10:15 - 11:30 | Wed 6 Jul | Pentland B | R8.2
Microwave backhaul links can nowadays deliver rather impressive throughput, however 5G systems will require further higher efficiencies and a promising solution is the so-called faster than Nyquist (FTN) transmission. A FTN communication is obtained when the Nyquist inter-symbol interference (ISI) criterion is not respected because the transmission rate is higher than that for which the shaping filter is designed. While increasing the achievable rate, the complexity increase has up to now discouraged application of FTN in practical systems. In this paper, we propose to compensate for the ISI by means of a non-linear precoding strategy, i.e. the Tomlinson-Harashima precoder (THP), in turn eliminating the need for costly equalizations at the receiver. We characterize the performance of the proposed FTN system by deriving analytical bounds on the achievable rates of the transmissions over a FTN microwave link using high-order modulations and capacity achieving codes. The proposed solution is capacity-achieving at high SNR (which is the operating regime of backhaul microwave links) and has a complexity that does not increase with the density of the constellation. Numerical results show the effectiveness of the THP-FTN solution paving the way towards its implementations on microwave links.