Simulation of communication systems using personal computers

Using a precoding technique to reduce the BER penalty of an M-QAM channel in hybrid AM-VSB/M-QAM subcarrier multiplexed lightwave systems

“…Therefore, given one of the 6000 random phase combinations of the 42 AM channels, we used up to 500 symbols to estimate the resultant 64-QAM BER [8], i.e., each point on a BER curve is the average result of 6000 x 500 symbols. If additional distortions such as carrier phase error and symbol timing error were to be included, much more than 500 symbols must be used for each combination [8] [9]. In addition, when the 42-channel phases are coherent enough to induce clipping, the dominant time interval between clipping events is 4…”

Using precoding technique to reduce the BER penalty of an M-QAM channel in hybrid AM-VSB/M-QAM subcarrier multiplexed lightwave systems

“…If additional distortions such as carrier phase error and symbol timing error were to be included, much more than 500 symbols must be used for each combination [8], [9]. In addition, when the 42-channel phases are coherent enough to induce clipping, the dominant time interval between clipping events is 4 s [6], and therefore, 200 symbols with 0.2 s 200 40 s duration can include about 10 dominant clipping intervals.…”