501 results about "Convolutional code" patented technology

Apparatus and methods store error recovery data in different dimensions of a memory array. For example, in one dimension, block error correction codes (ECC) are used, and in another dimension, supplemental error correction codes, such as convolutional codes, are used. By using separate dimensions, the likelihood that a defect affects both error recovery techniques is lessened, thereby increasing the probability that error recovery can be performed successfully. In one example, block error correction codes are used for data stored along rows, and this data is stored in one level of multiple-level cells of the array. Supplemental error correction codes are used for data stored along columns, such as along the cells of a string, and the supplemental error correction codes are stored in a different level than the error correction codes.

The present invention relates to methods, apparatuses, and systems for performing data encoding involving encoding data bits according to an outer convolutional code to produce outer encoded bits processing the outer encoded bits using an interleaver and a logical unit to produce intermediate bits, wherein the logical unit receives a first number of input bits and produces a second number of corresponding output bits, the second number being less than the first number, and wherein the logical unit takes each of the first number of input bits into account in producing the second number of output bits, encoding the intermediate bits according to an inner convolutional code to produce inner encoded bits, wherein the inner convolutional code is characterized by at least two states, and combining the data bits and the inner encoded bits to produce encoded outputs.

The transmission of ATM, Internet, and satellite communications is unified through international standardized protocol embedment. Global and Local performance optimization are achieved through the combination of combinatorial, dynamic, and probabilistic programming. A simultaneous domino effect of bandwidth conservation, efficiency enhancement, reliability improvement, traffic congestion prevention, delay minimization, and speed multiplication are realized for any digital communication system, particular in Internet. With three levels of error coding in ATM cells, the loss cell recovery and bit integrity are preserved. From its mathematical roots, new combinatorial sets are systematically generated, and applications of the sets are identified. Among the applications, optimal sequences can be produced for multi-user and multi-function communication system designs. Optimality is in terms of maximum possible number of sequences with given sequence length and sequence characteristics. The results are unique and theoretically proven. By serial and parallel concatenation of error codecs, reliability of multimedia transmission can be satisfied to any desirable level. As a part of the unified transmission scheme, the acquisition and synchronization method of cascading sequences exhibits significant improvement in correlation properties and detection probabilities. A method of using block designs is demonstrated to derive, to generate, and to construct low-density parity check block codes and threshold decodable convolutional codes. An efficiency evaluation method is formulated for the combination operation of ATM, Internet, and satellites.

PCT No. PCT/FR97/00607 Sec. 371 Date Apr. 19, 1999 Sec. 102(e) Date Apr. 19, 1999 PCT Filed Apr. 3, 1997 PCT Pub. No. WO97/38495 PCT Pub. Date Oct. 16, 1997Disclosed are a method and a device for the convolutive encoding of blocks each formed by a predetermined number N of source data elements, wherein each of said source data elements is introduced twice into one and the same convolutive encoder implementing a generating polynomial with a period L in an order such that the two instances of introduction of one and same source data element di are separated by the introduction of (pi.L)-1 other source data elements, pi being a non-zero integer. Also disclosed are a corresponding decoding method and device that can be applied, in particular, to the transmission of short messages, for example in radiotelephony, for satellite communications or gain computer telecommunications (Internet for example). FIG. 2.

Apparatus and methods store data in a non-volatile solid state memory device according to a rate-compatible code, such as a rate-compatible convolutional code (RPCC). An example of such a memory device is a flash memory device. Data can initially be block encoded for error correction and detection. The block-coded data can be further convolutionally encoded. Convolutional-coded data can be punctured and stored in the memory device. The puncturing decreases the amount of memory used to store the data. Depending on conditions, the amount of puncturing can vary from no puncturing to a relatively high amount of puncturing to vary the amount of additional error correction provided and memory used. The punctured data can be decoded when data is to be read from the memory device.

In iterative-diversity (ID) transmission systems for signals with concatenated convolutional coding (CCC), paired iterative diversity signals each have ½ the code rate of the 8VSB DTV signals prescribed by the 1995 ATSC Digital Television Broadcast Standard. Known serial concatenated convolutional coding (SCCC) or novel parallel concatenated convolutional coding (PCCC) is used in such system. Pairs of CCC signals code data bits and ones' complemented data bits respectively, using similar coding algorithms. Receivers for this transmission system use respective turbo decoders for turbo decoding the earlier-transmitted and later-transmitted CCC signals. Turbo decoding of the earlier-transmitted portions of iterative diversity signals is delayed to be contemporaneous with turbo decoding of the later-transmitted portions of iterative diversity signals. This facilitates the turbo decoders exchanging information concerning confidence levels of data bits during the turbo decoding procedures.

