| Patent application number | Description | Published |
|---|
| 20080267268 | Method of Converting a Digital Bb (Baseband) Signal Into an Analog (Intermediate-Frequency) Signal - The invention relates to a method of converting a digital BB (baseband) signal into an analog IF (intermediate-frequency) signal, wherein the digital BB processor signal is oversampled K times by means of a BB/IF converter, and each i | 10-30-2008 |
| 20080310532 | Method for Signal Reception - In an OFDM mobile communications system, an algorithm for forming a preliminary estimate of the channel on pilot subcarriers is carried out. Based on this preliminary estimate, a channel property is estimated. This channel property is then used to decide whether to enter a mobile receiver mode or a stationary receiver mode. For example, in the mobile mode channel estimation is performed using only pilot symbols from the current symbol period, while in the static mode channel estimation is performed using pilot symbols from the current symbol period and pilot symbols from other symbol periods. | 12-18-2008 |
| 20090177726 | METHOD FOR PROCESSING A DIGITAL INPUT SIGNAL IN A DIGITAL DOMAIN AND DIGITAL FILTER CIRCUIT FOR PROCESSING A DIGITAL INPUT SIGNAL - The invention relates to a method for processing a digital input signal (x(i)) in a digital domain, comprising: -sampling a wideband of input frequencies of said digital input signal (x(i)) with a sampling frequency (fs), which decimates with a decimation factor (D), -linear shaping said sampled input frequencies with a configurable delay, -producing an output signal (y(i)) containing said linear shaped input frequencies, wherein the output signal (y(i)) has the same sampling frequency (fs) as said input signal (x(i)). | 07-09-2009 |
| 20090232257 | METHOD AND SYSTEM FOR IMPACT MITIGATION OF SUDDEN CARRIER FREQUENCY SHIFTS IN OFDM RECEIVERS - This disclosure relates to a method and system for impact mitigation of sudden carrier frequency shifts in OFDM receivers that transforming a received complex digital baseband signal and decoding data from the transformed signal. | 09-17-2009 |
| 20090270053 | CALIBRATING AMPLITUDE AND PHASE IMBALANCE AND DC OFFSET OF AN ANALOG I/Q MODULATOR IN A HIGH-FREQUENCY TRANSMITTER - The object of the invention, which relates to a method and an arrangement for calibrating an analog I/Q modulator in a high-frequency transmitter, is to provide a method and an associated circuit arrangement by means of which a calibration of the I/Q modulator is carried out without a balancing operation and thus the complexity is minimized. According to the invention, this object is achieved, in terms of the method, in that transmission signals are produced by the I/Q modulator in three method steps in accordance with the method and said transmission signals are in each case evaluated and the results of the evaluations are stored, in that, in a fourth method step, improved compensation coefficients are calculated on the basis of the results of the previous evaluations, which improved compensation coefficients can be used for a subsequent run-through of the method, and in that the run-throughs of the method are repeated until the error of the amplitude and/or phase response of the I/Q modulator lies below a defined threshold value or a defined number of run-throughs of the method is reached. | 10-29-2009 |
| 20100290569 | POST DFT/FFT TIME TRACKING ALGORITHM FOR OFDM RECEIVERS - A method for time synchronization tracking in an orthogonal frequency division multiplexing (OFDM) receiver is described, the method comprising the steps: obtaining a DFT output vector; determining a sample timing offset indication using reference symbols that are extracted from the DFT output vector; and adapting the OFDM symbol timing using said determined indication. In order to provide an improved post-DFT algorithm for estimating a time tracking error in OFDM receivers such as to allow an effective time tracking even in single frequency networks, and more particular to devise a time tracking algorithm for OFDM receivers that supports longer channel impulse responses without causing inter-symbol interference, said determining step comprises the steps of: (a) estimating ( | 11-18-2010 |
| 20100296568 | METHOD AND APPARATUS TO CANCEL ADDITIVE SINUSOIDAL DISTURBANCES IN OFDM RECEIVERS - Orthogonal frequency division multiplexing (OFDM) has become a popular transmission method for high speed wireless radio transmission, due to its potential for low complexity of transmitters and receivers. A method and apparatus are contemplated for cancelling additive sinusoidal disturbances of a known frequency in OFDM receivers which arise e.g. from clock signals that are present for frequency reference, mixer control, and A/D converter control, as well as harmonics and mixing products of those periodic signals, coupling into some point in the receiver chain and appearing as rotating complex exponentials superimposed to complex baseband receive signals. According to the inventive method and apparatus an estimation of an amplitude and phase of a disturbing superimposed tone with a known frequency is obtained and the amplitude and phase estimation is used to cancel the spurious tone preventing a degradation of receiver sensitivity while achieving low implementation complexity. | 11-25-2010 |
| 20110058618 | METHOD AND APPARATUS FOR INTERFERENCE MITIGATIONI IN A BASEBAND OFDM RECEIVER - A method of compensating interference of received symbols in a MIMO OFDM receiver employs MMSE equalization and LLR scaling, and a MIMO OFDM receiver includes a linear MMSE equalizer. The method provides a low-complexity, numerically robust method for compensating interference of received symbols and provides a low-cost, robust digital baseband receiver for MIMO-OFDM, achieved by merging linear MMSE equalization and scaling of the corresponding equalized symbols into a single algorithm that, for the 2×M MIMO case, completely avoids computationally extensive matrix inversion and allows for significant simplification of symbol detection as compared to separate equalization and scaling. | 03-10-2011 |
