85results about How to "Error propagation" patented technology

A medium streaming distribution system reduces effects of packet loss in a network before the packet reaches radio base station. A medium distribution device for packet-transmits via the base station, a medium stream to the network by a real time transmission protocol. A packet analyzer monitors the packet arriving at the radio base station and transmits feedback Information associated with loss of a packet to the medium distribution device. Based on the feedback from a relay device and a terminal device of the medium stream, the transmission rates from the medium distribution device to the relay device and from the relay device to the terminal device are obtained to provide a greater transmission rate in a surplus band for re-transmission or a forward error correction.

The present invention may be embodied in a method for preventing radial error propagation during self-servowriting of concentric tracks on a magnetic disk in a disk drive. Each written track comprises a plurality of embedded servo sectors that define a circumferential path and that eventually form corresponding servo wedges extending radially across the magnetic disk such that each servo sector t of a track corresponds to a particular servo wedge. In the method comprising, track following is performed along a previously written track and a position error signal is determined for each servo sector. A correction value is recursively estimated for each servo sector of an adjacent track. The correction value is for use in correcting a position error signal determined using the corresponding servo sector of the adjacent track to prevent radial error propagation from previously written track to the adjacent track.

A method is disclosed for writing servo patterns for tracks on a rotating magnetic disk medium of a disk drive. Servo patterns are written on a reference track of the disk medium. Track following of the written servo patterns on the reference track is performed using a servo loop having a closed-loop response. A position error signal is generated for the reference track based on the track following. A correction signal is generated based on the track following using an observer of a one-dimensional state model that is equivalent to a two-dimensional state model of the servo loop. Servo patterns are written on a target track during track following of the reference track. The position error signal of the servo loop is adjusted based on the correction signal to reduce radial error propagation from the reference track to the target track.

A method is disclosed for writing servo patterns for tracks on a rotating magnetic disk medium of a magnetic disk drive. In the method, track following is performed along a reference track, defined by previously written servo burst patterns, using a servo loop having a closed-loop response. A position error signal is generated for the reference track based on the track following. A correction signal is generated based on the track following using an observer of a one-dimensional state model that is equivalent to the two-dimensional state model of the servo loop. Servo patterns are written at a target radial location on the magnetic disk medium during track following of the reference track. The position error signal of the servo loop is adjusted based on the correction signal to reduce radial error propagation from the reference track to the servo burst patterns at the target radial location.

Iterative algorithm methods and systems for slope or gradient-type data is presented for wavefront zonal estimation of regular and irregular pupil shapes. The methods and systems bears universal wavefront estimation matrices that are directly applicable to any pupil shape without the need to set up new matrices. The algorithm consists in first extending the sampling pupil to a larger regular square shape and second extrapolating the sampled slope data outside of the sampling pupil employing Gerchberg-type iterations. Unbiased least-squares wavefront estimation is then performed in the square domain. Results show that the RMS deviation error of the estimated wavefront from the original wavefront can be less than λ / 150 after about twelve iterations and less than λ / 100 (both for λ equal 632.8 nm) within as few as five iterations.

A method of significantly reducing error propagation due to voice packet loss, while still greatly profiting from long-term pitch prediction, is achieved by adaptively limiting the maximum value of the pitch gain for the first pitch cycle within one frame. A speech coding system for encoding a speech signal, wherein said a plurality of speech frames are classified into said a plurality of classes depending on if the first pitch cycle is included in one subframe or several subframes. The pitch gain is set to a value significantly smaller than 1 for the subframes covering first pitch cycle; wherein the pitch gain reduction is compensated by increasing the coded excitation codebook size or adding one more stage of excitation for the subframes covering the first pitch cycle.

A medium streaming distribution system reduces effects of packet loss in a network before the packet reaches radio base station. A medium distribution device for packet-transmits via the base station, a medium stream to the network by a real time transmission protocol. A packet analyzer monitors the packet arriving at the radio base station and transmits feedback information associated with loss of a packet to the medium distribution device. Based on the feedback from a relay device and a terminal device of the medium stream, the transmission rates from the medium distribution device to the relay device and from the relay device to the terminal device are obtained to provide a greater transmission rate in a surplus band for re-transmission or a forward error correction.

