Abstract: A technique for generating a bit log-likelihood ratio (LLR) in a communication system includes generating a demodulated signal based on a received symbol and a reference symbol. An input for a bit LLR generator is generated based on the demodulated signal and a normalization value that is based on the received symbol or the reference symbol. A bit LLR is generated for the received symbol, using the bit LLR generator, based on the input.

Abstract: Methods and systems are disclosed for frequency-domain frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency domain components associated with subcarriers within the multi-carrier communication signals. A sliding-window correlation (e.g., two-dimensional sliding window) is applied to the received symbols represented in the frequency domain to detect frame boundaries for multi-carrier signals. The sliding-window frame synchronization can be applied by itself or can be applied in combination with one or more additional frame synchronization stages. The disclosed embodiments are particularly useful for frame synchronization of multi-carrier signals in PLC (power line communication) systems.

Abstract: Methods and systems are disclosed for frequency-domain amplitude normalization for symbol correlation in multi-carrier communication systems. Digital samples associated with input signals received from a communication medium are processed using a Fast Fourier Transform (FFT) to generate complex frequency components. Each complex frequency component is normalized with respect to its amplitude, and the frequency-domain, amplitude-normalized frequency components are multiplied with frequency components for reference symbol(s) to generate frequency-domain correlation values. These frequency-domain correlation values are analyzed to determine if a correlation exists between the amplitude-normalized frequency components and the predetermined reference frequency components. A correlation detection output is then generated that indicates whether or not a symbol synchronization was achieved.

Abstract: A transmitter and method for processing a digitally modulated communication signal, which may reduce peak-to-average-power-ratio (PAPR) while maintaining acceptable error rates is disclosed. After subcarrier mapping, a first digital representation of the signal is upsampled into a second digital representation, which is transformed into a first time domain representation. Samples whose magnitudes exceed a magnitude limit are limited to that limit to produce a second time domain representation. The second time domain representation is transformed to a third frequency domain representation, which is downsampled into a fourth frequency domain representation. In addition to the in-band subcarriers, some out-of-band subcarriers adjacent to the frequency band are preserved while the remaining out-of-band subcarriers are eliminated to produce a fifth frequency domain representation.

Abstract: A technique for generating a bit log-likelihood ratio (LLR) in a communication system includes generating a demodulated signal based on a received symbol and a reference symbol. An input for a bit LLR generator is generated based on the demodulated signal and a normalization value that is based on the received symbol or the reference symbol. A bit LLR is generated for the received symbol, using the bit LLR generator, based on the input.

Abstract: A technique for detecting symbols includes performing an over-sized discrete Fourier transform (DFT) operation on a received signal that includes at least two repeated symbols. A sum of signal characteristics for subcarriers of one or more possible symbols are determined based on the DFT operation. A sum of signal characteristics for non-subcarriers of the one or more possible symbols is determined based on the DFT operation. Finally, a determination is made as to whether one or more of the one or more possible symbols is detected based on the sum of signal characteristics for the subcarriers and sum of signal characteristics for the non-subcarriers.

Abstract: Methods and systems are disclosed for frequency-domain symbol and frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency components associated with subcarriers within the multi-carrier communication signals. Symbol synchronization is performed in the frequency domain by performing correlation(s) between frequency components of the received signal and frequency-domain synchronization symbol(s). After symbol synchronization, frame synchronization correlation is also performed in the frequency domain between frequency components of the received signal and frequency-domain synchronization symbol(s). The disclosed embodiments are particularly useful for symbol and frame synchronization in multi-carrier received signals for power line communication (PLC) systems and/or other harsh noisy communication environments.

Abstract: Methods and systems are disclosed for frequency-domain amplitude normalization for symbol correlation in multi-carrier communication systems. Digital samples associated with input signals received from a communication medium are processed using a Fast Fourier Transform (FFT) to generate complex frequency components. Each complex frequency component is normalized with respect to its amplitude, and the frequency-domain, amplitude-normalized frequency components are multiplied with frequency components for reference symbol(s) to generate frequency-domain correlation values. These frequency-domain correlation values are analyzed to determine if a correlation exists between the amplitude-normalized frequency components and the predetermined reference frequency components. A correlation detection output is then generated that indicates whether or not a symbol synchronization was achieved.

Abstract: Methods and systems are disclosed for frequency-domain carrier blanking in multi-carrier communication systems. When excessive energy is detected in one or more subcarriers within a received symbol for multi-carrier communications, those subcarriers are blanked for subsequent demodulation in order to avoid corruption of the demodulated data. A conversion from time-domain digital samples to frequency-domain values using an FFT (Fast Fourier Transform) and a threshold detector are utilized to detect corrupted subcarriers. Further, this frequency-domain carrier blanking can be implemented dynamically on a symbol-by-symbol basis to further improve demodulation performance by reducing decoding errors. The disclosed embodiments are particularly useful for improving demodulation performance in power line communication (PLC) systems.

Abstract: Methods and systems are disclosed for frequency-domain frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency domain components associated with subcarriers within the multi-carrier communication signals. A sliding-window correlation (e.g., two-dimensional sliding window) is applied to the received symbols represented in the frequency domain to detect frame boundaries for multi-carrier signals. The sliding-window frame synchronization can be applied by itself or can be applied in combination with one or more additional frame synchronization stages. The disclosed embodiments are particularly useful for frame synchronization of multi-carrier signals in PLC (power line communication) systems.

Abstract: A method for processing a plurality of symbol streams is provided. The method includes receiving a first symbol stream, wherein the first symbol stream has a corresponding first number of retransmissions. The method further includes receiving a second symbol stream, wherein the second symbol stream has a corresponding second number of retransmissions. The method further includes selecting the first symbol stream for decoding, if the first number of retransmissions is greater than the second number of retransmissions.

Abstract: The invention is a process to encourage and simplify preventive medical practices. The process includes selecting known effective in-home medical test kits from laboratories and making these kits available to users for order through a website. The fulfillment of the orders from the labs as well as the collection of the results is coordinated. The results are consolidated with appropriate analysis into a report which is made available to the user through the website on a restricted basis, such as password control. The process may optionally include a health risk assessment questionnaire which guides the user in test kit selection. The process can be initiated by an employer in the form of an invitation to an employee to participate, and the website can be customized and co-branded with the employer.

Abstract: The present invention provides a method, system and computer program product for extracting data-points from a data file. A data-point is extracted in a data-base by pointing at a portion of computer recognizable text in the data file by a pointing device. The data-point associated with the pointed portion of the computer recognizable text is thereby selected and stored in the database.

Abstract: A method for processing a plurality of symbol streams is provided. The method includes receiving a first symbol stream, wherein the first symbol stream has a corresponding first number of retransmissions. The method further includes receiving a second symbol stream, wherein the second symbol stream has a corresponding second number of retransmissions. The method further includes selecting the first symbol stream for decoding, if the first number of retransmissions is greater than the second number of retransmissions.