Decoding a bitset, each bit of the bitset corresponding to a respective value in a range of a minimum value to a maximum value, includes decoding, from a compressed bitstream, indexes of bits of the bitset, each bit of the bits having a first value. Decoding the bitset also includes setting all other bits of the bitset not decoded from the compressed bitstream to a second value. Decoding the indexes of bits of the bitset includes decoding a number of the indexes of the bits of the bitset, decoding a first index of the indexes in a first range having a first lower bound and a first upper bound, and decoding a last index of the indexes in a second range having a second lower bound and a second upper bound.

A communication system SYS includes a transmission apparatus 1 and a reception apparatus 2. The transmission apparatus includes: a conversion unit 111 for converting a bit stream Z having a bit length b into a bit stream Y that has w1 (w is an integer equal to or larger than 2) bit 1 and that has a bit length n (n>b); a conversion unit 112 for converting the bit stream Y into a bit stream X having a bit length t (t<n); and a Neural Network 113 that has a t input node and that outputs a value relating to a feature of a transmission signal Tx when the bit stream X is inputted thereto. The reception apparatus includes: a Neural Network 212 that has a t output node and that outputs a numerical data stream U including t numerical data when a feature of the reception signal is inputted thereto; a conversion unit 213 for converting the numerical data stream U into a numerical data stream Y including n numerical data; and a generation unit 214 for generating a bit stream Z having the bit length b by performing, on the numerical data stream U, an inverse conversion of a conversion processing performed by the conversion unit 111.

Described is a method of image compression and decompression involving a variable-to-variable coding scheme, for example as used or of similar nature to a HT Cleanup encoding algorithm, as described in ISO/IEC 15444-15:2019. The method involves a lookup table that the encoder addresses using a potentially modified version of the EMB pattern, a potentially modified version of the significance pattern, and any additional context information, in order to find the associated variable length codeword. The modified significance pattern and modified EMB pattern, each consisting of 1 bit per sample in a quad, implicitly identify the quad's original significance pattern and the quad's 1-bit unsigned residual offset value, together with some or all of the quad's original EMB pattern, both when the unsigned residual offset value is 1 and, for specific values of the significance pattern, when the unsigned residual offset value is 0.

A computer-implemented method for in-channel function computation in a digital communication system, with a plurality of transmitting digital units and one or more channels, includes the steps of: digitally encoding input data according to one or more transmitting encoding schemes; transmitting digitally encoded input data from the transmitting digital units through the channels; obtaining superpositions of the digitally encoded input data from the plurality of the transmitting digital units in the one or more channels; based on a decoding scheme, which assigns, to any one of the possible superpositions of the transmitted digitally encoded input data, a predefined value corresponding to a predefined combination of the digitally encoded input data, decoding the superpositions of transmitted digitally encoded input data, thereby obtaining combinations of the digitally encoded input data. A digital communication system implementing the method and a receiver implementing the step of decoding of the method are disclosed.

According to one embodiment, a conversion device includes a demultiplexer, first to Nth extractors and a deinterleave unit. The demultiplexer extracts first to Nth substreams from a first compressed stream. The first to Nth substreams are placed in order in the first compressed stream and include first variable-length codes to Nth variable-length codes into which first symbols to Nth symbols of a symbol string have been converted. The first to Nth extractors extract the first variable-length codes to the Nth variable-length codes from the first to Nth substreams. The deinterleave unit reorders the first variable-length codes to the Nth variable-length codes in accordance with the symbol string and outputs a second compressed stream.