Decoding signals represented by a trellis of block length N divided into windows of length L includes a step of decoding a forward recursion from a point P that is before the beginning of a window up to the beginning of the window. P is chosen at a sufficient distance from the beginning of the window such that forward recursion determines a known state metric at the beginning of the window. A next step includes decoding the window using forward recursion from the known state at the beginning of the window up to the end of the window to define a set of known forward recursion state metrics which are stored. A next step includes decoding using backward recursion starting from a known state at the end of the window and moving backward. A next step includes calculating a soft output at each stage of the backward recursion using the stored forward recursion state metrics, and branch metrics at each stage, and outputting the soft output for that stage in a LIFO format.

Decoder for low-density parity check convolutional codes. In at least some embodiments, a decoder (200) for arbitrary length blocks of low-density, parity-check codes includes a plurality of interconnected processors (202), which further include a plurality of interconnected nodes. A memory can be interconnected with the nodes to store intermediate log likelihood ratio (LLR) values based on channel LLR values. Thus, LLR values having successively improved accuracy relative to the channel LLR values can be output from each processor, and eventually used to decision information bits. In some embodiments, the memory is a random access memory (RAM) device that is adapted to store the intermediate LLR values in a circular buffer. Additionally, a storage device such as a read-only memory (ROM) device can be used to generate a predetermined plurality of addresses for reading and writing LLR values.

A low-density parity check convolution code (LDPC-CC) is made, and a signal sequence is sent after subjected to an error-correcting encodement using the low-density parity check convolution code. In this case, a low-density parity check code of a time-variant period (3g) is created by linear operations of first to 3g-th (letter g designates a positive integer) parity check polynomials and input data.

A pseudo-chaotic coding/modulation method. The coding method exploits symbolic dynamics of a chaotic map at the transmitter to encode data. The encoding synthesizes the chaotic map based upon the data to be transmitted. In a preferred embodiment, pseudo-chaotic iterates are generated from a digital implementation of a Bernoulli shift map. The output of the shift map is translated by a mapping, preferably implemented by a digital signal processor, to allow transitions between states in a transmitted signal to differ, and the translated map is used to drive a modulator (for example PPM, FSK, PSK, QAM, etc.). In the specific case of pulse-position modulation (PPM) the translated map is used to modulate pulse train positions within a periodic synchronization frame. The preferred embodiment uses a shift register to implement an approximation of the Bernoulli shift map acting as a form of convolutional code with a number of states equal to the symbolic states defined on the chaotic map. A receiver may use fewer states and still decode the data signal, allowing receiver scalability.

The present invention relates to a multicarrier direct sequence code division multiple access (DS/CDMA) system using a turbo code with nonuniform repetition coding. In particular, it relates to a multicarrier DS/CDMA system using a turbo code with unequal diversity order in its code symbols instead of using a convolutional code.

A combined decoder reuses input/output RAM of a turbo-code decoding circuit as alpha-RAM or beta-RAM for a convolutional code decoding circuit. Additional operational units are used for both turbo-coding and convolutional coding. An effective harware folding scheme permits calculation of 256 states serially on 8 ACS units.

A reception apparatus for OFDM signals having a short initial rise time since start of reception until outputting the sound and/or a picture. An OFDM reception apparatus 1 of the ISDB-T standard presets the TMCC information at the outset in a memory 19 in association with each broadcasting station. This TMCC information contains the information on the RF frequency and the guard interval length, time interleaving pattern information, the information on the carrier modulation scheme and the information on the code rate of the convolutional code. When a user selects a broadcasting station, a control circuit 18 reads out the TMCC information associated with the broadcasting station from the memory 19. The control circuit 18 affords the read-out TMCC information to each circuit to set e.g., the guard interval or the carrier modulation scheme.

A transmitting system, a receiving system, a method of processing broadcast signals and a method of receiving broadcast signals are disclosed.

