Patent ID: 6219374
Filing Date: 2001-04-17
Classification: H04B,H04L

Abstract:
A coherent dual-channel Quadrature Phase Shift Keying (QPSK) transceiver device using pilot symbols in a code division multiple access system, comprising:a serial-to-parallel converter for dividing a communication signal which comprises data bits into an in-phase channel signal and a quadrature channel signal;a first pilot symbol adder for periodically inserting pilot symbols into said in-phase channel signal;a second pilot symbol adder for periodically inserting said pilot symbols into said quadrature channel signals;first and second mixers for spreading said in-phase channel signals and said quadrature channel signals into which said pilot symbols are periodically inserted using different Walsh codes;third and fourth mixers for spreading said in-phase channel signals and said quadrature channel signals which have been spread by said different Walsh codes using different PN codes;first and second pulse-shaping filters for pulse-shaping outputs of said third and fourth mixers, respectively;fifth and sixth mixers for frequency-modulating said pulse-shaped in-phase channel signals and quadrature channel signals into carriers cos(2.pi.f.sub.0 t+.theta..sub.k) and sin(2.pi.f.sub.0 t+.theta.k), respectively; anda high-power amplifier for amplifying outputs of said fifth and sixth mixers and transmitting resulting transmit signals to an antenna.