Abstract: A system for mitigating impairment in a communication system includes a delay block, a signal level block, a moving average window block, an impulse noise detection block, and a combiner. The delay block receives and delays each chip of a plurality of chips in a spreading interval. The signal level block determines a signal level of each chip of the plurality of chips in the spreading interval. The moving average window block determines a composite signal level for a chip window corresponding to the chip. The impulse noise detection block receives the signal level, receives the composite signal level, and produces an erasure indication for each chip of the plurality of chips of the corresponding chip window. The combiner erases chips of the plurality of chips of the spreading interval based upon the erasure indication.

Abstract: A communication system performs burst noise cancellation. A transmitter produces and transmits a spread signal that comprises at least one known-value symbol spread by a plurality of non data-carrying orthogonal codes and data symbols spread by at least one data-carrying orthogonal code. The transmitter transmits the spread signal across a communication link that introduces burst noise. A burst noise detector determines burst noise affected chips of the orthogonal codes. A weight computation functional block calculates a plurality of complex-valued combining weights based upon the burst noise affected chips. A vector de-spreader and a linear combiner operate in combination to use the plurality of non data-carrying orthogonal codes, the at least one data-carrying orthogonal code, and the plurality of complex-valued combining weights to de-spread the received spread signal to produce the data symbols with the burst noise substantially removed.

Abstract: A system for mitigating impairment in a communication system includes a delay block, a signal level block, a moving average window block, an impulse noise detection block, and a combiner. The delay block receives and delays each chip of a plurality of chips in a spreading interval. The signal level block determines a signal level of each chip of the plurality of chips in the spreading interval. The moving average window block determines a composite signal level for a chip window corresponding to the chip. The impulse noise detection block receives the signal level, receives the composite signal level, and produces an erasure indication for each chip of the plurality of chips of the corresponding chip window. The combiner erases chips of the plurality of chips of the spreading interval based upon the erasure indication.

Abstract: Successive interference canceling for CDMA. ICI may result from a signal's multi-path effects, or by filtering/suppression of some of the component energy of the signaling waveforms. Energy component attenuation destroys orthogonality of CDMA symbols thereby causing ICI. An ICF suppresses frequency domain portions (attenuates ingress), but also introduces ICI. Following the ICF, the signal is de-spread, sliced, re-spread and convolved with the ICF echoes (except first tap echoes). Convolving re-spread hard decisions with delayed ICF taps is equivalent to partially re-modulating the first-pass hard decisions to efficiently “add-back-in” the signal energy which was blanked/subtracted by the ICF. Alternatively, parameter estimation de-rotates and re-rotates soft symbols and hard decisions, respectively, compensating for undesirable symbol rotation. The convolved signal is subtracted from a delayed version of the ICF output signal.

Abstract: A system and method of transmitting video in a time division multiplexing (TDM) system, wherein the method comprises identifying a video reference frame from a series of video frames; encoding a difference between the video reference frame and a video non-reference frame; placing the video reference frame at a beginning of a data burst; transmitting the series of video frames and the data burst from a transmitter to a mobile TV receiver; and the mobile TV receiver immediately locating the video reference frame upon receipt of the data burst. The method may further comprise the mobile TV receiver decoding the series of video frames. Additionally, the placing process results in a substantially non-existent channel switching delay in the mobile TV receiver. Moreover, the method may further comprise placing exactly one video reference frame at the beginning of the data burst. Preferably, the TDM system comprises a mobile TV system.

Abstract: A system for mitigating impairment in a communication system includes a delay block, a signal level block, a moving average window block, an impulse noise detection block, and a combiner. The delay block receives and delays each chip of a plurality of chips in a spreading interval. The signal level block determines a signal level of each chip of the plurality of chips in the spreading interval. The moving average window block determines a composite signal level for a chip window corresponding to the chip. The impulse noise detection block receives the signal level, receives the composite signal level, and produces an erasure indication for each chip of the plurality of chips of the corresponding chip window. The combiner erases chips of the plurality of chips of the spreading interval based upon the erasure indication.

Abstract: Sparse channel equalization may be achieved by receiving a signal via a multi-path communication channel. The equalization then continues by extracting sparse information regarding the multiple path communication channel from the signal. Such sparse information generally indicates the position of the signals received via each of the multiple paths. The equalization then continues by estimating a channel response of the multiple path communication channel based on the sparse information. The equalization then continues by generating equalization taps (or coefficients) based on the channel response. The equalization then continues by equalizing the signal based on the equalization taps.

