Patent application number | Description | Published |
20080211576 | Linearization of RF Power Amplifiers Using an Adaptive Subband Predistorter - Predistorting an input signal prior to amplification in an RF power amplifier ( | 09-04-2008 |
20090245084 | SYSTEM AND METHOD FOR COMMUNICATING DATA USING EFFICIENT FAST FOURIER TRANSFORM (FFT) FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) - A system communicates data and includes a transmitter for transmitting a communications signal that carries communications data. It includes an efficient modulator for approximating the frequencies of sine/cosine basis waveforms using complex exponential functions and adding and subtracting the complex exponential functions to generate an Orthogonal Frequency Division Multiplexed (OFDM) communications signal as a plurality of N data subcarriers that carry communications data as data symbols. A receiver receives the OFDM communications signal and includes a demodulation circuit for demodulating the OFDM communications signal using logical shifts of multiples +/−2 | 10-01-2009 |
20090245397 | SYSTEM AND METHOD FOR COMMUNICATING DATA USING EFFICIENT FAST FOURIER TRANSFORM (FFT) FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) DEMODULATION - A communications device includes a signal input that receives an orthogonal frequency division multiplexed (OFDM) communications signal. A demodulator is connected to the signal input for receiving the OFDM communications signal and demodulating the OFDM communication signal. It includes at least one memory element for storing the at least one sine/cosine basis waveform approximation as complex exponential functions. A logic circuit performs logical shifts in additions and multiples of ±2 | 10-01-2009 |
20090245406 | SYSTEM AND METHOD FOR COMMUNICATING DATA USING EFFICIENT FAST FOURIER TRANSFORM (FFT) FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) MODULATION - A communications device includes at least one memory device for storing complex exponential functions as approximations of sine and cosine basis waveforms. A logic circuit adds and subtracts the complex exponential functions to generate an Orthogonal Frequency Division Multiplexed (OFDM) communications signal as a plurality of N data subcarriers that carry communications data. The logic circuit provides efficient and accurate implementation of the IFFT for use as an OFDM modulator using additions of stored complex exponentials and modulation of the integer-valued QAM data symbols using logic shifts and sign changes (2's complement). | 10-01-2009 |
20090251211 | FEEDFORWARD LINEARIZATION OF RF POWER AMPLIFIERS - RF amplifier system ( | 10-08-2009 |
20100080265 | ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) COMMUNICATIONS DEVICE AND METHOD THAT INCORPORATES LOW PAPR PREAMBLE AND FREQUENCY HOPPING - A communications device includes communication data and a training sequence corresponding to a preamble. A modulation and mapping circuit modulates the communications data and training sequence into a plurality of multiple subcarriers that are orthogonal to each other to form an OFDM communications signal having modulated subcarriers carrying the communications data forming a data payload and modulated subcarriers forming the preamble. A pseudo-random signal generator is operative with the modulation and mapping circuit and generates pseudo-random signals based on an encryption algorithm for frequency hopping each subcarrier at an OFDM symbol rate. The modulation and mapping circuit applies a quadratic modulation to the subcarriers carrying the training sequences to produce a low peak-to-average power ratio (PAPR) preamble with a PAPR value of approximately 2.6 decibels (dB). | 04-01-2010 |
20100080309 | LOW PEAK-TO-AVERAGE POWER RATIO (PAPR) PREAMBLE FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) COMMUNICATIONS - A communications device includes communications data and a training sequence corresponding to a preamble. A modulation and mapping circuit modulates the communications data and training sequence into a plurality of multiple subcarriers that are orthogonal to each other to form an orthogonal frequency division multiplexing (OFDM) communications signal having modulated subcarriers carrying the communications data forming a data payload and modulated subcarriers forming the preamble. The modulation and mapping circuit applies a quadratic modulation to the subcarriers carrying the training sequences to produce a low peak-to-average power (PAPR) preamble of approximately 2.6 decibels (dB) independent of the number of subcarriers. | 04-01-2010 |
20100080310 | ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) COMMUNICATIONS DEVICE AND METHOD THAT INCORPORATES LOW PAPR PREAMBLE AND VARIABLE NUMBER OF OFDM SUBCARRIERS - A communications device includes communications data and a training sequence corresponding to a preamble. A modulation and mapping circuit modulates the communications data and training sequence into a plurality of multiple subcarriers that are orthogonal to each other to form an OFDM communication signal having modulated subcarriers carrying the communications data forming a data payload and modulated subcarriers forming the preamble. A circuit turns OFF and ON selected subcarriers based on an encryption algorithm to increase transmit power and signal-to-noise ratio and reduce the Inter-Carrier Interference (ICI). The modulation and mapping circuit applies a quadratic modulation to the subcarriers carrying the training sequences to produce a low peak-to-average power ratio (PAPR) preamble with a PAPR value of approximately 2.6 decibels (dB). | 04-01-2010 |
20100080311 | ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) COMMUNICATIONS DEVICE AND METHOD THAT INCORPORATES LOW PAPR PREAMBLE AND RECEIVER CHANNEL ESTIMATE CIRCUIT - A communications device includes a demapping and demodulation circuit that demaps and demodulates an OFDM communications signal as modulated subcarriers carrying communications data and modulated subcarriers carrying a training sequence forming a preamble that includes a long sync sequence for channel and frequency offset estimation having a extended guard interval (GI). The OFDM subcarriers carrying the training sequence have a quadratic modulation to produce a low peak-to-average power (PAPR) preamble with PAPR of approximately 2.6 decibels (dB). A channel estimate circuit is positioned to receive signals after processing within a FFT circuit and subcarrier demapper circuit and estimates the channel characteristics of the communications channel based on splitting the extended guard interval from the long sync sequence and processing into values that represent the low PAPR preamble as plus or minus one (±1) values in a real or imaginary component as adds and subtracts. | 04-01-2010 |
20100080312 | ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) COMMUNICATIONS DEVICE AND METHOD THAT INCORPORATES LOW PAPR PREAMBLE WITH CIRCUIT FOR MEASURING FREQUENCY RESPONSE OF THE COMMUNICATIONS CHANNEL - A communications device includes a demapping and demodulation circuit and processes an OFDM communications signal that includes modulated subcarriers carrying communications data forming a data payload and modulated subcarriers carrying a training sequence forming a preamble. Those OFDM subcarriers carrying the training sequence have a sample for each subcarrier at a frequency bin using evenly spaced, equal amplitude subcarriers that have a set phase of each sinusoid to a specific angle with quadratic phase to form a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB). A channel estimate circuit is operative for measuring fluctuations within a flat-top spectrum of the received OFDM communications signal corresponding to the preamble to reflect the frequency response of the communications channel. | 04-01-2010 |
20110129023 | WIRELESS RANGING SYSTEM AND RELATED METHODS - A wireless ranging system for determining a range of a remote wireless device may include a wireless transmitter and a wireless receiver. The wireless ranging system may also include a ranging controller to cooperate with the wireless transmitter and receiver to generate a multi-carrier base waveform, transmit a sounder waveform to the remote wireless device including concatenated copies of the multi-carrier base waveform, and receive a return waveform from the remote wireless device in response to the sounder waveform. The ranging controller may also generate time domain samples from the return waveform, convert the time domain samples into frequency domain data, and process the frequency domain data to determine the range of the remote wireless device. | 06-02-2011 |