A method includes for a designated pilot symbol of at least one pilot symbol to be inserted into a data sequence, determining a first subcarrier and a second subcarrier adjacent to a position of the designated pilot symbol in a frequency domain; at least separately determining a first position and a second position on the first subcarrier and the second subcarrier; determining a first symbol and a second symbol, so that the first symbol is capable of neutralizing interference on the designated pilot symbol of data symbols in positions other than the first position within a predetermined range of the first subcarrier, and the second symbol is capable of neutralizing interference on the designated pilot symbol of data symbols in positions other than the second position within a predetermined range of the second subcarrier; and respectively inserting the first symbol and the second symbol in the first and second positions.

A system and method are provided for processing symbols for transmission. The method involves producing a single carrier offset quadrature amplitude modulation (OQAM) waveform signal from a set of K complex symbols. The method further involves pulse shaping 2K frequency domain samples of the OQAM waveform signal with J non-zero coefficients, where the J non-zero coefficients represent a frequency response of a conjugate symmetrical pulse shape, and K≤J≤2K−1. The approach has the advantage of avoiding self-interference, with the result that better BLER performance may be possible. The approach is applicable to any modulation order and also avoids bandwidth expansion. Flexibility is provided through a trade-off between PAPR vs. spectrum efficiency.

A system and method are provided for processing symbols for transmission. A set of 2K outputs is produced that includes K real components and K imaginary components from K complex symbols. A Fourier transform operation on the 2K outputs produces 2K Fourier transform outputs. Transmit pulse shaping is applied to the 2K Fourier transform outputs. The transmit pulse shape may be Nyquist or non-Nyquist. An inverse Fourier transform operation on the J pulse shaped outputs produces an inverse Fourier transform output. In the receiver, equalization is performed to remove the effect of both the channel and the transmit pulse shape. Nyquist pulse shaping is performed by applying a Nyquist pulse shape prior to converting back to time domain. The approach avoids self-interference, even in situations where the transmit pulse shape is non-Nyquist. The transmitter is free to select a pulse shape to optimize PAPR without being concerned with interference.

An OFDM transmitter and an OFDM receiver respectively transmit and receive N (N≥2, N is an integer) control symbols. For each control symbol, a guard interval time-domain signal is, for example, identical to a signal obtained by frequency-shifting at least a portion of a useful symbol time-domain signal by an amount different from any other symbol, or to a signal obtained by frequency-shifting one or both of a portion and a span of a useful symbol interval time-domain signal different from any other symbol by a predetermined amount.

Embodiments of the present disclosure describe an underwater optical communication and illumination system employing laser diodes directly encoded with data, including spectrally efficient orthogonal frequency division multiplex quadrature amplitude modulation (QAM-OFDM) data. A broadband light source may be utilized to provide both illumination to an underwater field of interest and underwater optical communication from the field of interest to a remote location.

A system and method are provided for processing symbols for transmission. A set of 2K outputs is produced that includes K real components and K imaginary components from K complex symbols. A Fourier transform operation on the 2K outputs produces 2K Fourier transform outputs. Transmit pulse shaping is applied to the 2K Fourier transform outputs. The transmit pulse shape may be Nyquist or non-Nyquist. An inverse Fourier transform operation on the J pulse shaped outputs produces an inverse Fourier transform output. In the receiver, equalization is performed to remove the effect of both the channel and the transmit pulse shape. Nyquist pulse shaping is performed by applying a Nyquist pulse shape prior to converting back to time domain. The approach avoids self-interference, even in situations where the transmit pulse shape is non-Nyquist. The transmitter is free to select a pulse shape to optimize PAPR without being concerned with interference.

The disclosed systems, structures, and methods are directed to a wireless receiver. The configurations presented herein employ a signal encoder configured to encode a plurality of received analog signals into a single encoded analog composite signal, in accordance with a variable leading bit orthogonal coding scheme, an analog-to-digital converter (ADC) configured to convert the single encoded analog composite signal into a single encoded digital composite signal containing constituent digital signals, a synchronization module configured to provide the variable leading bit orthogonal coding scheme to the signal encoder, and a signal decoder configured to decode the single encoded digital composite signal in accordance with the variable leading bit orthogonal coding scheme, to output a plurality of digital signals containing the desired information content of the received plurality of analog signals.

An OFDM transmitter and an OFDM receiver respectively transmit and receive N (N2, N is an integer) control symbols. For each control symbol, a guard interval time-domain signal is, for example, identical to a signal obtained by frequency-shifting at least a portion of a useful symbol time-domain signal by an amount different from any other symbol, or to a signal obtained by frequency-shifting one or both of a portion and a span of a useful symbol interval time-domain signal different from any other symbol by a predetermined amount.

A system and method are provided for processing symbols for transmission. The method involves producing a set of 2K outputs that include K real components and K imaginary components from K complex symbols, performing a Fourier transform operation on the 2K outputs to produce 2K Fourier transform outputs, pulse shaping the 2K Fourier transform outputs by multiplying each of J of the 2K Fourier transform outputs with a respective one of J non-zero coefficients, where J is odd, and KJ2K1, performing an inverse Fourier transform operation on the J pulse shaped outputs to produce an inverse Fourier transform output; and outputting the inverse Fourier transform output. The approach has the advantage of avoiding self-interference, with the result that better BLER performance may be possible. The approach is applicable to any modulation order without bandwidth expansion. Flexibility is provided through a trade-off between PAPR vs. spectrum efficiency.

A system and method are provided for processing symbols for transmission. The method involves producing a set of 2K outputs that include K real components and K imaginary components from K complex symbols, performing a Fourier transform operation on the 2K outputs to produce 2K Fourier transform outputs, pulse shaping the 2K Fourier transform outputs by multiplying each of J of the 2K Fourier transform outputs with a respective one of J non-zero coefficients, where J is odd, and KJ2K1, performing an inverse Fourier transform operation on the J pulse shaped outputs to produce an inverse Fourier transform output; and outputting the inverse Fourier transform output. The approach has the advantage of avoiding self-interference, with the result that better BLER performance may be possible. The approach is applicable to any modulation order without bandwidth expansion. Flexibility is provided through a trade-off between PAPR vs. spectrum efficiency.