New Pulse Shapes for Partial Response Signaling to Outperform Faster-than-Nyquist Signaling

Faster-than-Nyquist (FTN) signaling is the promising idea that theoretically provides a significant increase in the spectral efficiency without energy loss. The gain is achieved through incorporating intersymbol interference (ISI) by simply increasing symbol rate. Another way to increase spectral efficiency is to use pulses assuming incorporating ISI. It is commonly called Partial Response (PR) signaling. Both approaches face certain difficulties in the signal processing as the conventional processing chain including a matched filter causes colored noise. Also, FTN signaling and PR signaling achieve declared gains only asymptotically, i.e. at very low values of the bit error rate (BER) and a high computational complexity of the detection algorithms. In this paper, we propose two methods of signal processing with ISI. Both of them cause white noise. The former is suitable for simulation and the latter is suitable for practical implementation. Additionally, we propose a new optimization criterion for synthesizing pulses for PR signaling. It is shown in the article that PR signaling with the pulses proposed by us outperform FTN signaling and PR signaling with other known optimal pulses. Moreover, it is achieve the Mazo limit at BER = 10
⁻⁴
and with low computational complexity of signal detection.