The method for transmitting a broadcast signal in a transmitter includes encoding mobile data for forward error correction (FEC) to build Reed-Solomon (RS) frames and dividing the built RS frames into RS frame portions, dividing the RS frame portions into Serially Concatenated Convolutional Code (SCCC) blocks and mapping the SCCC blocks to data blocks and scalable data blocks, corresponding to a plurality of data segments, wherein at least one of the SCCC blocks includes one of the data blocks and one of the scalable data blocks, encoding signaling data including a header and a payload, forming data groups including the data blocks and the scalable data blocks, wherein specific data blocks of the data blocks in the data groups include the signaling data having information for a number of ensembles being a collection of services transmitted through the data groups, interleaving data in the data groups, wherein the interleaved data includes a plurality of data segments, and wherein at least one of the plurality of data segments includes a part of one of the data blocks and a part of one of the scalable data blocks and transmitting the interleaved data during slots in a transmission frame.

In the decoding method in a convolutional code system of a Reed-Solomon code concatenation and feedback system, the concatenated code is composed of an external code and an inner code. For this code structure, at least one big iterative decoding is performed in the decoding method; and in each big iterative decoding, the inner code is decoded first, then the decoding code of each external code decoder is obtained after the software output of the inner decoder is passed through a deinterleaver and a software information processor. The invention uses simplified criterion to select the output code of RS code, thereby reduces the number of error pattern of chase-2 algorithm; The RS code decoder not only provides prior probability information of a information sequence to RSC code decoder, but also modifies the symbol of the information sequence at the same time, thereby increases the effectiveness of information transfer between the inner decoder and the external decoder.

A transmitting system, a receiving system, and a method of processing broadcast signals are disclosed. The method for transmitting a broadcast signal includes encoding mobile data for forward error correction (FEC) to build Reed-Solomon (RS) frames, dividing the built RS frames into a number of RS frame portions, dividing one of the RS frame portions into Serially Concatenated Convolutional Code (SCCC) blocks, mapping the SCCC blocks including the convolution-coded data to mobile data blocks according to a SCCC block mode which identifies relationship between the mobile data blocks and the SCCC blocks, forming a data group including the mobile data blocks, forming mobile data packets including data in the data group and, multiplexing a specified number of the mobile data packets, a first scalable number of the mobile data packets, and a second scalable number of main data packets.

The present invention provides a versatile system for selectively spreading carrier data across multiple carrier paths within an Orthogonal Frequency Division Multiplexing (OFDM) system (200), particularly an ultra-wideband (UWB) system. The present invention provides a data input (202), which passes data to a randomizer (204). The data then passes to a convolutional code function (206), the output of which is punctured by puncturing function (208). An interleaver function (210) receives the punctured code data, and cooperatively operates with a mapper element (218) to prepare the coded data for pre-transmission conversion by an IFFT (220). The mapper element (218) comprises a dual carrier modulation function (216), which associates and transforms two punctured code data elements into a format for transmission on two separate signal tones.

Decoding signals represented by a trellis of block length N divided into windows of length L includes a step of decoding a forward recursion from a point P1 that is before the beginning of a window up to the beginning of the window and decoding a backward recursion from a point P2 that is after the end of a window back to the end of the window to define known states at the beginning and end of the window. A next step includes decoding the window using backward recursion from the known state at the end of the window back to the beginning of the window to define a set of backward recursion state metrics. A next step includes decoding using forward recursion starting from a known state at the beginning of the window and moving forward to the end of the window to define a set of forward recursion state metrics. A next step includes calculating a soft output at each stage of the window using the forward and backward recursion state metrics, and branch metrics at each stage, and outputting the soft output for that stage.

The invention discloses an iterative decoding method of an RS product code concatenated convolutional code system, which comprises the following steps of: step S001: providing a convolutional code decoder and an RS product code decoder, and then soft-decision decoding the convolutional code decoder; de-interleaving the bit level soft information transmitted by the convolutional code decoder, and then decoding by the RS product code decoder; and interleaving the bit level external information generated by the RS product code decoder and feeding back to a BCJR decoder as a priori probability; step S002: checking the code word of the RS product code, when the stop condition can not be satisfied after checking, the number of iterations is added with 1, implementing the step S003, and when the stop condition can be satisfied after checking, implementing the step S004; and the decoding method can fully utilize the soft information.