On information rates for faster than Nyquist signaling

In this paper we consider the information rates of faster than Nyquist (FTN) signaling schemes. We consider binary, quaternary and octal schemes that use root raised cosine pulses. Lower and upper bounds to the information rates are given. The main result is that the lower bounds are often above the information rates for standard Nyquist signaling schemes. This implies that FTN must be superior to Nyquist signaling in some cases. Test results for one coding scheme are given; these show that high throughput communication based on FTN is indeed practical