A cluster receives a request to store an object using replication or erasure coding. The cluster writes the object using erasure coding. A manifest is written that includes an indication of erasure coding and a unique identifier for each segment. The cluster returns a unique identifier of the manifest. The cluster receives a request from a client that includes a unique identifier. The cluster determines whether the object has been stored using replication or erasure coding. If using erasure coding, the method reads a manifest. The method identifies segments within the cluster using unique segment identifiers of the manifest. Using these unique segment identifiers, the method reconstructs the object. A persistent storage area of another disk is scanned to find a unique identifier of a failed disk. If using erasure coding, a missing segment previously stored on the disk is identified. The method locates other segments. Missing segments are regenerated.

A cluster receives a request to store an object using replication or erasure coding. The cluster writes the object using erasure coding. A manifest is written that includes an indication of erasure coding and a unique identifier for each segment. The cluster returns a unique identifier of the manifest. The cluster receives a request from a client that includes a unique identifier. The cluster determines whether the object has been stored using replication or erasure coding. If using erasure coding, the method reads a manifest. The method identifies segments within the cluster using unique segment identifiers of the manifest. Using these unique segment identifiers, the method reconstructs the object. A persistent storage area of another disk is scanned to find a unique identifier of a failed disk. If using erasure coding, a missing segment previously stored on the disk is identified. The method locates other segments. Missing segments are regenerated.

Technologies for applying a redundancy encoding scheme to segmented portions of a data block include an endpoint computing device communicatively coupled to a destination computing device. The endpoint computing device is configured to divide a block of data into a plurality of data segments as a function of a transmit window size and a redundancy encoding scheme, and generate redundant data usable to reconstruct each of the plurality of data segments. The endpoint computing device is additionally configured to format a series of network packets that each includes a data segment of the plurality of data segments and generated redundant data for at least one other data segment of the plurality of data segments. Further, the endpoint computing device is configured to transport each of the series of network packets to a destination computing device. Other embodiments are described herein.

A coding and modulation apparatus and method are presented. The apparatus comprises an encoder that encodes input data into cell words, and a modulator that modulates said cell words into constellation values of a non-uniform constellation. The modulator is configured to use, based on the total number M of constellation points of the constellation and the signal-to-noise ratio SNR in dB, a non-uniform constellation from a group of constellations comprising one or more of predetermined constellations defined by the constellation position vector w.sub.0 . . . b−1, wherein b=M/4.

A coding and modulation apparatus and method are presented. The apparatus comprises an encoder that encodes input data into cell words, and a modulator that modulates said cell words into constellation values of a non-uniform constellation. The modulator is configured to use, based on the total number M of constellation points of the constellation and the signal-to-noise ratio SNR in dB, a non-uniform constellation from a group of constellations comprising one or more of predetermined constellations defined by the constellation position vector w.sub.0 . . . b−1, wherein b=M/4.

A code bit of an LDPC code in which a code length is 16200 bits and an encoding rate is 8/15 is interchanged with a symbol bit of a symbol corresponding to any of 8 signal points defined by 8PSK. When 3 bits of code bits stored in three units of storages having a storage capacity of 16200/3 bits and read bit by bit from the units of storages are allocated to one symbol, a (#i+1)-th bit from a most significant bit of the 3 bits of code bits is set to a bit b#i, a (#i+1)-th bit from a most significant bit of 3 bits of symbol bits of the one symbol is set to a bit y#i, and a bit b0 is interchanged with a bit y1, a bit b1 is interchanged with a bit y0, and a bit b2 is interchanged with a bit y2.

The present invention is directed to communication systems and methods. In a specific embodiment, the present invention provides a receiver that includes an error correction module. A syndrome value, calculated based on received signals, may be used to enable the error correction module. The error correction module includes an error generator, a Nyquist error estimator, and a decoder. The decoder uses error estimation generated by the Nyquist error estimator to correct the decoded data. There are other embodiments as well.

A bit interleaver, a bit-interleaved coded modulation (BICM) device and a bit interleaving method are disclosed herein. The bit interleaver includes a first memory, a processor, and a second memory. The first memory stores a low-density parity check (LDPC) codeword having a length of 64800 and a code rate of 7/15. The processor generates an interleaved codeword by interleaving the LDPC codeword on a bit group basis. The size of the bit group corresponds to a parallel factor of the LDPC codeword. The second memory provides the interleaved codeword to a modulator for quadrature phase shift keying (QPSK) modulation.

A transmitter is provided. The transmitter includes: a Low Density Parity Check (LDPC) encoder configured to encode input bits to generate an LDPC codeword including the input bits and parity bits to be transmitted in a current frame; a parity permutator configured to perform parity-permutation by interleaving the parity bits and group-wise interleaving a plurality of bit groups configuring the interleaved parity bits based on a group-wise interleaving pattern including a first pattern and a second pattern; a puncturer configured to puncture some of the parity-permutated parity bits; and an additional parity generator configured to select at least some of the punctured parity bits to generate additional parity bits to be transmitted in a previous frame of the current frame, based on the first pattern and the second pattern, wherein the first pattern determines parity bits to remain after the puncturing and then to be transmitted in the current frame.

Embodiments of the present invention provide a method and apparatus for tone interleaving wide channel bandwidths or transmissions using multiple-bands. Embodiments of the present invention are designed to accommodate new generations of WLAN. According to some embodiments, existing communication standards of the current generations of WLAN are used to simplify the implementation of the tone mapping schemes described herein. For example, some embodiments of the present invention use an 80 MHz channel bandwidth with resource units having 996 tones as a building block to efficiently implement new tone mapping and interleaving schemes for wider bandwidth channels.