A coded VSB-QPSK transmission scheme for digital satellite communications in co-channel interference environments

A coded VSB (vestigial side band)-QPSK (quadrature phase-shift keying) transmission scheme is proposed to realize interference-resistant digital satellite communication system. It uses an interference suppression filter to suppress the interference power in the receiving side. The suppressed power can be assigned to the transmission signals in advance by also using a same characteristic band limitation filter in the transmission side. Moreover, high coding-gain forward error correction (FEC) is employed to improve the degradation due to I and Q channel crosstalk by interference suppression. When a D/U (desired and undesired signal power ratio) equals 3 dB and a /spl Delta/f/f/sub N/ (/spl Delta/f: interference frequency offset, f/sub N/: one-half the Nyquist bandwidth) equals 1.05, the proposed scheme achieves an Eb/No improvement of 7.3 dB in a CCI (co-channel interference) environment.