Abstract: A system according to one embodiment includes an automatic gain control circuit configured to provide an amplifier gain value; a temperature sensing circuit configured to provide a temperature; an antenna switching circuit configured to decouple an antenna from the receiver during a noise figure calibration interval; a signal power measurement circuit configured to measure input power to the receiver; a noise figure estimation circuit configured to estimate a receiver noise figure during the noise figure calibration interval based on an initial receiver noise variance, the temperature and the amplifier gain value, wherein the initial receiver noise variance is estimated based on the measured input power during the noise figure calibration interval; and a noise variance tracking circuit configured to calculate updated estimates of the receiver noise variance, wherein the updated estimates are based on updates of the measured temperature and updates of the measured amplifier gain.

Abstract: A method for determining an optimal pulse repetition period (PRP) in a system including a wireless transmission device operating in a static physical transmission environment includes providing a first and second injection-locked transmission system (ILT system). The method further includes implementing an algorithm in a microprocessor within the first ILT system. The algorithm includes synchronizing a receiver clock in the second ILT system with the clock of the first ILT system; setting the PRP equal to an impulse duration, the PRP being very short; increasing the PRP until a bit error rate (BER) at the PRP is less than the bit error rate limit; and based on the determining that the BER is less than the bit error rate limit, setting the PRP as the optimal PRP.

Abstract: A system according to one embodiment includes an automatic gain control circuit configured to provide an amplifier gain value; a temperature sensing circuit configured to provide a temperature; an antenna switching circuit configured to decouple an antenna from the receiver during a noise figure calibration interval; a signal power measurement circuit configured to measure input power to the receiver; a noise figure estimation circuit configured to estimate a receiver noise figure during the noise figure calibration interval based on an receiver noise variance, the temperature and the amplifier gain value, wherein the initial receiver noise variance is estimated based on the measured input power during e noise figure calibration interval; and a noise variance tracking circuit configured to calculate updated estimates of the receiver noise variance, wherein the updated estimates are based on updates of the measured temperature and updates of the measured amplifier gain.

Abstract: Information to be transmitted may be compressed using range coding for adaptive arithmetic coding with a virtual sliding window. Cost and complexity of coding may be reduced in some cases.

Abstract: Methods and systems to modulate and demodulate first and second path bits within sequences of pulses, where each pulse represents first and second path bits and is position-modulated and phase-modulated based on binary values of the corresponding bits, with no more than 1 phase change per N pulses. Position-modulation may be based on first-path bits. Phase-modulation may be based on second-path bits. A modulator first path has an input data rate Q times that of a second path. The first may include an N-bit encoder. The second path may include a Q-bit encoder and an N-bit repetition encoder. A demodulator includes a first path to determine first path bit values based on pulse coordinates integrated over N frames, and a second path to determine second path bit values based on further integration over Q frames.

Abstract: Frequency domain based methods and systems to perform adaptive multi-mode pre-decoding linear equalization, adaptive channel estimation, turbo equalization, turbo equalization iteration control, and noise variance estimation. An adaptive linear pre-decoder equalizer may include a multi-mode equalizer, which may include a blind equalizer to determine initial equalization coefficients and a decision-directed equalizer to refine the initial equalization coefficients. Turbo equalization may include a dynamic iteration termination criterion and/or a fixed termination criterion. Turbo equalization may be based in part on an adaptive estimated noise variance. Methods and systems disclosed herein may be implemented with respect to single-carrier signals such as digital video broadcast signals.

Abstract: A mobile communication device to equalize a Doppler shifted received signal according to one embodiment is configured to: extract one or more pilot signals from a segment of the received signal; perform Minimum Mean Square Error (MMSE) filtering on the extracted pilot signals, wherein the filter provides estimated pilot signal impulse responses; estimate the amplitudes of one or more path components of the estimated pilot signal impulse responses; estimate the phases of one or more path components of the estimated pilot signal impulse responses; and combine the estimated amplitudes and the estimated phases of the path components of the pilot signal impulse responses, wherein the combination provides an estimated channel impulse response.

Abstract: An artifact in a discrete cosine transform based decoder output may be detected by developing a set of templates. An average intensity within each block in a reconstructed picture is calculated (34). The differences of each pixel value from the average output intensity within each block is determined (36). That difference is then multiplied by one of the templates within each block and the results of the multiplications are summed to obtain a calculated result (38). The calculated result is then compared to a threshold to detect an artifact such as ringing or mosquito noise artifacts (40).

Abstract: Methods and systems to configure a receiver based on a channel condition. A system may be implemented to estimate a channel based on PN sequences in a received signal, concurrently equalize a frequency domain representation of the signal with multiple blind adaptive equalizers, and evaluate results of the equalizations to select coefficients of one of the equalizers for further processing. A first equalizer may implement a constant-step-size (CSS) algorithm for a static channel. A second equalizer may implement a variable-step-size (VSS) algorithm for a dynamic channel. Static and dynamic channels may be distinguished based on convergence/divergence of the equalizers, which may be determined from a mean square error estimated from PN sequences in results of the blind equalizations.