Context-based adaptive arithmetic coding and decoding methods and apparatuses with improved coding efficiency and video coding and decoding methods and apparatuses using the same are provided. The method for performing context-based adaptive arithmetic coding on a given slice in an enhancement layer frame of a video signal having a multi-layered structure includes steps of resetting a context model for the given slice to a context model for a base layer slice at the same temporal position as the given slice, arithmetically coding a data symbol of the given slice using the reset context model, and updating the context model based on the value of the arithmetically coded data symbol.

For use in a receiver capable of decoding trellis encoded signals of the type comprising a trellis decoder and a decision feedback equalizer coupled to each path memory output of said trellis decoder, wherein said decision feedback equalizer is capable of obtaining symbol values from each path memory output of said trellis decoder for use as estimates in channel equalization, an apparatus and method is disclosed for reconstructing symbol values from trace back path information stored within said trellis decoder. The apparatus and method of the present invention reconstructs a symbol stream from the trellis decoder using data signal selection circuitry to obtain bit values that represent the reconstructed symbols. In one embodiment of the present invention, each of a plurality of multiplexers selects one of four symbol value inputs to send to a first adaptive filter tap cell in a set of twelve adaptive filter tap cells. The four symbol values represent (1) a symbol at trellis point "t", and (2) a symbol at trellis point "t-12", and (3) a symbol having the value "plus five", and (4) a symbol having the value "minus five."

There is provided a transition mode device and method for use in a predictive-type sound signal codec for producing a transition mode excitation replacing an adaptive codebook excitation in a transition frame and / or a frame following the transition in the sound signal, comprising an input for receiving a codebook index and a transition mode codebook for generating a set of codevectors independent from past excitation. The transition mode codebook is responsive to the index for generating, in the transition frame and / or frame following the transition, one of the codevectors of the set corresponding to the transition mode excitation. There is also provided an encoding device and method and a decoding device and method using the above described transition mode device and method.

Predictive encoding methods, predictive encoders, and digital systems are provided that encode input frames by computing quantized predictive frame parameters for an input frame, recomputing the quantized predictive frame parameters wherein a previous frame is assumed to be erased and frame erasure concealment is used, and encoding the input frame based on the results of the computing and the recomputing. In embodiments of these methods, encoders, and digital systems, two phase codebook search techniques used in the encoding process are provided that compute the predictive parameters in the first phase, and the predictive parameters assuming the prior frame is erased in the second phase. In the second phase, a frame erasure concealment technique is used in the computation of the predictive parameters.

A reproducing device performs decoding by propagating the reliability, and detects micro medium defects to correct the reliability information. The decoder has an internal decoder, external decoder and a defect detector which calculates a moving average value of a soft-input signal, acquires a scaling factor from this, and manipulates the reliability information of the internal decoder. Since micro-defects can be detected accurately and the reliability information of the internal decoder is manipulated, error propagation due to micro defects can be suppressed.

The present invention relates to a method for transmitting video information, in which a bitstream is formed comprising a set of frames comprising macroblocks. At least one switching frame is formed into the bitstream, macroblocks of the switching frame are arranged into a first and a second group of macroblocks, each macroblock of the first group of macroblocks are encoded by a first encoding method to provide a switching point for continuing the transmission of video information with another bitstream formed from the video information; and macroblocks of the second group of macroblocks are encoded by another encoding method. Errors in transmission of video information are reduced by forming at least one SP-encoded frame by predictively encoding the macroblocks; replacing part of the SP-encoded macroblocks with intra encoded blocks; and transmitting the encoded frame containing both predictively and intra encoded macroblocks instead of the SP-encoded frame.

A method and apparatus for encoding a sequence of 32 bit digital data words into a sequence of 33 bit code words in consonance with predetermined minimum zero run length (d) and predetermined maximum zero run length (k) for recording upon a magnetic medium within a magnetic recording channel is disclosed. The method comprises steps of dividing each data word into eight data nibbles, determining whether any data nibble contains all zeros. If no code violation, mapping the eight data nibbles to seven code nibbles and to four bits of a five bit code sub-word and setting a fifth control bit to one. If one or more code violations are present, embedding code violation locations within at least the five bit code sub-word and other code nibbles if necessary and remapping data nibbles ordinarily directed to the code sub-word and nibble locations to code locations otherwise containing the data nibbles determined to be code violations.

