Patent application number | Description | Published |
20080219338 | QUADRATURE MODULATION ROTATING TRAINING SEQUENCE - A system and method are provided for transmitting a rotating training sequence. A rotating training signal is generated in quadrature modulation transmitter. The rotating training signal includes training information sent via an in-phase (I) modulation path, as well as training information sent via a quadrature (Q) modulation path. The rotating training signal may be generated by initially sending training information via the I modulation path, and subsequently sending training information via the Q modulation path. The training information sent via the I modulation path may include a first symbol having a reference phase (e.g., 0 degrees or 180 degrees). Then, the training information sent via the Q modulation path would include a second symbol having a phase that is ±90 from the reference phase. | 09-11-2008 |
20080219339 | CHANNEL ESTIMATION USING FREQUENCY SMOOTHING - A system and method are provided for supplying a frequency-smoothed communications training signal. The method generates a frequency-smoothed unbiased training signal in a quadrature modulation transmitter. The frequency-smoothed unbiased training signal includes a plurality of pilot signal products, where each pilot signal product includes complex plane information represented by a reference frequency subcarrier, multiplying complex plane information represented by mirror frequency subcarrier. The sum of the plurality of pilot signal products is equal to zero. The method supplies the frequency-smoothed unbiased training signal so that it may be transmitted within a single symbol period. System and methods are also provided for using a frequency-smoothed training signal in the calculation of a receiver channel estimate. | 09-11-2008 |
20080219379 | QUADRATURE IMBALANCE MITIGATION USING UNBIASED TRAINING SEQUENCES - A system and method are provided for transmitting an unbiased communications training sequence. The method generates an unbiased training sequence in a quadrature modulation transmitter. The unbiased training sequence represents a uniform accumulated power evenly distributed in the complex plane. As a result, training information in the time domain is sent via an in-phase (I) modulation path having an accumulated power. Training information in the time domain is sent via a quadrature (Q) modulation path having an accumulated power equal to the I modulation path power. Also provided are system and method for calculating an unbiased channel estimate from a received unbiased training sequence. | 09-11-2008 |
20080219386 | QUADRATURE IMBALANCE ESTIMATION USING UNBIASED TRAINING SEQUENCES - A system and method are provided for removing quadrature imbalance errors in received data. The method accepts an unbiased training sequence in a quadrature demodulation receiver. An unbiased training sequence has a uniform accumulated power evenly distributed in a complex plane, and includes predetermined reference signals (p) at frequency +f and predetermined mirror signals (p | 09-11-2008 |
20080225982 | METHOD AND APPARATUS FOR CODING A COMMUNICATION SIGNAL - An apparatus for coding a communication signal is provided. The apparatus includes an encoder configured to encode the communication signal, to increase the length of the communication signal, and a repetition coder configured to repetitively code part of the encoded communication signal, to utilize at least some of the increased length of the communication signal. The apparatus further includes an interleaver configured to interleave the repetitively coded communication signal. A method is also provided for coding a communication signal. | 09-18-2008 |
20090004984 | ENHANCED FREQUENCY DOMAIN SPREADING - A system and method are provided for using frequency domain spreading to generate real signals in the time domain. The method supplies a first complex frequency domain symbol (α) and a second complex frequency domain symbol (α | 01-01-2009 |
20090161804 | Receiver window shaping in OFDM to mitigate narrowband interference - A receiver window for symbol extraction is provided. A symbol is spread across a plurality of sub-carriers of a frequency band for transmission. If the frequency band is affected by narrowband interference, the receiver window concentrates the narrowband interference energy to minimize its effect on distant sub-carriers within the frequency band. The receiver window is shaped for extracting the symbol from the frequency band, wherein the receiver window has a starting point before the start of the symbol. The receiver window overlaps a previous receiver window for the previous adjacent symbol on the same frequency band. The receiver window is shaped by overlapping and adding a channel impulse response segment from a zero-padded portion of the symbol to the beginning of the symbol and overlapping and adding a second portion from the previous zero-padded symbol (from the same frequency band) to the end of the symbol. | 06-25-2009 |
20120039421 | QUADRATURE IMBALANCE ESTIMATION USING UNBIASED TRAINING SEQUENCES - A system and method are provided for removing quadrature imbalance errors in received data. The method accepts an unbiased training sequence in a quadrature demodulation receiver. An unbiased training sequence has a uniform accumulated power evenly distributed in a complex plane, and includes predetermined reference signals (p) at frequency +f and predetermined mirror signals (p | 02-16-2012 |