Disclosed are techniques related to wireless communication system in which multi-level encoded modulation (MLCM) is applied to non-coherent communication. In the proposed techniques, a small fraction of differential phase rotations or bits participating in differential symbol coding are protected with strong codes while other complementary differential phase rotations or bits are protected with weaker codes. Compared to conventional non-coherent communication techniques in which a uniform protection is applied to any fraction of differential phase rotation or any bit of a differential symbol, the proposed MLCM approach enables more spectrally efficient scheme.

Disclosed are techniques related to wireless communication system in which multi-level encoded modulation (MLCM) is applied to non-coherent communication. In the proposed techniques, a small fraction of differential phase rotations or bits participating in differential symbol coding are protected with strong codes while other complementary differential phase rotations or bits are protected with weaker codes. Compared to conventional non-coherent communication techniques in which a uniform protection is applied to any fraction of differential phase rotation or any bit of a differential symbol, the proposed MLCM approach enables more spectrally efficient scheme.

Upon receipt of a coherent optical signal that includes a training signal generated using a code sequence constituted by multi-value phase modulation symbols, in which a deviation angle of a vector average of a one-symbol delay differential component of a signal generated on the basis of the code sequence has a prescribed angle and a modulation phase difference between adjacent symbols has a fixed, repeated pattern, a reception training signal corresponding to a training code sequence for frequency offset estimation is detected within a reception signal acquired by converting the received coherent optical signal into an electric signal, a plurality of delay differential components are calculated on the basis of the detected reception training signal and at least two delay signals of the reception training signal, each delay signal having a different number of delay symbols, and an averaged frequency offset amount is calculated using the calculated plurality of delay differential components.

A ternary phase shift keying transmitter and receiver can efficiently communicate using ternary encoded data that avoids indistinguishable transition curves for each of the three modulated states in the ternary encoded data. The transmitter is interoperable and can function with different types of receivers including direct detection-based receivers and coherent detection-based receivers.

A ternary phase shift keying transmitter and receiver can efficiently communicate using ternary encoded data that avoids indistinguishable transition curves for each of the three modulated states in the ternary encoded data. The transmitter is interoperable and can function with different types of receivers including direct detection-based receivers and coherent detection-based receivers.

Upon receipt of a coherent optical signal that includes a training signal generated using a code sequence constituted by multi-value phase modulation symbols, in which a deviation angle of a vector average of a one-symbol delay differential component of a signal generated on the basis of the code sequence has a prescribed angle and a modulation phase difference between adjacent symbols has a fixed, repeated pattern, a reception training signal corresponding to a training code sequence for frequency offset estimation is detected within a reception signal acquired by converting the received coherent optical signal into an electric signal, a plurality of delay differential components are calculated on the basis of the detected reception training signal and at least two delay signals of the reception training signal, each delay signal having a different number of delay symbols, and an averaged frequency offset amount is calculated using the calculated plurality of delay differential components.

A ternary phase shift keying transmitter and receiver can efficiently communicate using ternary encoded data that avoids indistinguishable transition curves for each of the three modulated states in the ternary encoded data. The transmitter is interoperable and can function with different types of receivers including direct detection-based receivers and coherent detection-based receivers.

An information transmission method related to the field of communications technologies includes: generating an orthogonal frequency division multiplexing (OFDM) symbol, where the OFDM symbol includes a pi/2-BPSK modulated data signal and a pi/2-binary phase shift keying (BPSK) modulated phase tracking reference signal (PTRS); and sending the OFDM symbol. This method may be applied to an uplink single carrier transmission scenario or a downlink single carrier transmission scenario.

A ternary phase shift keying transmitter and receiver can efficiently communicate using ternary encoded data that avoids indistinguishable transition curves for each of the three modulated states in the ternary encoded data. The transmitter is interoperable and can function with different types of receivers including direct detection-based receivers and coherent detection-based receivers.

A phase adjustment method, a related device, and a system, the method comprising obtaining phases and amplitudes of M symbols adjusting a phase of each of the M symbols to an adjusted phase, wherein the adjusting the phase of each of the M symbols to the adjusted phase includes performing at least one of setting the adjusted phase of the first symbol to the phase of the respective symbol, or setting the adjusted phase of a symbol greater than the first symbol according to the phase of the respective symbol and further according to a sum of phases of all symbols whose amplitudes are greater than an amplitude threshold in a group of one or more symbols from a first symbol to an (i1).sup.th symbol.