Transmitter using symbol constellation rotation and spectrum shaping, transmission method thereof, receiver and reception method thereof in communication system

A discrete Fourier transform (DFT)-spread orthogonal frequency division multiplexing (OFDM) transmission method performed by a DFT-spread OFDM transmitter, the DFT-spread OFDM transmission method comprising:

• constellation-rotating a symbol vector b comprising M pulse amplitude modulation (PAM) symbols by a constellation rotation angle ϕ to generate a constellation-rotated symbol vector d;
• spreading the constellation-rotated symbol vector d by using a pruned DFT matrix WL,M to generate a pruned DFT-spread vector c;
• performing a Hadamard product on the pruned DFT-spread vector c with a shaping vector s to generate a frequency domain spectrum shaped vector a;
• and
• allocating the frequency domain spectrum shaped vector a to a subcarrier in an allocated frequency range.

A discrete Fourier transform (DFT)-spread orthogonal frequency division multiplexing (OFDM) receiver comprising:

• a cyclic prefix (CP) removal unit receiving a signal y passing through a channel, and removing a CP from the signal y to generate a CP-removed vector {tilde over (y)};
• an N-point DFT unit performing N-point DFT on the CP-removed vector {tilde over (y)} and cutting out a part corresponding to a subcarrier in an allocated frequency range to generate a vector ã;
• a frequency domain reception spectrum shaping unit performing a Hadamard product on the vector ã resulting from cutout of the part corresponding to the subcarrier in the allocated frequency range with a conjugate complex vector of a reception shaping vector sR to generate a frequency domain reception spectrum shaped vector;
• a pruned IDFT unit multiplying the frequency domain reception spectrum shaped vector by a prefixed pruned DFT matrix WL,MH to generate a despread vector;
• an inverse constellation rotation unit inversely constellation-rotating the despread vector by an inverse constellation rotation angle −ϕ to generate an inversely constellation-rotated vector;
• and
• an estimation unit taking a real number part of the inversely constellation-rotated vector to generate an estimated value of a transmitted pulse amplitude modulation (PAM) symbol vector.

A discrete Fourier transform (DFT)-spread orthogonal frequency division multiplexing (OFDM) reception method performed by a DFT-spread OFDM receiver, the DFT-spread OFDM reception method comprising:

• receiving a signal y passing through a channel, and removing a cyclic prefix (CP) from the signal y to generate a CP-removed vector {tilde over (y)};
• performing N-point DFT on the CP-removed vector {tilde over (y)} and cutting out a part corresponding to a subcarrier in an allocated frequency range to generate a vector ã;
• performing a Hadamard product on the vector ã resulting from cutout of the part corresponding to the subcarrier in the allocated frequency range with a conjugate complex vector of a reception shaping vector sR to generate a frequency domain reception spectrum shaped vector;
• multiplying the frequency domain reception spectrum shaped vector by a prefixed pruned DFT matrix WL,MH to generate a despread vector;
• inversely constellation-rotating the despread vector by an inverse constellation rotation angle −ϕ to generate an inversely constellation-rotated vector;
• and
• taking a real number part of the inversely constellation-rotated vector to generate an estimated value of a transmitted pulse amplitude modulation (PAM) symbol vector.