154results about "Error correction/detection using turbo codes" patented technology

An improved turbo code based incremental redundancy includes a first step of puncturing a data stream for a first transmission to provide a set of first unpunctured trellis sections. A next step includes puncturing a data stream for a second transmission to provide a set of second unpunctured trellis sections. A next step includes incremental redundancy combining the first and second transmissions of the trellises to provide non-adjacent first and second unpunctured trellis sections. The above arrangement results in a uniform distribution of punctured and unpunctured bits to provide lower errors.

A communication device is provided with a turbo encoder (1) which carries out a turbo encoding process on the lower two bits of transmission data so as to output information bits of two bits and redundant bits of two bits, a conversion (2) which carries out calculations so as to uniform error-correction capabilities on respective information bits by using the output, decoders (11 to 18) which carries out a soft-judgment on the lower two bits of the received signal that are susceptible to degradation in the characteristics so as to estimate the original transmission data, and a second judging device (19) which carries out a hard-judgment on the other bits in the received signal so as to estimate the original transmission data.

The present invention is particularly applied to serial concatenated coding and serial concatenated trellis coded modulation. In second encoding 107, which is inner coding, a sequence that is not encoded or that is encoded so as to produce a finite impulse response and a sequence that is encoded so as to produce an infinite impulse response are output. In interleaving 106 before the second encoding 107, the sequences are permuted so as not to be mixed with each other.

A method and apparatus for decoding a linear block encoded string of information bits comprising: converting the string into a plurality of codewords. Performing hard and soft decisions on each codeword to generate a hard and soft decision vector. Computing the syndrome and finding the location of the two minimum values by Galois Field Arithmetic. Designating these values LOW1 and LOW2 and xoring with a Nc1, thus generating Nc2. Swapping Nc1 with Nc2 and determining the lowest soft decision value, Min1 and a next lowest value, Min2. The two bit locations creating Min1 are designated as MinA and MinB. MinA being replaced with Min2 minus the value MinA. MinB being replaced with Min2 minus the value at MinB. Generating an output codeword by subtracting Min1 from all other bit locations values and 2's complementing all soft values with 0 in their location. Creating the new soft value vector.

A communication satellite system provides for spectral efficient data transmissions by a gateway to multiple user terminals by way of a satellite. The gateway transmits multiple blocks in a single slot, each block intended for one of the user terminals, where each block is encoded and modulated according to a scheme that may be different for each intended user terminal. Upon re-transmission of a block if that block is lost or received in error, the block may be encoded and modulated according to another scheme that is less spectrally efficient than in the first transmission of the block.

A bandwidth-efficient concatenated trellis-coded modulation (TCM) decoder which is realized by combining turbo codes having an advantage of coping effectively with a fading channel with TCM having an advantage of bandwidth efficiency, and a decoding method thereof are provided. A conventional TCM method has high bandwidth efficiency suitable for transmitting information at high speed. However, it is very sensitive to InterSymbol interference (ISI) so it is usually applied to a wire communication system rather than to a wireless communication system. A turbo code method is an error correction encoding method showing steadiness in a channel having severe ISI and having an excellent error correction ability, but has drawbacks of low data transmission rate and low bandwidth efficiency due to a low code rate. Bandwidth-efficient concatenated TCM is provided for enhancing the steadiness against ISI and-improving power and bandwidth efficiency by applying the turbo code method to a TCM having a code rate of m / (m+1) to compensate for the drawbacks of the conventional TCM and turbo codes. A newly provided decoding method in bandwidth-efficient concatenated TCM uses a SOVA algorithm, thereby reducing decoder complexity and path memory. In addition, bandwidth-efficient concatenated TCM encoder and decoder are provided such to have parallel transition, thereby reducing the complexity of the bandwidth-efficient concatenated TCM decoder. Therefore, the Bandwidth-efficient concatenated TCM is applied to a high speed wireless communication system and can increase bandwidth efficiency and coding gain.

A method and apparatus for decoding a linear block encoded string of information bits comprising: converting the string into a plurality of codewords. Performing hard and soft decisions on each codeword to generate a hard and soft decision vector. Computing the syndrome and finding the location of the two minimum values by Galois Field Arithmetic. Designating these values LOW1 and LOW2 and xoring with a Nc1, thus generating Nc2. Swapping Nc1 with Nc2 and determining the lowest soft decision value, Min1 and a next lowest value, Min2. The two bit locations creating Min1 are designated as MinA and MinB. MinA being replaced with Min2 minus the value MinA. MinB being replaced with Min2 minus the value at MinB. Generating an output codeword by subtracting Min1 from all other bit locations values and 2's complementing all soft values with 0 in their location. Creating the new soft value vector.