| 摘要 |
<p>PURPOSE: To extend the number of multiplexed users considerably even under high speed fading environment in a direct spread CDMA system. CONSTITUTION: An M-value digital modulator 102 modulates m(m is an integer 2 or over) bits of binary digital signal into M (M=2<m> ) value symbol prior to spread operation by multipliers 103, 104 in a transmitter. In a receiver, after inverse spread processing by an M filter 207, an M value digital demodulator 208 compensates fluctuation in carrier phase and amplitude for the M value modulation signal. A discrimination device 209 discriminates symbols of an output of an M value digital demodulator. A tap coefficient control means 214 calculates orthogonal coefficients by using outputs of subtractors 212, 213, outputs of the M value digital demodulator, reception filters 205, 206 and a spread code. The output symbol of the discrimination device 209 is converted into an m-bit signal and then the m-bits are synthesized into one series.</p> |
