US 12,348,349 B2
Spectrum shaping method for generating signal having almost constant envelope in communication system, and transmitter performing same
Joon Ho Cho, Gyeongsangbuk-do (KR); and Jeong Hoon Choi, Gyeongsangbuk-do (KR)
Assigned to Samsung Electronics Co., Ltd., (KR)
Appl. No. 18/557,417
Filed by Samsung Electronics Co., Ltd., Gyeonggi-do (KR)
PCT Filed Sep. 1, 2021, PCT No. PCT/KR2021/011769
§ 371(c)(1), (2) Date Oct. 26, 2023,
PCT Pub. No. WO2022/239912, PCT Pub. Date Nov. 17, 2022.
Claims priority of application No. 10-2021-0062248 (KR), filed on May 13, 2021.
Prior Publication US 2024/0214254 A1, Jun. 27, 2024
Int. Cl. H04L 27/26 (2006.01)
CPC H04L 27/2636 (2013.01) 6 Claims
OG exemplary drawing
 
1. A discrete Fourier transform (DFT)-spread orthogonal frequency division multiplexing (OFDM) transmitter comprising:
a phase shifter configured to generate a pi/2-binary phase shift keying (BPSK) symbol vector d by phase-shifting a vector b including M BPSK symbols;
a DFT spreader configured to generate a DFT-spread pi/2-BPSK symbol vector x by spreading the pi/2-BPSK symbol vector d by using an M-point DFT matrix WM;
a circular extender configured to generate a circularly extended pi/2-BPSK symbol vector y by periodically extending the DFT-spread pi/2-BPSK symbol vector x,
a frequency domain spectrum shaper configured to generate a frequency domain spectrum shaped pi/2-BPSK symbol vector z by multiplying each element of the circularly extended pi/2-BPSK symbol vector y by each element of a first shaping vector sT;
a subcarrier allocator configured to allocate the frequency domain spectrum shaped pi/2-BPSK symbol vector z to subcarriers in an allocated frequency range; and
an inverse DFT (IDFT) unit and a cyclic prefix (CP) adder configured to generate a DFT-spread OFDM transmission signal by performing an IDFT and inserting a CP to the pi/2-BPSK symbol vector z allocated to the subcarriers,
wherein the frequency domain spectrum shaped pi/2-BPSK symbol vector z is obtained by performing a Hadamard product of the circularly extended pi/2-BPSK symbol vector y and the first shaping vector sT,
wherein the first shaping vector sT is determined according to the M and a number L of the subcarriers to be used,
wherein an l-th element of the first shaping vector sT is determined to be a value obtained by equidistant sampling of continuous-time Fourier transform of a minimum shift keying (MSK) waveform defined by the following equation:

OG Complex Work Unit Math
and
wherein the value is a sampled value at a certain location defined by the following equation

OG Complex Work Unit Math
where l=1, 2, . . . , L.