Abstract: A MPE-FEC memory chip and method for use in a DVB-H receiver, wherein the memory chip comprises a TS demux; a RS decoder; a system bus; and a RAM unit adapted to simultaneously interface to the TS demux, the RS decoder, and the system bus through time-multiplexing, wherein the RAM unit is adapted to (i) access multiple-words per clock cycle, and (ii) cache write and read accesses to reduce memory access from the TS demux and the system bus, and wherein the RAM unit is adapted to be clocked at a speed higher than an interfacing data-path to increase an effective throughput of the RAM unit. The RAM unit may comprise multiple RAM sub units, wherein while a first RAM sub unit is clock gated, the remaining multiple RAM sub units are accessible.

Abstract: Location cache memory architectures that only require 32 Kbits or less per frame to store erasure information with simple address mapping to the main MPE-FEC RAM for easy column-wise and row-wise access. Alternative architectures are designed to greatly reduce the size and logic complexity of the MPE-FEC erasure cache memory. Two architectures reduce the erasure cache size down to 32 Kbits and 28 Kbits, correspondingly, without introducing additional erasure locations, while another architecture further reduces the required memory size down to 16K, 8K, 4K, or 2K bits with a slight increase in the total erasure locations. All architectures group the data in MPE-FEC frame memory into blocks of 2M consecutive bytes and use one or a few bits to store the erasure status in each block, thereby, greatly reducing the required cache memory size.

Abstract: A system for mitigating impairment in a communication system includes a delay block, a signal level block, a moving average window block, an impulse noise detection block, and a combiner. The delay block receives and delays each chip of a plurality of chips in a spreading interval. The signal level block determines a signal level of each chip of the plurality of chips in the spreading interval. The moving average window block determines a composite signal level for a chip window corresponding to the chip. The impulse noise detection block receives the signal level, receives the composite signal level, and produces an erasure indication for each chip of the plurality of chips of the corresponding chip window. The combiner erases chips of the plurality of chips of the spreading interval based upon the erasure indication.

Abstract: A system and method of performing re-synchronization for a Digital Video Broadcasting over Handheld (DVB-H) receiver, wherein the method comprises performing a time division multiplexing (TDM) data burst transmission sequence on bits of data received by the DVB-H receiver; performing a data bit re-synchronization sequence on the DVB-H receiver; removing an on-chip timer and internal state registers in the DVB-H receiver; and allowing the DVB-H receiver to power off in between receipt of data bursts. Preferably, the removing process reduces the time to perform the re-synchronization in the DVB-H receiver. Preferably, the data bit re-synchronization sequence comprises performing an automatic gain control (AGC) lock process; performing a mode and guard detecting process; performing a frequency offset estimation process; performing a transmit parameter signaling (TPS) detection process; performing a timing and carrier loop lock process; and performing an equalizer delay process.

Abstract: A system and method of performing re-synchronization for a Digital Video Broadcasting over Handheld (DVB-H) receiver comprises performing a time division multiplexing (TDM) data burst transmission sequence on bits of data received by the DVB-H receiver; performing a data bit re-synchronization sequence on the DVB-H receiver; and reducing a re-acquisition time at every stage of the data bit re-synchronization sequence, wherein the reducing process results in a reduction in the time to perform the re-synchronization for the DVB-H receiver, wherein the reduction in the time to perform the re-synchronization for the DVB-H receiver is greater than one-half of the time required to perform the re-synchronization for the DVB-H receiver absent the reducing of the re-acquisition time at every stage of the data bit re-synchronization sequence.

Abstract: A communication system performs burst noise cancellation. A transmitter produces and transmits a spread signal that comprises at least one known-value symbol spread by a plurality of non data-carrying orthogonal codes and data symbols spread by at least one data-carrying orthogonal code. The transmitter transmits the spread signal across a communication link that introduces burst noise. A burst noise detector determines burst noise affected chips of the orthogonal codes. A weight computation functional block calculates a plurality of complex-valued combining weights based upon the burst noise affected chips. A vector de-spreader and a linear combiner operate in combination to use the plurality of non data-carrying orthogonal codes, the at least one data-carrying orthogonal code, and the plurality of complex-valued combining weights to de-spread the received spread signal to produce the data symbols with the burst noise substantially removed.

Abstract: Outer code covered synchronous code division multiple access for cable modem (CM) channels. Outer pseudo-noise (PN) code is employed, along with orthogonal codes (OCs), to spread CM signals thereby mitigating inter-code-interference (ICI) effects caused by residual multi-path propagation within CM communication systems. The added and implemented PN sequences have relatively good autocorrelation properties (when compared to the autocorrelation properties of the OCs) that mask the possible bad autocorrelation and/or cross-correlation properties of the OCs. This outer-code covered PN coding, along with the OC coding, enables much better performance in the presence of residual multi-path. The PN code's added complexity is very minimal as the PN may use the same chip rate of the orthogonal code while providing for better performance in the presence of residual multi-path components.

