Patent application number | Description | Published |
20080273497 | Handover for DVB-H - A method of wireless handover in a broadcast network (FIGS. | 11-06-2008 |
20100246714 | METHOD AND SYSTEM FOR CREST FACTOR REDUCTION - An apparatus and system are provided for crest factor reduction (CFR). Preferably, a peak from the wideband signal is detected. A gain from the magnitude of the peak and a threshold can then be calculated. Based on this information, each carrier's contribution to the peak can be approximated, and a cancellation pulse coefficient for each carrier from its contribution to the peak can be calculated. A base cancellation pulse can be calculated from the cancellation pulse coefficients for each carrier, and a cancellation pulse can be calculated from the base cancellation pulse and the gain, which can then be applied to the wideband signal. | 09-30-2010 |
20110080216 | Systems and Methods of Power Amplifier Digital Pre-Distortion - Systems and methods for power amplifier pre-distortion are provided. The systems and methods of power amplifier digital pre-distortion disclosed herein may include a generic pre-distorter architecture which can implement a variety of Volterra cross terms involving single dimension convolutions (first order dynamics). For hardware implementations, this generic pre-distorter is further fine-tuned to provide a choice between different sets of cross terms that can be selected for a given PA for optimal performance. The novel pre-distorter architecture provides flexibility to trade off memory depth for additional Volterra terms and vice versa. A further novelty is the ability to trade off both memory depth and cross terms for a higher sample rate operation, which may enable higher order non-linear pre-distortion, or support for higher signal bandwidths. A poly-phase non-linear filtering mode allows for this flexibility. | 04-07-2011 |
20110090107 | TIME-INTERLEAVED-DUAL CHANNEL ADC WITH MISMATCH COMPENSATION - Previously, when designing receivers for radio frequency (RF) or wireless communications, designers chose between time-interleaved (TI) analog-to-digital converters (ADCs) for intermediate frequency architectures and dual channel ADCs for direct conversion architectures. Here, similarities between TI ADCs and dual channel ADC were recognized, and an ADC that has the capability of operating as a TI ADCs and dual channel ADC is provided. This allows designer to have greatly increased flexibility during the design process which can greatly reduce design costs, while also allowing the manufacturer of the ADC to realize a reduction in its operating costs. | 04-21-2011 |
20110158297 | JOINT TRANSMIT AND RECEIVE I/Q IMBALANCE COMPENSATION - Conventional transceivers do provide some compensation for in-phase/quadrature (I/Q) imbalance. However, these techniques do not separately compensate for I/Q imbalance for the transmitter and receiver sides of the transceiver. Here, a transceiver is provided that allows for compensation of I/Q imbalance in the transmitter and receiver irrespective of the other to allow for a more accurate transceiver. | 06-30-2011 |
20120069931 | MULTI-BAND POWER AMPLIFIER DIGITAL PREDISTORTION SYSTEM AND METHOD - Traditionally, for multi-band communication systems, independent signal chains for each of the different bands are employed. By using such an architecture, there are a large number of components, and there is substantial power consumption. Here, transmit processor is provided that enables transmission across multiple bands using few components (namely, fewer signal chains), while also provided for digital predistortion. | 03-22-2012 |
20120134399 | Systems and Methods of Improved Power Amplifier Efficiency Through Adjustments in Crest Factor Reduction - Crest factor reduction algorithms described herein may be used to improve power amplifier efficiency during low signal power conditions compared to traditional static threshold techniques. Techniques described herein insure that the signal power level at the output of the crest fact reduction block is held constant relative to the input power level under all signal power level conditions. Two different solutions may be implemented together or separately to achieve the desired conditions. The first technique provides constant ratio between input power and output power. Constant ratio of peak and average output levels keeps the amount of crest factor reduction applied to the signal constant, irrespective of the signal power level. A second technique is to hold signal power level constant in respect to the amount of crest factor reduction applied. | 05-31-2012 |
20120250790 | FREQUENCY SELECTIVE IQ CORRECTION - In conventional radio frequency (RF) systems, transmitters will usually convert baseband signals to RF so as to be transmitted. As part of the conversion process, the transmitters will perform digital preditortion (DPD), which uses feedback from a power amplifier. However, there are usually mismatches between the in-phase (I) and quadrature (Q) paths within with feedback loop. Traditional IQ correction filters were ineffective at providing adequate compensation for these mismatches, but here a filter is provided that provides adequate out-of-band compensation by use of frequency selectivity. | 10-04-2012 |
20130083834 | Power-Indexed Look-Up Table Design of Digital Pre-Distortion for Power Amplifiers with Dynamic Nonlinearities - This invention is a method of power amplifier digital pre-distortion which measures a current power level of the power amplifier, stores in a look up table entries consisting of a power level and a corresponding set of digital pre-distortion coefficients, selects a set of digital pre-distortion coefficients corresponding to the measured power level. If the measured current power level is near a power level index, the digital pre-distortion coefficients correspond to the power level index. If the measured current power level is greater than the maximum power level entry, the digital pre-distortion coefficients is of the maximum power level entry. If the measured current power level is less than the minimum power level entry, the digital pre-distortion is of the minimum power level entry. If the measured current power level is not near a power level index, the digital pre-distortion coefficients are an interpolation. | 04-04-2013 |
20140140452 | CREST FACTOR REDUCTION FOR SIGNALS WITH DYNAMIC POWER AND FREQUENCY DISTRIBUTION - A method to form a CFR cancellation filter for signals with dynamic power and frequency distribution by estimating the filter at the rate required by the input signal's dynamics. For mixed mode systems (for example CDMA and LTE) the CFR is computed for each stream, and combined to form the final filter. | 05-22-2014 |
20140169496 | Crest Factor Reduction for Multi-Band System - Systems and methods for crest factor reduction (CFR) are described. A multi-band CFR architecture achieves significant hardware savings without sacrificing CFR performance by applying peak cancellation to each band individually. However, peak detection is calculated based on a combined input signal. | 06-19-2014 |
20140294120 | DUAL LOOP DIGITAL PREDISTORTION FOR POWER AMPLIFIERS - A method of predistorting an input signal ( | 10-02-2014 |
20150030099 | CIRCUITS AND METHODS FOR REDUCING THE AMPLITUDE OF COMPLEX SIGNALS - For crest factor reduction in a first signal having first and second components, the first component is delayed. A second signal is generated in response to detecting that a peak in the first component exceeds a predetermined threshold. Amplitude of the peak in the first component is reduced in response to detecting that the peak in the first component exceeds the predetermined threshold. Reducing amplitude of the peak in the first component includes adding the second signal to the delayed first component. | 01-29-2015 |
20150085748 | SYSTEM AND METHOD FOR CONTROLLING PEAK TO AVERAGE POWER RATIO - A system and method for reducing peak to average power ratio in a wireless communication system. A wireless communication system includes a radio frequency wireless transmitter that includes signal peak reduction circuitry configured to reduce peak to average power ratio of a signal to be transmitted by reducing amplitude of the signal to be transmitted that is greater than a predetermined amplitude. The signal peak reduction circuitry includes a bit inverter configured to invert a bit of a symbol identified as causing the amplitude of the signal to exceed the predetermined amplitude. The bit inverter is also configured to select the bit to invert such that inversion of the bit reduces the amplitude of the signal, and such that forward error correction in a receiver wirelessly coupled to the transmitter restores the bit to a pre-inversion value. | 03-26-2015 |