During the BPSE process, a high-speed special mode frame is sent, bit error rate (BER) is fed back to the sender, as well as signal to noise (SNR) and BERs for each rate are obtained by looking up the empirical BER/SNR curve.

• 其中，BPSE先通过发送高速特征序列串来测量比特误码率(Bit ErrorRate)，然后根据BER/SNR(Signal to Noise Ratio)经验曲线，查表得出当前信道的SNR以及当前SNR下各个速率的BER。