290 results about "Channel decoder" patented technology

A multi-channel encoder / decoder scheme additionally preferably generates a waveform-type residual signal. This residual signal is transmitted together with one or more multi-channel parameters to a decoder. In contrast to a purely parametric multi-channel decoder, the enhanced decoder generates a multi-channel output signal having an improved output quality because of the additional residual signal.

An enhanced 8-VSB reception system and E8-VSB data demultiplexing method, by which an E8-VSB signal can be stably received as well as a previous ATSC 8VSB signal, is disclosed. Herein, the enhanced data are coded at ½ code rate and ¼ code rate in the new E8-VSB transmission system compatible with the conventional ATSC 8VSB system, respectively. The ½ and ¼ enhanced data are multiplexed by 164-byte packet unit according to the previously determined multiplexing format and further pre-processed to output as the format of the MPEG transport packet. And, the pre-processed enhanced data and the main data are multiplexed again by 188-byte packet unit according to the previously determined multiplexing format. The E8-VSB map information, which was inserted in the field sync section in the E8-VSB transmission system to be transmitted, is extracted to generate the information indicating the attributes of the respective E8-VSB data. The normal data, ½ enhanced data, and ½ enhanced data are separated from each other to be decoded in the channel decoder.

A data detection and decoding system includes a SOVA channel detector that uses single parity (SOVASP) to improve the accuracy with which the detector estimates bits. Each column or row read back from the read channel constitutes a code word and each code word is encoded to satisfy single parity. Because the SOVASP channel detector detects whether each code word satisfies single parity, it is unnecessary to use both a column decoder and a row decoder in the channel decoder. Either the row decoder or the column decoder can be eliminated depending on whether bits are read back on a column-by-column basis or on a row-by-row basis. This reduction in components reduces hardware complexity and improves system performance. The output of the row or column decoder is received by a second detector that processes the output received from the decoder to recover the original information bits.

A multi-channel decoder for generating a binaural signal from a downmix signal using upmix rule information on an energy-error introducing upmix rule for calculating a gain factor based on the upmix rule information and characteristics of head related transfer function based filters corresponding to upmix channels. The one or more gain factors are used by a filter processor for filtering the downmix signal so that an energy corrected binaural signal having a left binaural channel and a right binaural channel is obtained.

The present invention relates to improved multiple access communications. In one form, the invention relates to an improved signal processing method and apparatus for an iterative method of determining the reception of a signal in a multi user packet based wireless OFDM (Orthogonal Frequency Division Multiplexing) communication system. In other forms the present invention provides recursive filtering for joint iterative decoding in a variety of systems and functions such as linear multiple access channel decoders, iterative equalisation, iterative joint channel estimation and detection / decoding, iterative space-time processing, iterative multi user interference cancellation and iterative demodulation. In one particular form the present invention provides an iterative decoding circuit for a wireless multiuser communications receiver comprising a first signal processing means for receiving at least one received signal, said first signal processing means comprising at least two linear iterative filters such that the first linear iterative filter provides an estimate of a selected received signal to an estimated signal output and a second linear iterative filter provides estimates of at least one other received signal, delayed by one iteration cycle, to an input of said first linear iterative filter, a second signal processing means for receiving the estimated signal output of the first linear iterative filter and providing a further received signal estimate to the input of the first signal processing means in a succeeding iteration cycle of the decoding circuit.

A data transmission system is provided for transmitting user data to and receiving data from a communication channel, including a parity check matrix having M tiers, wherein M≦2, Dmin=2*M for M=1 . . . 3 or 2*M≦Dmin≦6 for M>3, wherein Dmin is the minimum Hamming distance, tc=M, wherein tc is the column weight, and cycle−4=0. A linear block encoder encodes the user data in response to the parity check matrix, and a transmitter transmits an output of the linear block encoder to the communication channel. A soft channel decoder decodes data, and a soft linear block code decoder to decode data decoded by the soft channel decoder in response to the parity check matrix.