An apparatus and a method for interference cancellation in a transmitting end of a multi-antenna system are provided. A precode is generated which maximizes a diversity gain of one or more receive antennas using channel information of the receive antennas to be serviced. Transmit powers of the receive antennas are updated by taking into account a power loss and a shaping loss according to a dirty paper coding. Transmit signals are precoded by updating the precode according to the updated transmit powers. The dirty paper coding is performed on the precoded transmit signals to be transmitted to the receive antennas.

An apparatus for correcting clipping distortion of a receiver system includes: an equalizer which generates a first equalization signal by equalizing a frequency domain clipping signal via a first equalization coefficient correcting a channel distortion, and generates a second equalization signal by equalizing the frequency domain clipping signal via a second equalization coefficient correcting the clipping distortion and the channel distortion; and a signal reconstruction unit which receives the first equalization signal and the second equalization signal from the equalizer, determines a transmission symbol by performing a hard decision with respect to the second equalization, and reconstructs a signal by using an amplitude of the transmission symbol and a phase of the first equalization signal when a level of the amplitude of the transmission symbol is greater than or equal to a reference value.

An apparatus for correcting clipping distortion of a receiver system includes: an equalizer which generates a first equalization signal by equalizing a frequency domain clipping signal via a first equalization coefficient correcting a channel distortion, and generates a second equalization signal by equalizing the frequency domain clipping signal via a second equalization coefficient correcting the clipping distortion and the channel distortion; and a signal reconstruction unit which receives the first equalization signal and the second equalization signal from the equalizer, determines a transmission symbol by performing a hard decision with respect to the second equalization, and reconstructs a signal by using an amplitude of the transmission symbol and a phase of the first equalization signal when a level of the amplitude of the transmission symbol is greater than or equal to a reference value.

A source encoder encodes audio signals into increasing quality layers defined in bit planes. Each bit plane has a data unit that includes a beginning partition having one or more contiguous refinement bits, a second partition having one or more contiguous coded significance bits, a third partition having one or more contiguous sign boundary mark bits, and a fourth partition having one or more contiguous coded sign bits. A channel encoder encodes the bit planes into respective columns containing multiple rows. Unequal error protection coding is provided according to the quality of each layer such that each row has row and column channel protection codes for the respective row and column that correspond to the respective quality layer. For the corresponding row and column, each row contains the row channel protection codes and either the compressed audio data from the respective layer or the column channel protection codes. A server machine can use a network feedback transmission to allocate bits to the source encoder and the channel encoder.

A reproducing device performs decoding by propagating the reliability, and detects micro medium defects to correct the reliability information. The decoder has an internal decoder, external decoder and a defect detector which calculates a moving average value of a soft-input signal, acquires a scaling factor from this, and manipulates the reliability information of the internal decoder. Since micro-defects can be detected accurately and the reliability information of the internal decoder is manipulated, error propagation due to micro defects can be suppressed.

The present invention relates to improvements of predictive encoding / decoding operations performed on a signal which is transmitted over a packet switched network. The signal is encoded on a block by block basis in such way that a block A-B is predictive encoded independently of any preceding blocks. A start state (715) located somewhere between the end boundaries A and B of the block is encoded using any applicable coding method. Both block parts surrounding the start state is then predictive encoded based on the start state and in opposite directions with respect to each other, thereby resulting in a full encoded representation (745) of the block A-B. At the decoding end, corresponding decoding operations are performed.

A scalable audio codec processes, quantizes and encodes audio signals into an embedded audio bitstream of bit-planes each having a data unit. The data unit has a beginning refinement bits partition, a second significance bits partition, a third sign boundary mark bits partition, and a fourth sign bits partition. The second and fourth partitions form a boundary for the third partition. The quantizing uses a variable length coding algorithm. The third partition is an invalid codeword for a predetermined encoding method being used to encode. The codec uses a decoder to decode the embedded audio bitstream of bit-planes using Reversible exponential Golomb (Exp-Golomb) codes in a Reversible Variable Length Code (RVLC) algorithm to produce quantized data of weighted subbands. An inverse quantizer dequantizes the quantized data into audio signals.

A method and apparatus for compensating for non-linearities due to pivot bearing friction when determining embedded runout correction values during partial self-servo write of a disk drive is disclosed. In one embodiment, the disk drive includes a disk surface having a track written thereon and the track has some written-in runout. The written-in runout that is associated with high-frequencies is determined using a first technique. The written-in runout for the track that is associated with low frequencies is determined using a second technique. Results from the two techniques are combined in order to determine embedded runout correction values for the track when partial self-servo writing, in order to reduce error propagation when writing additional tracks.