Abstract: Successive interference canceling for CDMA. ICI may result from a signal's multi-path effects, or by filtering/suppression of some of the component energy of the signaling waveforms. Energy component attenuation destroys orthogonality of CDMA symbols thereby causing ICI. An ICF suppresses frequency domain portions (attenuates ingress), but also introduces ICI. Following the ICF, the signal is de-spread, sliced, re-spread and convolved with the ICF echoes (except first tap echoes). Convolving re-spread hard decisions with delayed ICF taps is equivalent to partially re-modulating the first-pass hard decisions to efficiently “add-back-in” the signal energy which was blanked/subtracted by the ICF. Alternatively, parameter estimation de-rotates and re-rotates soft symbols and hard decisions, respectively, compensating for undesirable symbol rotation. The convolved signal is subtracted from a delayed version of the ICF output signal.

Abstract: A communication system performs burst noise cancellation. A transmitter produces and transmits a spread signal that comprises at least one known-value symbol spread by a plurality of non data-carrying orthogonal codes and data symbols spread by at least one data-carrying orthogonal code. The transmitter transmits the spread signal across a communication link that introduces burst noise. A burst noise detector determines burst noise affected chips of the orthogonal codes. A weight computation functional block calculates a plurality of complex-valued combining weights based upon the burst noise affected chips. A vector de-spreader and a linear combiner operate in combination to use the plurality of non data-carrying orthogonal codes, the at least one data-carrying orthogonal code, and the plurality of complex-valued combining weights to de-spread the received spread signal to produce the data symbols with the burst noise substantially removed.

Abstract: A system for mitigating impairment in a communication system includes a delay block, a signal level block, a moving average window block, an impulse noise detection block, and a combiner. The delay block receives and delays each chip of a plurality of chips in a spreading interval. The signal level block determines a signal level of each chip of the plurality of chips in the spreading interval. The moving average window block determines a composite signal level for a chip window corresponding to the chip. The impulse noise detection block receives the signal level, receives the composite signal level, and produces an erasure indication for each chip of the plurality of chips of the corresponding chip window. The combiner erases chips of the plurality of chips of the spreading interval based upon the erasure indication.

Abstract: Successive interference canceling for CDMA. ICI may result from a signal's multi-path effects, or by filtering/suppression of some of the component energy of the signaling waveforms. Energy component attenuation destroys orthogonality of CDMA symbols thereby causing ICI. An ICF suppresses frequency domain portions(attenuates ingress), but also introduces ICI. Following the ICF, the signal is de-spread sliced, re-spread and convolved with the ICF echoes (except first tap echoes). Convolving re-spread hard decisions with delayed ICF taps is equivalent to partially re-modulating the first-pass hard decisions to efficiently “add-back-in” the signal energy which was blanked/subtracted by the ICF. Alternatively, parameter estimation de-rotates and re-rotates soft symbols and hard decisions, respectively, compensating for undesirable symbol rotation. The convolved signal is subtracted from a delayed version of the ICF output signal.

Abstract: Carrier frequency offset (CFO) estimation from preamble symbols. Any communication receiver may be adapted to perform the CFO estimation. The CFO estimation is performed using a low complexity, high accuracy CFO estimation method. The operation may be described as follows: each element of a received sequence is divided by the corresponding preamble element, the resulting sequence is divided into N subgroups, and each subgroup is then averaged. The phase differential of the resulting sequence is computed, averaged, and used to compute an estimate of the carrier frequency offset. This approach to performing CFO estimation is of relatively high estimation accuracy and of relatively low computational complexity.

Abstract: A communication device constructed according to the present invention detects impulse noise in a preamble sequence. In detecting impulse noise in the preamble sequence the communication device first receive a preamble sequence that includes a plurality of preamble symbols. The communication device then divides the plurality of preamble symbols by at least one known preamble symbol to produce a plurality of preamble gains and/or a plurality of preamble phases corresponding to the plurality of preamble symbols. Finally, the communication device determines, based upon the plurality of preamble gains and/or the plurality of preamble phases, that at least one preamble symbol has been adversely affected by a impulse noise. The communication device may discard at least one preamble symbol that has been adversely affected by impulse noise from the plurality of preamble symbols.