Single Frequency Network Broadcasting with 5GNR Numerology

This paper investigates the possibility of using 5G New Radio (5GNR) OFDM numerology in the deployment of efficient Single Frequency Networks (SFNs) for delivering TV services to user devices. The straightforward approach in the design of the physical layer for broadcasting application is based on the adoption of OFDM signalling with very long OFDM symbol and very low sub-carrier spacing (SCS). This design choice allows to dimension the Cyclic Prefix length to eliminate ISI and ICI induced by the large delay spread with a consequent overhead reduction. The 5GNR numerology is designed for unicast transmission and Cyclic Prefix lengths are not compatible with those required for large SFN networks. In this paper we consider a general receiver based on the channel shortening principle, but in the frequency domain. The receiver consists in a bank of per tone time/frequency 2D filters, possibly followed by Maximum-Likelihood (ML) trellis processing on the shortened channel. We provide promising information theoretic bound showing that the extension of 5GNR numerology to SFN is possible with very small performance loss. Even the simplest detector architecture that does not employ trellis processing provides throughput competitive with those that can be obtained with smaller SCS. We provide end to end simulation results with practical modulation and LDPC encoder confirming that the results predicted by the bounds can be closely matched in practice.