A system for producing multiple concurrent real-time video streams from stored MPEG video clips includes a video server and at least one MPEG decoder array. The decoder array has multiple decoder pairs, each pair having a video switch for switching from one decoder in the pair to the other at a specified time. Switching may occur from a specified Out-point frame to a specified In-point frame, and the specified frames can be any frame type at any location in the group of pictures (GOP) structure. In a preferred construction, the video server has a controller server linked to a series of data mover computers, each controlling one or more respective decoder arrays. The data mover computers use a control protocol to control the decoder arrays, and each decoder uses a data protocol to request data from a respective data mover computer.

In a multi-channel encoder generating several different parameter sets for reconstructing a multi-channel output signal using at least one transmission channel, the data stream is written such that the two parameter sets are decodable independently of each other. Thus, a multi-channel decoder is enabled to skip a parameter set which is marked as optional and / or has a higher version number when reading the data stream and still to perform a valid multi-channel reconstruction using a data set marked as mandatory or a data set having a sufficiently low version number. This achieves a flexible encoder / decoder concept suitable for future updates characterized by backward compatibility and reliability.

A data detection and decoding system includes a SOVA channel detector that uses single parity (SOVASP) to improve the accuracy with which the detector estimates bits. Each column or row read back from the read channel constitutes a code word and each code word is encoded to satisfy single parity. Because the SOVASP channel detector detects whether each code word satisfies single parity, it is unnecessary to use both a column decoder and a row decoder in the channel decoder. Either the row decoder or the column decoder can be eliminated depending on whether bits are read back on a column-by-column basis or on a row-by-row basis. This reduction in components reduces hardware complexity and improves system performance. The output of the row or column decoder is received by a second detector that processes the output received from the decoder to recover the original information bits.

An apparatus and method are provided for normalizing input soft metric to a channel decoder in a wireless communication system. A demapper generates soft metric using an in-phase component (Xk) and a quadrature component (Yk) of a received modulated symbol (Rk), a channel fading coefficient (gk) and a constant value (c) defined by a modulation order of the received modulated symbol. A normalizer receives the soft metric, computes a normalized log likelihood ratio (LLR) by multiplying the soft metric by a ratio of the constant value to a noise variance value, transforms the normalized LLR into a desired range and a desired number of bits, and outputs an input LLR of the channel decoder.

A transmitter is provided for transmitting data to a communication channel and a receiver receives the data from the communication channel. The transmitter comprises an encoder to encode data and a linear block encoder to encode data encoded by the encoder. The receiver comprises a soft channel decoder to decode the data, and a soft linear block code decoder to decode data decoded by the soft channel decoder. In the first iteration, the soft channel decoder decodes data received by the receiver. In succeeding iterations, the soft channel decoder decodes the data received by the receiver and utilizes information from the soft linear block decoder from an immediate preceding iteration. A decision circuit selects an output of the soft linear block decoder if an evaluated criterion is less than a threshold, or an output of the soft channel decoder if the evaluated criterion is greater than the threshold. A decoder decodes an output of the threshold check circuit.

An enhanced 8-VSB reception system and E8-VSB data demultiplexing method, by which an E8-VSB signal can be stably received as well as a previous ATSC 8VSB signal, is disclosed. Herein, the enhanced data are coded at ½ code rate and ¼ code rate in the new E8-VSB transmission system compatible with the conventional ATSC 8VSB system, respectively. The ½ and ¼ enhanced data are multiplexed by 164-byte packet unit according to the previously determined multiplexing format and further pre-processed to output as the format of the MPEG transport packet. And, the pre-processed enhanced data and the main data are multiplexed again by 188-byte packet unit according to the previously determined multiplexing format. The E8-VSB map information, which was inserted in the field sync section in the E8-VSB transmission system to be transmitted, is extracted to generate the information indicating the attributes of the respective E8-VSB data. The normal data, ½ enhanced data, and ½ enhanced data are separated from each other to be decoded in the channel decoder.

