Fig. 5

BER vs received power for the DS and US signals in single-channel operation. Insets: received a 10.7 Gb/s BPSK, b 10.7 Gb/s Alamouti-coded OFDM QPSK, and c 21.4 Gb/s Alamouti-coded OFDM 16-QAM constellations around the HD-FEC threshold, assumed to be 4 × 10⁻³. AC-OFDM: Alamouti-coded OFDM