Burst mode interference cancellation for superposed transmission of SSMA-QPSK signals and TDMA-QPSK signals in nonlinear channels

This paper proposes a burst mode interference cancellation scheme for SSMA (Spread Spectrum Multiple Access)-QPSK (Quadrature Phase Shift Keying) signals superposed over TDMA (Time Division Multiple Access)-QPSK signals. The newly proposed burst mode interference cancellation scheme cancels only the interference due to DATA part of the TDMA burst. Experimental results show that the proposed cancellation scheme coupled with the coding-rate of one-half FEC (Forward Error Correction) increases the Eb/No degradation by only 0.1 dB over the continuous mode interference cancellation scheme when the ratio of the preamble length (CR,BTR and UW) to the burst length equals 0.014. Therefore, the proposed cancellation scheme transmits twenty SSMA-QPSK channels simultaneously over a nonlinearly amplified TDMA-QPSK signals as well as the continuous mode interference cancellation scheme does.