For use in a receiver capable of decoding trellis encoded signals, there is disclosed an apparatus and method for reducing error propagation in a two stage decision feedback equalizer. The apparatus of the invention comprises a first stage equalizer comprising a first forward equalizer filter, a first decision feedback equalization filter, and a trellis decoder. The apparatus of the invention also comprises a second stage equalizer comprising a second forward equalizer filter and a second feedback equalization filter. The two stage decision feedback equalizer is capable of obtaining symbol values from the trellis decoder and using the symbol values as estimates in channel equalization. In one embodiment of the invention, a two stage decision feedback equalizer is provided in which forward filter coefficients remain constant for the duration of D symbols.

Methods, encoders, and digital systems are provided for predictive encoding of speech parameters in which an input frame is encoded by quantizing a parameter vector of the input frame with a strongly-predictive codebook and a weakly-predictive codebook to obtain a strongly-predictive distortion and a weakly-predictive distortion, adjusting a correlation indicator based on a relative correlation of the input frame to a previous frame, wherein the correlation indicator is indicative of the strength of the correlation of previously encoded frames, and encoding the input frame with the weakly-predictive codebook unless the correlation indicator has reached a correlation threshold.

A system and method for stopping temporal propagation by avoiding using erroneous reference pictures in the streaming of pre-encoded and stored media contents. At least one redundant representation for a picture, referred to as the primary representation, is encoded and stored in a file. When encoding the redundant representation, some reference pictures are not used for inter prediction. In the streaming process, the server maintains the correctness of a list of reference pictures based upon feedback from the device. For the next-to-send picture, selection of a proper representation among the primary and redundant representations is performed such that the sent picture does not use an incorrect picture for inter prediction.

A method, program and system for transmitting from a transmitter to a receiver over a wireless multipie-input-multiple-output channel. In one aspect, the method may comprise encoding precoding information fed back from the receiver to the transmitter according to a differential encoding scheme, and resetting the differential encoding scheme upon detecting a condition. In another aspect, the method may comprises encoding precoding matrices fed back from the receiver to the transmitter relative to a most-probable subset of precoding matrices. In another aspect, the method may comprise transmitting an indication of and / or the size of a preferred subset of precoding matrices for use in the encoding.

The present invention discloses a V-BLAST detection method for a MIMO system, including: a first detecting step for acquiring in sequence the old detection components of a transmitting symbol vector with the optimum ordering-successive interference cancellation detection method; a second detecting step for taking the detection component with the highest space diversity degree among the old detection components as a first new lo detection component, and acquiring in sequence the other new detection components of the transmitting symbol vector in an inverse order of the optimum detection order with the optimum ordering-successive interference cancellation detection method; an outputting step for outputting the first new detection component and the other new is detection components as the final detection result. The method according to the invention employs the outer close loop iteration technology to further reduce inter-layer error propagation of V-BLAST. This method has less complexity.

A data storage system includes an encoder subsystem comprising an error correction code encoder, a modulation encoder, and a precoder, and a decoder subsystem similarly comprising a detector, an inverse precoder, a channel decoder, and an error correction code decoder. The error correction encoder applies an error correction code to the incoming user bit stream, and the modulation encoder applies so-called modulation or constrained coding to the error correction coded bit stream. The precoder applies so-called precoding to the modulation encoded bit stream. However, this precoding is applied to selected portions of the bit stream only. There can also be a permutation step where the bit sequence is permuted after the modulation encoder before precoding is applied by the precoder. The decoder subsystem operates in the inverse manner.

A composite signal including a plurality of component signal streams is processed using QR-decomposition to detect symbols and calculate a decision metric for each of the signal streams (202). Soft serial interference cancellation is performed on the composite signal based on the symbols detected for different ones of the signal streams and a ranking of the signal streams (204). The symbols are re-detected and the decision metric re-calculated for each signal stream based on soft serial interference cancellation results (206). The different decision metric calculations for at least one of the signal streams are compared to determine whether symbol detection is more accurate with or without soft serial interference cancellation (208). The signal streams are decoded using symbols detected based on soft serial interference cancellation results when symbol detection is determined to be more accurate with soft serial interference cancellation (210). Otherwise, the streams are decoded based on the symbols detected using QR-decomposition (210).