2206 results about "Forward error correction" patented technology

A digital television (DTV) transmitter and a method of processing data in the DTV transmitter / receiver are disclosed. In the DTV transmitter, a pre-processor pre-processes the enhanced data by coding the enhanced data for forward error correction (FEC) and expanding the FEC-coded data. A packet formatter generates one or more groups of enhanced data packets, each enhanced data packet including the pre-processed enhanced data and known data, wherein the data formatter adds burst time information into each group of enhanced data packets. And, a packet multiplexer generates at least one burst of enhanced data by multiplexing the one or more groups of enhanced data packets with at least one main data packet including the main data, each burst of enhanced data including at least one group of enhanced data packets.

A digital television (DTV) transmitter and a method of coding data in the DTV transmitter method are disclosed. A pre-processes enhanced data by coding the enhanced data for forward error correction (FEC) and expanding the FEC-coded enhanced data. A data formatter generates enhanced data packets including the pre-processed enhanced data and inserting known data to at least one of the enhanced data packets. A first multiplexer multiplexes main data packets with the enhanced data packets, and a data randomizer randomizes the multiplexed data packets. A Reed-Solomon (RS) encoder RS-codes the randomized data packets by adding first parity data, and a data interleaver interleaves the RS-coded data packets. A trellis encoder trellis-encodes the interleaved data packets, wherein the trellis encoder may be initialized when a known data sequence is inputted thereto.

A hybrid ARQ scheme is used incremental data packet combining. In an example embodiment, the hybrid ARQ scheme with incremental data packet combining employs three feedback signaling commands: ACK, NACK, and LOST. Using these three feedback commands, the hybrid ARQ scheme with incremental data packet combining provides both robustness and good performance. This scheme is particularly advantageous in communication systems with unreliable communication channels, e.g., a fading radio channel, where forward error correction (FEC) codes are used and some of the code symbols are more important than other code symbols. Benefits include increased throughput and decreased delay of the packet data communication.

Apparatus for recording and collecting usage and other statistical data from components of a cable data network comprises a network manager for maintaining and collecting the statistics. Internet protocol addresses are associated with components of the network. The component maintains a software agent that manages a statistics database. Responsive to a manager request generated at a service provider defined time interval, the component software agent provides the usage statistics to the network manager in real-time during an Internet session with a host. When the host to Internet or other data connection is torn down due to failure, disconnect or inactivity time-out, remaining usage statistics data is collected and the session duration updated with the time of tear down. Usage statistics collected include the amount of data transferred to / from a host, the amount of data that is discarded due to insufficient resource capacity and amount of data that cannot be corrected despite forward error correction used in a downstream high capacity channel to the host. Data traps may be defined and downloaded to components of the network for implementation. As a result, billing of users of the cable data network can be usage sensitive and determined based on actual data transferred (including credit given for errored data) and / or time sensitive based on session duration.

Using a transformation based, at least in part, on a non-simple orthogonal matrix, data may be transmitted over a data bus in a manner that is resilient to one or more types of signal noise, that does not require a common reference at the transmission and acquisition points, and / or that has a pin-efficiency that is greater than 50% and may approach that of single-ended signaling. Such transformations may be implemented in hardware in an efficient manner. The transformation may be combined with methods from forward error correction to lower the required transmission power.

A method for controlling errors in a wireless link layer using a simultaneous multiple copy scheme and an adaptive forward error correction (FEC) scheme in a wideband wireless communication is provided. The method for controlling errors in a link layer in wideband wireless communication using an automatic repeat request (ARQ) scheme, in which a wideband wireless channel is used for communication between a first node and a second node, includes the steps of (a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel using the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel, and transmitting a cell, in which a forward error correction (FEC) code having an encoding ratio that varies depending on the estimated error ratio is included in a protocol data unit (PDU) of a wireless link layer, through the forward channel and (b) re-transmitting the copy of a cell transmitted in the step (a), when feedback information that indicates that an error exists in the cell transmitted in the step (a) is received through the backward channel. It is possible to reduce the number of times of re-transmission by improving the probability of correcting forward errors using more error controlling bits as the state of the channel is worse and to minimize the waste of resources using less error controlling bits as the state of the channel is better, to thus obtain the optimal performance and guarantee the minimum delay time.

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.

