of the phase range, and a reduced representable value of a phase accumulator. In addition, these systems and methods may include operating the phase accumulator, where the phase accumulator creates an output phase accumulator signal. These systems and methods may further includes adjusting the angle of the output phase accumulator signal, where the output phase accumulator signal is adjusted based upon the operation of the phase accumulator, where adjusting the angle of the output phase accumulator signal creates an adjusted output phase accumulator signal and operating a CORDIC module, and where the CORDIC module performs operations upon the output phase accumulator signal based upon the parameters of the phase accumulator.

CORDIC based complex tuner with exact frequency resolution

In an embodiment, a system for multi-band predistortion has a predistortion actuator applying a first and a further adjustable distortion to a first band input and at least one further band input, respectively, based on the first band input and at the least one further band input to provide a first band output and a second band output, respectively. The predistortion actuator drives an output port configured to be coupled to an amplifier. The system further has a processor coupled to an evaluation input, which is couplable to an output of the amplifier. A coefficient calculation block is coupled to a processor output, the first band input, and the at least one further band input. The coefficient calculation block calculates first and the further adjustable distortion coefficients based on the first band input, the at least one further band input and the processor output.

System and method for multi-band predistortion

A predistortion actuator is provided. The predistortion actuator includes a plurality of branches, each of which implements a basis function that acts on a digital input signal. For at least one of the branches, the respective basis function is a sectioned basis function, where each section of the sectioned basis function corresponds to a respective section of a range of at least one input signal characteristic associated with the digital input signal, such as a value range of a magnitude, a temporal characteristic, or a hybrid of the two. A power amplifier system including the predistortion actuator is also provided. Utilizing sectioned basis functions can potentially reduce the hardware resources necessary to realize the predistortion actuator relative to conventional global basis functions. In addition, signal conditioning during coefficient training can potentially be used to reduce the dynamic range of coefficients associated with each sectioned basis function.

Predistortion with sectioned basis functions

The present invention provides a technique for reducing power levels associated with two or more input signals using peak reduction distortion that is derived from a combined signal, which represents a combination of the input signals.

Reducing power levels associated with two or more signals using peak reduction distortion that is derived from a combined signal

Cordic based complex tuner with exact frequency resolution

The present invention provides a technique for reducing the peak power of a combined signal that has a first signal of a first modulation type and a second signal of a second modulation type. Based on the combined signal, peak reduction distortion is determined. The peak reduction distortion is configured such that, if applied to the entirety of the combined signal, excessive peaks throughout the combined signal would be reduced. However, instead of applying the entirety of the peak reduction distortion, a selected portion of the peak reduction distortion is applied to a corresponding portion of the combined signal to reduce the peak power of the combined signal.

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Carp, Canada

Arthur Thomas Gerald Fuller