Patent application number | Description | Published |
20110255638 | CHANNEL ESTIMATION FOR EQUALIZER USING SERIAL LOCALIZATION WITH INDECISION - In a receiver with a multi-stage equalizer, such as an SLI equalizer, cumulative symbol estimates generated in one or more early stages of the equalizer are used as effective pilot symbols to improve channel estimation for later stages. | 10-20-2011 |
20110268232 | INTER-CARRIER BANDWIDTH CONTROL FOR MITIGATING IQ IMBALANCE - Digital IQ imbalance estimation and compensation is facilitated by shaping the frequency response of receiver branches. In particular, in a multi-carrier receiver, the frequency response of signal processing elements in at least one receiver branch is set to not fully attenuate received signals in a frequency band of interest. The frequency band of interest is greater than the carrier bandwidth of the received signal processed by that receiver branch. In some embodiments, the received signal is not attenuated, and adjacent interfering signals are partially attenuated. This allows information regarding the interfering signals to appear in an IQ imbalance-induced, inter-carrier image of the signals in anther receiver branch, facilitating digital estimation and compensation of IQ imbalance. | 11-03-2011 |
20110310932 | SYSTEM AND METHOD OF SINGLE-CARRIER LAYER SHIFTING FOR MULTIPLE-STREAM TRANSMISSION FACILITATING SIC IMPLEMENTATION - A system, method and node of single-carrier layer shifting for multiple-stream transmission in a network. Per-symbol layer shifting for multiple-stream transmission is implemented using DFTS-OFDM as an access technique. Code word-to-layer mapping is fixed within a DFTS-OFDM symbol and only shifted across consecutive DFTS-OFDM symbols. The method begins by receiving a multiple-stream transmission by a mapping module for transmission. The transmission includes a plurality of subframes and information carrying symbols transmitted on a plurality of layers. A per-symbol layer shifting scheme is then implemented on the transmission where layer shifting is conducted upon each symbol. | 12-22-2011 |
20120033683 | Method and Receiver For Jointly Decoding Received Communication Signals Using Maximum Likelihood Detection - The present invention relates to a method in a receiver for decoding at least two received communication signals, wherein the communication signals are modulated, pre-coded by a discrete Fourier transform and transmitted by means of single-carrier frequency division multiple access scheme (SC-FDMA). The method comprises the steps of: performing an antenna combining and equalization on a signal observed at the receiver; performing inverse discrete Fourier transform on a model of the observed signal; whitening a time domain model of the observed signal; and jointly detecting the received at least two communication signals by performing soft value calculations based on maximum likelihood detection of a whitened time domain model using a whitened time domain channel estimate. | 02-09-2012 |
20120120997 | METHODS AND SYSTEMS FOR PRECODER SELECTION ASSISTED BY DEMODULATION REFERENCE SIGNALS (DM-RS) - Systems and methods according to these exemplary embodiments provide for using demodulation reference signals (DM-RSs) to obtain channel state information (CSI) for precoder selection. A method includes: receiving a DM-RS in at least one subframe, determining the CSI from the DM-RS; and using the CSI to perform at least one function. | 05-17-2012 |
20120170629 | Controllable Frequency Offset for Inphase and Quadrature (IQ) Imbalance Estimation - Embodiments of user equipment and methods for determining IQ imbalance parameters are described. In some embodiments, a method for determining in-phase (I) and Quadrature (Q) imbalance (IQ imbalance) parameters based on a known signal in a dual-carrier receiver using at least one controllable frequency offset includes receiving a known signal modulated onto a first radio frequency (RF) carrier frequency and a second RF carrier frequency different than the first RF carrier frequency; downconverting the known signal to a baseband signal for the first and second carriers by conversion from the respective RF carrier frequencies to an intermediate frequency (IF) using a common RF local oscillator (LO) and by further conversion from IF to baseband using carrier specific IF LOs, wherein as a controllable frequency offset is used as a part of the conversion from at least one of RF to IF and IF to baseband through the LOs; removing any controllable frequency offset from the baseband signal for the first and second carriers to produce representations of the received signals of the first and second carriers; and deriving IQ imbalance parameters for each representation of the received signals of the first and second carriers using a least square estimate. | 07-05-2012 |