A technique for streaming digital video content to a client involves providing a new stream of digital video content to the client using forward error correction (FEC) for a limited initial period and then ending the use of FEC after the limited initial period has ended. In an embodiment, during the limited initial period, the digital video content is provided to the client at a rate that is slightly higher than the playout rate in order to allow a client buffer to accumulate digital video content. FEC continues to be used until the client buffer is sufficiently populated such that lost or damaged frames can be retransmitted to the client before the corresponding digital video content is needed for playout. Once the client buffer is sufficiently populated, FEC is ended and retransmission is used to maintain the quality of the streamed digital video content.

A data field of transmitted digital television signals includes a first set of A / 53-compliant data segments that convey payload information and further includes a second set of A / 53-compliant data segments that contain parity bytes for transverse Reed-Solomon forward-error-correction coding of the data contained within the first set of A / 53-compliant data segments. A digital television receiver uses the parity bytes in the second set of A / 53-compliant data segments to implement transverse Reed-Solomon forward-error-correction decoding that corrects byte errors in the data contained in the first set of A / 53-compliant data segments.

A method and apparatus for optimizing the data transfer rate over a transport layer (i.e., communication link) such as the Internet is provided. Initially the data is prepared for transmission by a transfer rate controller, then the data is encoded by a Forward Error Correction (FEC) encoder. After the data has been transferred over the transport layer, the quality of the data transfer link is assessed by an FEC decoder that determines if any errors occurred during data transfer and if errors are detected, the magnitude of the errors (i.e., FEC-correctable packets, FEC-uncorrectable packets). This information is used to generate a feedback message which is used by the transfer rate controller to adjust and optimize the data transfer rate for the link quality as determined at that point in time. By continually monitoring and assessing link quality and providing feedback to the transfer rate controller, the transfer rate can be continually adapted to the varying link quality. In addition to generating feedback used by the transfer rate controller to optimize data transfer rate, the FEC decoder can generate feedback that is used by the FEC encoder to optimize the FEC algorithm. If desired, feedback from the FEC decoders within the link layer demodulator and / or feedback from the receiver can be used to augment the feedback generated by the FEC decoder.

Transmitters, receivers, and coding schemes to increase data rate and decrease bit error rate of an optical data link are disclosed. Data is transmitted across the link with a less than nominal bit error rate (BER), by encoding the data using a forward error correction (FEC) code or by requesting retransmission of transmitted packets in error. Data is transmitted at a speed that introduces errors at a rate that is in excess of the nominal BER but that may be corrected using the FEC code or retransmission so that the data may be received with less than the nominal BER. The data rate is increased as the link operating speed is increased beyond the overhead required by the FEC codes or retransmission. High speed FEC encoders and decoders facilitating such transmission are disclosed.

An encoding apparatus and a method of encoding a source block including different types of data payloads are provided. The method includes dividing the source block into a predetermined number M of sub blocks, generating a predetermined number P1 of base parity payloads that correspond to each of the predetermined number M of sub blocks by performing first Forward Error Correction (FEC) encoding on each of the predetermined number M of sub blocks, generating a predetermined number P2 of extended parity payloads that correspond to the source block by performing second FEC encoding on a particular type of data payloads among data payloads that make up the source block, and configuring a source coded block based on a predetermined number N of sub coded blocks including the predetermined number M of sub blocks and the predetermined number P1 of base parity payloads generated.

There are described apparatus and methods for adaptive forward error correction (FEC), one use being for video streaming over a wireless network. The apparatus includes an FEC encoder and an adaptive FEC device. The FEC encoder is for encoding k packets of source data into n packets, where n>k, and the n packets include redundant packets. The adaptive FEC device is for adaptively determining a number of the redundant packets to transmit with the encoded k packets, based upon receiving one or more feedback messages. The one or more feedback messages indicate a condition of the wireless network over which the encoded video is to be transmitted.

To increase the robustness of a broadcast DTV signal, complete (207, 187) Reed-Solomon forward-error-correction codewords are coded using binary linear block codes that reduce code rate by two or slightly less, enabling a DTV receiver to correct bit errors. Also, a DTV receiver can use a (15, 8), (16, 8) or (8, 4) block code to locate erroneous bytes for decoding (207, 187) Reed-Solomon code, so twice as many erroneous bytes can be corrected in a 187-byte data packet. The reduced code rate permits robust transmission of a 187-byte data packet in only two data segments and its super-robust transmission using a restricted symbol alphabet in only four data segments. This simplifies time-division multiplexing of data segments used for ordinary 8VSB transmissions with those used for robust and super-robust transmissions. Procedures to make legacy DTV receivers disregard data segments used for robust and super-robust transmission are disclosed.

