Methods, apparatus, and systems for reducing Peak Average Power Ratio (PAPR) in signal transmissions are described. In one example aspect, a wireless communication method includes determining, for an input sequence of coefficients, an output sequence and generating a waveform using the output sequence. The output sequence corresponds to an output of a convolutional modulation between a three-coefficient function associated with

[00001]$\frac{\sqrt{2}}{2},$

1, and

[00002]$\frac{\sqrt{2}}{2}$

and an intermediate sequence. The intermediate sequence is generated by inserting zero coefficients between coefficients of the input sequence of coefficients

A communication system comprises a transmitter and a receiver that communicate differential phase modulated data over a wireline channel pair. The transmitter encodes data symbols by generating first and second data signals with differentially phase shifted signal transitions with respect to one another. The receiver receives the first data signal and the second data signal and samples the first data signal based on a signal transition timing of the second data signal to generate a first output data symbol. The receiver furthermore samples the second data signal based on signal transition timing of the first data signal to generate a second output data symbol.

An FEC coder in a transmission device according to an exemplary embodiment of the present disclosure performs BCH coding and LDPC coding based on whether a code length of the LDPC coding is a 16k mode or a 64k mode. A mapper performs mapping in an I-Q coordinate to perform conversion into an FEC block, and outputs pieces of mapping data (cells). The mapper defines different non-uniform mapping patterns with respect to different code lengths even an identical coding rate is used by the FEC coder. This configuration improves a shaping gain for different error correction code lengths in a transmission technology in which modulation of the non-uniform mapping pattern is used.

Embodiments of the present disclosure relate to a method and system for transmitting a sequence with low peak-to-average-power-ratio (PAPR). A communication system receives control data. A transmitter of the communication system comprises a plurality of sequences which are associated with the control data in the transmitter. The transmitter selects a sequence from the plurality of sequence. The selected sequence is rotated, pre-coded for generating pre-coded sequence. DFT is applied on the pre-coded sequence for generating frequency domain signals. The frequency domain signals are processed and corresponding waveform is transmitted to a receiver of the communication system. The receiver receives the waveform and is processed to extract the sequence from the waveform. The receiver correlates the extracted sequence with plurality of sequences stored in receiver memory to detect the control data. The generated waveform has low PAPR.

An encoding circuit includes an allocator to allocate a symbol to bit-strings within a first frame, a converter to convert values of target-bit-strings that exclude a predetermined-bit-string so that, as a region within the constellation is closer to a center of the constellation, a number of symbols allocated in the region is larger, a generator to generate an error-correction-code of the bit-strings, and an insertion circuit to delay the error-correction-code and insert the error-correction-code in the predetermined-bit-string within a second frame that succeeds the first frame, wherein the allocator allocates, to the bit-strings, one symbol that corresponds to the values of the target-bit-strings, the one symbol being within a quadrant that corresponds to a value of the predetermined bit-string, and wherein the converter switches, based on the value of the predetermined-bit-string, association relationships between the values of the target-bit-strings before and after the conversion.

Preventing RF signal distortion and signal error producing memory events in a Radio Frequency (RF) power amplifier (RFPA). An element, disposed prior to the Radio Frequency (RF) power amplifier (RFPA) in a signal path of a RF signal input to the RFPA, may enforce a maximum allowable amplitude in a high PAPR instantaneous high peak of the RF signal. An element may also increase or supplement a bias of the Radio Frequency (RF) power amplifier (RFPA) when a high PAPR instantaneous high peak is detected in the RF signal prior to receipt by the RFPA. Additionally, a first element operable detects when an instantaneous output voltage of the Radio Frequency (RF) power amplifier (RFPA) is below a predetermined voltage, and in response, a second element supplies additional current to prevent the output voltage of the RFPA from falling below a predetermined threshold voltage.