Abstract: Methods and systems to modulate and demodulate first and second path bits within sequences of pulses, where each pulse represents first and second path bits and is position-modulated and phase-modulated based on binary values of the corresponding bits, with no more than 1 phase change per N pulses. Position-modulation may be based on first-path bits. Phase-modulation may be based on second-path bits. A modulator first path has an input data rate Q times that of a second path. The first may include an N-bit encoder. The second path may include a Q-bit encoder and an N-bit repetition encoder. A demodulator includes a first path to determine first path bit values based on pulse coordinates integrated over N frames, and a second path to determine second path bit values based on further integration over Q frames.

Abstract: A method for determining an optimal pulse repetition period (PRP) in a system including a wireless transmission device operating in a static physical transmission environment includes providing a first and second injection-locked transmission system (ILT system). The method further includes implementing an algorithm in a microprocessor within the first ILT system. The algorithm includes synchronizing a receiver clock in the second ILT system with the clock of the first ILT system; setting the PRP equal to an impulse duration, the PRP being very short; increasing the PRP until a bit error rate (BER) at the PRP is less than the bit error rate limit; and based on the determining that the BER is less than the bit error rate limit, setting the PRP as the optimal PRP.

Abstract: Frequency domain based methods and systems to perform adaptive multi-mode pre-decoding linear equalization, adaptive channel estimation, turbo equalization, turbo equalization iteration control, and noise variance estimation. An adaptive linear pre-decoder equalizer may include a multi-mode equalizer, which may include a blind equalizer to determine initial equalization coefficients and a decision-directed equalizer to refine the initial equalization coefficients. Turbo equalization may include a dynamic iteration termination criterion and/or a fixed termination criterion. Turbo equalization may be based in part on an adaptive estimated noise variance. Methods and systems disclosed herein may be implemented with respect to single-carrier signals such as digital video broadcast signals.

Abstract: Methods and systems to configure a receiver based on a channel condition. A system may be implemented to estimate a channel based on PN sequences in a received signal, concurrently equalize a frequency domain representation of the signal with multiple blind adaptive equalizers, and evaluate results of the equalizations to select coefficients of one of the equalizers for further processing. A first equalizer may implement a constant-step-size (CSS) algorithm for a static channel. A second equalizer may implement a variable-step-size (VSS) algorithm for a dynamic channel. Static and dynamic channels may be distinguished based on convergence/divergence of the equalizers, which may be determined from a mean square error estimated from PN sequences in results of the blind equalizations.

Abstract: A mobile communication device to equalize a Doppler shifted received signal according to one embodiment is configured to: extract one or more pilot signals from a segment of the received signal; perform Minimum Mean Square Error (MMSE) filtering on the extracted pilot signals, wherein the filter provides estimated pilot signal impulse responses; estimate the amplitudes of one or more path components of the estimated pilot signal impulse responses; estimate the phases of one or more path components of the estimated pilot signal impulse responses; and combine the estimated amplitudes and the estimated phases of the path components of the pilot signal impulse responses, wherein the combination provides an estimated channel impulse response.

Abstract: In accordance with some embodiments, a differential frame may be constructed, for example, by differencing frames or using an error prediction method. More frequently and less frequently used values of a differential frame are identified. Symbols with lower and higher transmission energy are identified. The more frequently used values of the differential frame are mapped to the symbols with lower transmission energy to reduce overall energy consumption.

Abstract: In one embodiment of the invention, a method for controlling video image quality may include receiving digital video data into a buffer that is coupled to a video data encoder. The video data includes multiple tiles. One of the tiles is compressed at a first compression bit size and another tile is compressed at a second compression bit size. The tiles are transmitted to a video data decoder. The first compression bit size is unequal to the second compression bit size.

Abstract: Information to be transmitted may be compressed using range coding for adaptive arithmetic coding with a virtual sliding window. Cost and complexity of coding may be reduced in some cases.

Abstract: An artifact in a discrete cosine transform based decoder output may be detected by developing a set of templates. An average intensity within each block in a reconstructed picture is calculated (34). The differences of each pixel value from the average output intensity within each block is determined (36). That difference is then multiplied by one of the templates within each block and the results of the multiplications are summed to obtain a calculated result (38). The calculated result is then compared to a threshold to detect an artifact such as ringing or mosquito noise artifacts (40).

Abstract: In accordance with some embodiments, a differential frame may be constructed, for example, by differencing frames or using an error prediction method. More frequently and less frequently used values of a differential frame are identified. Symbols with lower and higher transmission energy are identified. The more frequently used values of the differential frame are mapped to the symbols with lower transmission energy to reduce overall energy consumption.

Abstract: In one embodiment of the invention, a method for controlling video image quality may include receiving digital video data into a buffer that is coupled to a video data encoder. The video data includes multiple tiles. One of the tiles is compressed at a first compression bit size and another tile is compressed at a second compression bit size. The tiles are transmitted to a video data decoder. The first compression bit size is unequal to the second compression bit size.