A receiver apparatus for receiving an OFDM radio signal comprising a first plurality of subcarrier-symbols, modulated on a corresponding plurality of subcarriers, and a second plurality of subcarrier-symbols, modulated on the corresponding plurality of subcarriers, to generate first and second bit sequences, the first bit sequence being an interleaved version of the second bit sequence according to a predetermined interleave function. Soft-output decoder logic generates a first soft-bit sequence for the first plurality of subcarrier-symbols, and a second soft-bit sequence for the second plurality of subcarrier-symbols. Combiner logic combines the soft-bit sequences, with the soft-bit sequences either both in an interleaved state or both in a non-interleaved state, by combining a respective soft-bit having a bit position in the first soft-bit sequence with a respective soft-bit having a same bit position in the second soft-bit sequence. Hard-output decoder logic outputs a hard-bit sequence representing the transmitted bit sequence.

An apparatus and method for broadcast signal frame using a bootstrap including a symbol for signaling a BICM mode and OFDM parameters of a preamble, together are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a time interleaver configured to generate a time-interleaved signal by performing interleaving on a BICM output signal; and a frame builder configured to generate a broadcast signal frame including a bootstrap and a preamble using the time-interleaved signal. In this case, the bootstrap includes a symbol for signaling a BICM mode and OFDM parameters of L1-Basic of the preamble, together.

Disclosed herein are a method for transmitting and receiving compressed data and an apparatus therefor. According to the method for transmitting compressed data, a transmission apparatus for transmitting compressed data standardizes the value of an In-phase/Quadrature-phase (IQ) data sample to a preset type that is selected from among a positive number and a negative number, determines the sample type of the IQ data sample, the value of which is standardized to the preset type, based on a sample type determination rule, generates a compressed bit string based on the compression rule pertaining to the determined sample type, generates compressed data, including at least one of a reference bit corresponding to the sample type, the sign bit of the IQ data sample, and the compressed bit string, for each IQ data sample, and transmits the compressed data to a reception apparatus.

A channel estimation technique suitable for implementation at a digital communication receiver such as an optical signal receiver apparatus includes receiving, over a communication channel, a transmission comprising a sequence of modulated symbols, estimating, at multiple frequencies, estimated values of a channel transfer function of the communication channel and selectively revising the estimated values of channel transfer function by reducing glitches in the estimated values of the channel transfer function.

Disclosed herein are a method for transmitting and receiving compressed data and an apparatus therefor. According to the method for transmitting compressed data, a transmission apparatus for transmitting compressed data standardizes the value of an In-phase/Quadrature-phase (IQ) data sample to a preset type that is selected from among a positive number and a negative number, determines the sample type of the IQ data sample, the value of which is standardized to the preset type, based on a sample type determination rule, generates a compressed bit string based on the compression rule pertaining to the determined sample type, generates compressed data, including at least one of a reference bit corresponding to the sample type, the sign bit of the IQ data sample, and the compressed bit string, for each IQ data sample, and transmits the compressed data to a reception apparatus.

This invention relates to methods and systems for estimating skew based on, for example, the IEEE 1588 Precision Time Protocol (PTP). These methods and systems can allow the clock skew between a master clock (server) and slave clock (client) exchanging PTP messages over a packet network to be estimated more rapidly than conventional estimation techniques and thereby improve the convergence of standard estimation algorithms. In one embodiment, the skew estimation is derived from a set of timestamps from a message exchange between the master and slave using a non-linear least square-fitting algorithm. An example of the fitting algorithm is the Levenberg-Marquardt algorithm.

An apparatus and method for broadcast signal frame using a bootstrap including a symbol for signaling a BICM mode and OFDM parameters of a preamble, together are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a time interleaver configured to generate a time-interleaved signal by performing interleaving on a BICM output signal; and a frame builder configured to generate a broadcast signal frame including a bootstrap and a preamble using the time-interleaved signal. In this case, the bootstrap includes a symbol for signaling a BICM mode and OFDM parameters of L1-Basic of the preamble, together.

An apparatus and method for broadcast signal frame using a bootstrap including a symbol for signaling a BICM mode and OFDM parameters of a preamble, together are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a time interleaver configured to generate a time-interleaved signal by performing interleaving on a BICM output signal; and a frame builder configured to generate a broadcast signal frame including a bootstrap and a preamble using the time-interleaved signal. In this case, the bootstrap includes a symbol for signaling a BICM mode and OFDM parameters of L1-Basic of the preamble, together.

Systems for utilizing bandwidth of a wireless network in an efficient manner are disclosed. Bandwidth may be allocated between different types of devices by dividing a symbol constellation into subsets of points, where each of the subsets may be used for transmitting data from a different device to a base station on single frequency channel. The symbol constellation may be shared on the frequency channel by dynamic or static allocation of the subsets of points to different devices. A first device with high data speed requirements may be allocated a first subset of points of the symbol constellation fix transmitting data to the receiver, while a second device with lower data speed requirements may be allocated a second smaller subset of the symbol constellation for transmitting data to a receiver. The first and second devices may then transmit data to the receiver on the frequency channel.

The present disclosure teaches methods for digitally transmitting data. An example method may include: receiving a modulated signal containing at least one useful signal or noise or interference signals; repeatedly estimating at least one parameter of the received signal relevant to the demodulation of the useful signal; monitoring changes in the repeatedly estimated parameters; and detecting a useful signal based at least in part on whether one or more changes in the repeatedly estimated parameters satisfy at least one particular, predefined condition.