20120177147 | METHODS OF RECEIVING MULTIPLE CARRIERS USING DIFFERENT RF MIXER FREQUENCIES AND RELATED COMMUNICATIONS DEVICES AND RECEIVERS - Methods may be provided to simultaneously receive first and second RF (radio frequency) carriers over respective first and second RF carrier frequencies. More particularly, the first and second RF carriers may be provided at an RF mixer stage. During a first time period, the first and second RF carriers may be down converted through the RF mixer stage using a first RF mixer frequency to generate first downconverted signals, and the first downconverted signals may be processed to provide first and second DC carriers corresponding to the first and second RF earners. During a second time period, the first and second RF carriers may be downconverted through the RF mixer stage using a second RF mixer frequency to generate second downconverted signals with the first and second RF mixer frequencies being different, and the second downconverted signals may be processed to provide the first and second DC carriers corresponding to the first and second RF carriers. Related devices are also discussed. | 07-12-2012 |
20120230372 | DIGITAL IQ IMBALANCE COMPENSATION FOR DUAL-CARRIER DOUBLE CONVERSION RECEIVER - Digital IQ imbalance compensation is utilized for a dual-carrier double conversion receiver. First, the effect of IQ imbalance on OFDM-based digital baseband is analyzed, showing that, in the presence of IQ imbalance, the baseband signal of each carrier is obtained from its own branch as well as the other branch. Second, IQ imbalance parameters of interest are estimated using pilot signals and compensated using only digital baseband processing. | 09-13-2012 |
20130028309 | TRANSMISSION MODE ADAPTATION IN A WIRELESS NETWORK - Conventional mode adaptation does not account for the gain imbalance between channels for measurement and for data reception. Therefore, the precoder, which is selected based on the measurement channel, may not be the optimal precoder for the data reception channel. By maintaining relative SINR ordering between transmission modes, a receiver may select the transmission mode for a transmitter that maximizes the actual throughput even in the presence of inter-antenna gain increase or decrease. | 01-31-2013 |
20130343492 | Controllable Frequency Offset for Inphase and Quadrature (IQ) Imbalance Estimation - Embodiments of user equipment and methods for determining IQ imbalance parameters are described. In some embodiments, a method for determining in-phase (I) and Quadrature (Q) imbalance (IQ imbalance) parameters based on a known signal in a dual-carrier receiver using at least one controllable frequency offset includes receiving a known signal modulated onto a first radio frequency (RF) carrier frequency and a second RF carrier frequency different than the first RF carrier frequency. The known signal is downconverted to a baseband signal for the carriers by conversion from the respective RF carrier frequencies to an intermediate frequency (IF) using a common RF local oscillator (LO) and by further conversion from IF to baseband using carrier specific IF LOs, where a controllable frequency offset is used. Any controllable frequency offset is removed from the baseband signal for the first and second carriers to produce representations of the received signals. | 12-26-2013 |
20140219376 | METHODS AND SYSTEMS FOR PRECODER SELECTION ASSISTED BY DEMODULATION REFERENCE SIGNALS (DM-RS) - Systems and methods according to these exemplary embodiments provide for using demodulation reference signals (DM-RSs) to obtain channel state information (CSI) for precoder selection. A method includes: receiving a DM-RS in at least one subframe, determining the CSI from the DM-RS; and using the CSI to perform at least one function. | 08-07-2014 |
20140348272 | CONTROLLABLE FREQUENCY OFFSET FOR INPHASE AND QUADRATURE (IQ) IMBALANCE ESTIMATION - Embodiments of user equipment and methods for determining IQ imbalance parameters are described. In some embodiments, a method for determining in-phase (I) and Quadrature (Q) imbalance (IQ imbalance) parameters based on a known signal in a dual-carrier receiver using at least one controllable frequency offset includes receiving a known signal modulated onto a first radio frequency (RF) carrier frequency and a second RF carrier frequency different than the first RF carrier frequency. The known signal is downconverted to a baseband signal for the carriers by conversion from the respective RF carrier frequencies to an intermediate frequency (IF) using a common RF local oscillator (LO) and by further conversion from IF to baseband using carrier specific IF LOs, where a controllable frequency offset is used. Any controllable frequency offset is removed from the baseband signal for the first and second carriers to produce representations of the received signals. | 11-27-2014 |