152 results about "Identity matrix" patented technology

A low density parity check (LDPC) code that is particularly well adapted for hardware implementation of a belief propagation decoder circuit is disclose& The LDPC code is arranged as a macro matrix (H) whose rows and columns represent block columns and block rows of a corresponding parity check matrix (Hpc). Each non-zero entry corresponds to a permutation matrix, such as a cyclically shifted identity matrix, with the shift corresponding to the position of the permutation matrix entry in the macro matrix. The block columns of the macro matrix are grouped, so that only one column in the macro matrix group contributes to the parity check sum in any given row. The decoder circuitry includes a parity check value estimate memory which may be arranged in banks that can be logically connected in various data widths and depths. A parallel adder generates extrinsic estimates that are applied to parity check update circuitry for generating new parity check value estimates. These parity check value estimates are stored back into the memory, and are forwarded to bit update circuits for updating of probability values for the input nodes. Variations including parallelism, time-sequencing of ultrawide parity check rows, and pairing of circuitry to handle ultrawide code rows, are also disclosed.

The transmit diversity and symbol rate in a wireless mobile system are increased by allocating the complex symbols to be transmitted in accordance with a time-space slot format that incorporates non-orthogonal-based matrices, defined as matrices whose format is such that the product of the matrix and its Hermitian transpose is other than the identity matrix times a real number other than unity. The non-orthogonal-based matrices are indexed by antenna and by symbol period. Copies and complex conjugates (or negative complex conjugates) of the same symbol that are transmitted from different antennas are mutually separated into non-adjacent parts of the slot. Each non-orthogonal-based “space-time” matrix is composed of orthogonal-based matrices, i.e., matrices other than non-orthogonal-based matrices. Preferably, sequences of complex conjugates are time-reversed in the slot.

A low density parity check (LDPC) code generating method and apparatus are provided. A parity check matrix with (N−K) rows for check nodes and N columns for variable nodes are formed to encode an information sequence of length K to a codeword of length N. The parity check matrix is divided into an information part matrix with K columns and a parity part matrix with (N−k) columns. The parity part is divided into P×P subblocks. P is a divisor of (N−K). First and second diagonals are defined in the parity part matrix and the second diagonal is a shift of the first diagonal by f subblocks. Shifted identity matrices are placed on the first and second diagonals and zero matrices are filled elsewhere. An odd number of delta matrices each having only one element of 1 are placed in one subblock column of the parity part matrix. The parity check matrix is stored.

The present invention relates to a decoding method and a decoding apparatus in which, while the circuit scale is suppressed, the operating frequency can be suppressed within a sufficiently feasible range, and control of memory access can be performed easily, and to a program therefor. By using a transformation check matrix obtained by performing one of or both a row permutation and a column permutation on an original check matrix of LDPC (Low Density Parity Check) codes, the LDPC codes are decoded. In this case, by using, as a formation matrix, a P×P unit matrix, a quasi-unit matrix in which one or more 1s, which are elements of the unit matrix, are substituted with 0, a shift matrix in which the unit matrix or the quasi-unit matrix is cyclically shifted, a sum matrix, which is the sum of two or more of the unit matrix, the quasi-unit matrix, and the shift matrix, and a P×P 0-matrix, the transformation check matrix is represented by a combination of a plurality of the formation matrices. A check node calculator 302 simultaneously performs p check node calculations. A variable node calculator 304 simultaneously performs p variable node calculations.