In a data decoder for decoding data from received symbols received over a channel from an encoder, wherein the received data can include erasures and include source symbols and repair symbols and wherein the decoder uses in decoding a generator matrix, any square submatrix of which is invertible, such that the decoder can perform decoding operations concurrently with the arrival of the source symbols and repair symbols, a method of decoding comprising representing in decoder memory a system of equations derived, at least in part, from the generator matrix, substituting received source symbols into the system of equations as the source symbols are received before receiving all source symbols, identifying, using decoder logic, repair equations to be used for solving the system of equations as repair symbols arrive, calculating, using decoder logic, vector values for equations as source symbols arrive, and converting the system of equations into an upper triangular form as repair symbols arrive at the decoder. Novel methods can be used for interleaving and specifying encoding structure for a large class of FEC codes, scheduling the sending of packets and the like.

In a packet communications system stream data is transported over a channel over which packet loss or corruption is possible, with forward error correction (“FEC”) information. A transmitter receives source packets comprising source data, generates FEC source packets formatted to allow for identification of lost or corrupted source packets at a receiver, arranges source data from the source packets into a plurality of source symbols wherein at least one source packet is arranged into more than one source symbol, associates a plurality of source symbols with a source block, generates a plurality of repair symbols from the source block according to a predetermined FEC encoding process and groups the plurality of repair symbols into one or more FEC repair packets associated with the source block. A receiver can use the FEC repair symbols from the FEC repair packets to recover source symbols, as needed.

The present invention relates to a method and an arrangement for communicating packet information in a digital telecommunications system. Through the invention is selected a set of designated communication resources (ch1-chn) from an available amount of resources. Every packet (P) is forward error correction encoded into an encoded packet (Pci), via one of at least two different coding schemes (ci), prior to being transmitted to a receiving party, over the designated communication resources (ch1-chn). An estimated transmission time is calculated for all combinations of coding scheme (ci) and relevant distribution (dj) of the encoded data blocks (B1-BΓ), in the encoded packet (Pci) over the set of designated communication resources (ch1-chn), and the combination (ci,dj) is selected, which minimises the estimated transmission time.

An apparatus, system, and method are disclosed for providing error correction for a data storage device. A determination module determines a set of error-correcting code (“ECC”) characteristics for a data storage device. The set of ECC characteristics includes at least one attribute selected from a plurality of supported attributes. A decoder configuration module configures an ECC decoder to operate in compliance with the set of ECC characteristics. An ECC module validates requested data read from the data storage device using the ECC decoder.

A computationally simple yet powerful forward error correction code scheme for transmission of real-time media signals, such as digitized voice, video or audio, in a packet switched network, such as the Internet. For each window of k data packets, the invention generates and transmits at least one cross-wise parity packet taken as an index-shifted function over the k data packets. The invention thereby enables a receiving end to recover from packet loss.

An advanced multiplexer designed and optimized for next generation on-demand video distribution is described. Features and capabilities include auto-discovery, channel-staggering and compatibility with static Virtual Channel Tables (VCTs). The multiplexer system facilitates auto-discovery by inserting identifiers into MPTSs (Multi-Program Transport Streams). These identifiers are echoed back to the multiplexer by the client set-top thereby indicating correspondence between modulators, service groups, and clients. When modulating multiple channels, FEC frames (Forward Error Correction frames) are staggered across channels to reduce correlation and clipping in the IFFT processor.

A method and apparatus are described for protecting real time media including receiving media packets, generating media bit strings from the media packets, applying a forward error correcting code across the generated media bit strings to generate at least one forward error correcting bit string and generating at least one forward error correcting packet from the at least one forward error correcting bit string. Also described are a method and apparatus for recovering from losses of real time media packets including forming media bit strings from received media packets, forming forward error correcting bit strings from received forward error correcting packets, decoding the formed media bit strings and forward error correcting bit strings to obtain recovered media bit strings and recover lost media packets from the recovered media bit strings. Further described is a data structure for a forward error correcting header on computer readable media.

A method to meet the adequate QoS of wireless network by automatically sizing the packet length and / or by adding appropriate FEC (Forward Error Correction) based on the error rate forecast that is derived from the past behavior of the wireless communication channel.