The present invention relates to improved multiple access communications. In one form, the invention relates to an improved signal processing method and apparatus for an iterative method of determining the reception of a signal in a multi user packet based wireless OFDM (Orthogonal Frequency Division Multiplexing) communication system. In other forms the present invention provides recursive filtering for joint iterative decoding in a variety of systems and functions such as linear multiple access channel decoders, iterative equalisation, iterative joint channel estimation and detection / decoding, iterative space-time processing, iterative multi user interference cancellation and iterative demodulation. In one particular form the present invention provides an iterative decoding circuit for a wireless multiuser communications receiver comprising a first signal processing means for receiving at least one received signal, said first signal processing means comprising at least two linear iterative filters such that the first linear iterative filter provides an estimate of a selected received signal to an estimated signal output and a second linear iterative filter provides estimates of at least one other received signal, delayed by one iteration cycle, to an input of said first linear iterative filter, a second signal processing means for receiving the estimated signal output of the first linear iterative filter and providing a further received signal estimate to the input of the first signal processing means in a succeeding iteration cycle of the decoding circuit.

An embodiment of the present invention provides a wireless telephone including a receiver module, a channel decoder, a speech decoder, and a speaker. The receiver module receives a plurality of versions of a voice signal, wherein each version of the voice signal comprises a plurality of speech frames. The channel decoder is configured to decode a speech parameter associated with a first speech frame from a first version of the voice signal, wherein decoding the speech parameter includes selecting an optimal bit sequence from a plurality of candidate bit sequences and wherein the selection of the optimal bit sequence is based in part on a second speech frame from a second version of the voice signal. The speech decoder decodes at least one of the first or second versions of the voice signal based on the speech parameter to generate an output signal. The speaker receives the output signal and produces a sound pressure wave corresponding thereto.

Systems and methods for decoding neural and / or electromyographic signals are provided. A system can include at least one single channel decoder. Optionally, the system can include a demixer in operable communication with the single channel decoders. Each single channel decoder can include a filter to attenuate noise and sharpen spikes in the neural and / or electromyographic signals, a detection function to identify spikes, and a demodulator to get a real-time estimate of motor intent.

An apparatus for receiving data through channels in a communication system including a first channel for transmitting control information related to a second channel and the second channel for transmitting packet data, the apparatus comprising: a first channel decoder for decoding the first channel and outputting control information; an active Walsh mask storing section for storing a Walsh mask acquired from the control information; a second channel decoder for decoding the second channel using the Walsh mask stored in the active Walsh mask storing section and outputting a decoding result; and a control unit for changing the Walsh mask to a previous Walsh mask if a Walsh mask error is determined according the decoding result.

Channel coding is used on the forward link of a CDMA cellular telephone network to allow the CDMA mobile channel decoder to perform error correction. On a wireless link, channel code performance is improved by providing the channel decoder with an estimate of the reliability of each received symbol. This reliability information is typically the ratio of desired signal energy to interference plus noise variance at the channel decoder input. This invention improves CDMA mobile channel decoder performance using a new technique for calculating more accurate estimates of the signal to interference plus noise ratio at the input of the mobile channel decoder.

A disk drive using a read / write channel including an iteration decoder for performing iterative decoding processing is disclosed. The iteration decoder has an RLL error detector for detecting a burst error portion from an LLR group output from the channel decoder, and an LLR adjuster. The LLR adjuster makes adjustment by reducing the value of the LLR group corresponding to the detected burst error portion.

From potential symbol combinations transmitted from a transmitter, Euclidean distances between the received signals and the symbol vectors are determined in light of the corresponding channel responses and stored in a Euclidean distance table, from which the smallest Euclidean distance is selected as a hard decision. The hard decision is used to find a bit vector corresponding to the estimated symbol vector associated with the hard decision. For each bit in the bit vector, a reduced Euclidean distance table is created to include only Euclidean distances associated with a competing bit associated with the hard decision. The minimum Euclidean distance from each reduced Euclidean distance table becomes a soft demapping decision for a corresponding bit. Log likelihood ratios for each bit are determined by the difference between the hard decision and respective soft demapping decisions. The differences are provided to a channel decoder to recover the originally transmitted bits.

