| 摘要 |
In a Discrete Fourier Transform-Spread Orthogonal Frequency Division Multiplex (DFT-SOFDM) transmitter for Evolved-UMTS Terrestrial Radio Access (E-UTRA) signals, each of two cascaded phase rotators 203 and 205 multiply an incoming complex Binary Phase Shift Keyed (BPSK) symbol by some complex value in accordance with different phase rotation constraints in order to prevent transmitters aligning in the In phase/Quadrature (IQ) domain. For example, 203 could output a pi/2 BPSK modulated signal by multiplying by a j, 1, j, 1, ... sequence, which 205 then multiplied by a j, j, j, 1, 1, 1, -1, -1, -1 ... scrambling code, reducing alignment interference and the required amplifier back-off. The symbols are then converted to groups (101) and directly coupled to an M-point DFT (105), without being mapped to constellation as in prior art (103), before entering an N>M-point inverse DFT (107) to retrieve a time domain signal. |