A CDM satellite transmission system is disclosed that broadcasts programming content, such as audio and video information, using one or more geo-synchronous satellites based on Code Division Multiple Access technology. Forward error correction coding and interleaving are used prior to broadcasting the signals over the CDM channel to account for signal loss due to short-term fading. The CDM satellite transmission system provides a tuning channel corresponding to each program channel that reduces the delay when a mobile receiver is first tuned to a selected program channel. The tuning channel utilizes a shorter interleaver length, if any, than the corresponding primary program channel. The CDM satellite transmission system transmits a delayed version of a program signal with the on-time version of the audio output to accommodate uninterrupted reception in the event of such a blockage. In one implementation of the invention, the core layer, C(n), of the delayed version of the audio output of a scalable audio coding scheme is utilized as the tuning channel. The core layer, C1(n), and enhancement layers, E1(n), of the on-time signal and the enhancement layers, E2(n), of the delayed-time signal employ a representative block interleaver having a duration of four seconds. The tuning channel (C2(n), of the delayed-time signal) employs a representative block interleaver having a duration of 500 milliseconds.

A quick paging channel in a random access wireless communication system includes at least one bit in a quick paging frame identifying the presence of a paging message for an access terminal or group of access terminals. The quick paging bits identifying the presence of a paging message for a first access terminal is encoded with one or more quick paging bits corresponding to one or more additional access terminals to produce one or more forward error correction bits. The jointly encoded quick paging bits are broadcast to the access terminals by time division multiplexing the quick paging frame with additional frames of information.

A test signal generator at a transmitter station and a facsimile generator at a receiver station go through an acquisition and tracking process which aligns the two signals so that a logical processor can compute the frequency transfer function of the entire propagation path for use in an adaptive, concurrently sent communication signal. The frequency transfer function is conveyed back to the transmit end via a control channel permitting an adaptivity function at the transmit end to influence subsequent selection of communication parameters, among which are typically transmitted data rate, selection of modulation, selection of forward error correcting coding, and selection of frequency band for transmission. The same measurement is conveyed to an adaptivity function at the receive end for use in the communications receiver to select demodulator variables such as gain control, and equalization of amplitude and phase, versus frequency. The adaptivity function also permits interspersing of reverse-direction communications over the same frequency bands in a time-share mode between forward-direction and reverse-direction communication with the measurement signals having to be transmitted in only one direction. An alternate embodiment invention of this type is described which is additionally useful for mobile communications channels. Another variation embodiment is described for pure propagation measurements only, absent conveyance of end-user information.

A method for correcting a short text message comprising the steps of: creating a table of common words and misspellings; identifying keypad used for sending the message, examining message for comprehensibility; identifying most likely error, substituting symbols based on a hierarchical system of shared keys followed by adjacent keys to hypothesize correction of the most likely error; examining hypothesized correction for comprehensibility, and repeating steps (c) to (f) until an understandable message is generated.

A terrestrial digital video broadcasting (DVB-T) network is used to transmit IP datagrams to receiving devices using multiprotocol encapsulation (MPE). MPE datagram section and, if forward error correction (FEC) is used, MPE-FEC datagram sections may include time-slicing parameters, such as a “delta-t” parameter for specifying a time until the next burst is transmitted and a flag for indicating the end of a burst. Thus, MPE and MPE-FEC datagram sections can be transmitted in bursts. Other types of sections, however, do not include such time-slicing parameters and thus cannot usually be transmitted in bursts. Nevertheless, by assembling a burst including at least one MPE or MPE-FEC datagram section which specifies delta-t and MPE or MPE-FEC datagram section at the end of a burst which indicates its position, other types of sections can benefit from being transmitted in bursts.

Data is streamed from a transmitter to a receiver, wherein streaming is transferring data with an assumption that the receiver will begin using the data before it is all transmitted and received and the streamed data includes forward error correction (“FEC”) and the rates of data consumption can vary. The transmitter has an input rate and a transmit rate and the two rates can be different and can change. At the receiver, there is a reception rate (at which the receiver receives data) and a consumption rate (at which the receiver uses up data for its output). The transmitter transmits using a transmit rate higher than the consumption rate and the extra bandwidth is usable for FEC protection and buffering. In some embodiments, the excess rate varies over a transmission period.