The invention discloses a multi-user network coding communication method with a high speed parallel encoding and decoding structure, which comprises the following steps: in a wireless relay network, multiple accessed user information is integrally interweaved by a relay node, serial / parallel conversion is carried out on the interweaved sequence, multiple groups of converted parallel data are input to a high speed parallel encoder to be encoded, and finally encoded data is broadcasted, thus realizing network encoding. A base station carries out teration decoding by means of a combined network-channel decoder according to original data broadcasted by users and data obtained by network encoding and channel encoding and forwarded by the relay node to obtain the original information of the users. The decoder of the base station comprises two parallel decoder groups, i.e. a user decoder group and a relay decoder group; iteration decoding is realized through transmitting soft information between two parallel decoder groups, thus not only recovering the original information of all accessed users but also improving decoding reliability and reducing decoding time delay. By adopting the method, the relay uplink transmission efficiency and the quality of transmission signal are improved.

The invention provides a code modulation method and system adopting a Raptor-like Irregular QC-LDPC code. The code modulation method includes the steps that the code modulation system receives input information bits; LDPC channel coding is conducted on the information bits according to a check matrix of the Raptor-like Irregular QC-LDPC code to generate coding bits; bit mapping is conducted on the coding bits to obtain mapping bits; constellation mapping is conducted on the mapping bits to obtain constellation mapping symbols, and the constellation mapping symbols pass through an equivalent transmission channel to obtain receiving symbols; bit soft de-interleaving is conducted on extrinsic information of the mapping bits to generate prior information of the coding bits; the prior information of the coding bits is decoded to obtain the extrinsic information of the coding bits; bit soft interleaving is conducted on the extrinsic information of the coding bits to generate the prior information of the mapping bits, and LDPC decoding results are output after multiple iterations. The code modulation method improves the flexibility of a communication system, simplifies a realization method of a channel decoder applied to a variety of services and facilitates improvement of the handling capacity and the expansibility of a code modulation system.

An apparatus and method are provided for normalizing input soft metric to a channel decoder in a wireless communication system. A demapper generates soft metric using an in-phase component (Xk) and a quadrature component (Yk) of a received modulated symbol (Rk), a channel fading coefficient (gk) and a constant value (c) defined by a modulation order of the received modulated symbol. A normalizer receives the soft metric, computes a normalized log likelihood ratio (LLR) by multiplying the soft metric by a ratio of the constant value to a noise variance value, transforms the normalized LLR into a desired range and a desired number of bits, and outputs an input LLR of the channel decoder.

A lossless encoder and decoder are provided for transmitting a multichannel signal on a medium such as DVD-Audio. The encoder accepts additionally a downmix specification and splits the encoded stream into two substreams, such that a two-channel decoder of meagre computational power can implement the downmix specification by decoding one substream, while a multichannel decoder can decode the original multichannel signal losslessly using both substreams. Further features provide for efficient implementation on 24-bit processors, for confirmation of lossless reproduction to the user, and for benign behaviour in the case of downmix specifications that result in overload. The principle is also extended to mixed-rate signals, where for example some input channels are sampled at 48 kHz and some are sampled at 96 kHz.

An apparatus and method for receiving a packet data control channel in a mobile communication system that transmits packet data and has the packet data control channel for transmitting control information related to transmission of packet data are provided. A receiver receives and despreads a signal on the packet data channel and a signal on the packet data control channel, separately outputs the signals, and estimates a noise of a received signal. A signal level detector receives a noise estimation value and samples of the packet data control channel signal from the receiver, and outputs a validity signal for detecting whether information is received over the packet data control channel. A packet data control channel decoder decodes the packet data control channel signal if the validity signal received from the signal level detector is valid.

A communication relay apparatus for providing a network-encoded information unit sequence comprises a first channel decoder which is configured to supervise a first wireless channel, to receive a first channel-encoded sequence of information units from a first data source via the first wireless channel and to decode the first channel-encoded sequence of information units to obtain a first decoded sequence of information units. Furthermore, the communication relay apparatus comprises a second channel decoder which is configured to supervise a second wireless channel, to receive a second channel-encoded sequence of information units from a second data source via the second wireless channel and to decode the second channel-encoded sequence of information units to obtain a second decoded sequence of information units, the first and second wireless channels being different from each other. Finally, the communication relay apparatus comprises a network-encoder which is configured to encode information of the first and second decoded sequences of information units into the network-encoded information unit sequence and wherein the network-encoder is further configured to wirelessly transmit the network-encoded information unit sequence to a data sink.

A lossless encoder and decoder are provided for transmitting a multichannel signal on a medium such as DVD-Audio. The encoder accepts additionally a downmix specification and splits the encoded stream into two substreams, such that a two-channel decoder of meagre computational power can implement the downmix specification by decoding one substream, while a multichannel decoder can decode the original multichannel signal losslessly using both substreams. Further features provide for efficient implementation on 24-bit processors, for confirmation of lossless reproduction to the user, and for benign behaviour in the case of downmix specifications that result in overload. The principle is also extended to mixed-rate signals, where for example some input channels are sampled at 48 kHz and some are sampled at 96 kHz

The invention discloses a system and a method for realizing iterative timing synchronization of a continuous phase modulation (CMP) signal; the system is provided with a sender, and is composed of a maximum likelihood detector, a de-interleaver, a channel decoder and an information destination which are connected in order, and an interleaver which is used for interleaving an output signal of the channel decoder and feeding back the interleaved output signal to the maximum likelihood detector; a built-up circuit of the maximum likelihood detector comprises a match filter set, a demodulator, and a timing synchronization loop circuit arranged between the match filter set and the demodulator; a detecting method based on a maximum likelihood criterion is used for demodulating the received CPM signal, detecting and computing a timing error value and adjusting the time delay, and outputting a bit likelihood ratio of each symbol. Based on a timing error detecting method of the maximum likelihood criterion, a soft information assistance fed back by the channel decoder is used for realizing the timing synchronization to obtain an accurate timing deviation estimation; meanwhile, an iterativeprocess is used between the demodulation and the decoding to maximally improve an error bit ratio of the system; and the system and method for realizing iterative timing synchronization of the CMP signal can be applied in long-distance communication with the requirement of high performance.

Disclosed is a system and method for channel decoding speech frames in a receiver capable of multiple (M) codec modes, wherein channel encoded speech frames include an inband bit portion and a speech portion. An inband bit decoder decodes the inband bit portion (700) of a received frame to obtain confidence levels associated with each of the M codec modes. Using these confidence levels, the codec modes are ordered from most to least likely. The speech frame is then decoded by a channel decoder using the most likely codec mode (704). A frame determination check (720) is performed to determine the quality of the decoded speech frame. If the decoded speech frame is determined to be of poor quality, then the channel decoding process is repeated using the next most likely codec mode (736) corresponding to the next highest inband bit decoding confidence level. This process is repeated until a good speech frame is decoded or some exit criteria is reached.

A configurable cellular terminal engine (CTE) in accordance with an exemplary embodiment of this invention is configurable by an external agent (e.g., microcontroller, DSP, or state machine) to suit the particular requirements of different spread spectrum systems. In an exemplary embodiment, the CTE comprises on a chipset a modem unit and a channel codec unit. The modem unit has a front end unit for coupling to an antenna; a matched filter searchers unit coupled at least to the front end unit; a searchers unit coupled to at least the front end unit; a finger processing unit coupled to the front end unit; a parameter estimation processor unit coupled to at least the finger processing unit and the searchers unit; and a transmitter unit. The channel codec unit has a channel decoder unit coupled at least to the finger processing unit; and a channel encoder coupled at least to the transmitter unit.