Zero-guard OFDM performance in SFN with ATSC 3.0 ultra-robust transmission modes

Single Frequency Network (SFN) deployments are widely extended in DTT (Digital Terrestrial Television) to deliver the same signal across multiple transmitters. A large-enough guard interval (GI), or cyclic prefix (CP), is required to extend coverage area without SFN self-interference at the expense of increasing capacity overheads. The new DTT standard ATSC 3.0 offers unprecedented features and flexibility for ultra-robust transmissions with Carrier-to-Noise ratios (CNRs) well-below 0 dB. Such robust modes may cope with degradation caused by SFN self-interference, what could enable the suppression of the GI and a corresponding efficiency increase. This paper studies the performance of ultra-robust transmission modes of ATSC 3.0 without GI in SFNs. A set of these modes are compared in SFN scenarios, characterized by different path delays. The impact of the GI duration, scattered pilot (SP) patterns and associated pilot boosting (PB), as well as channel estimation algorithms are analyzed. The results show the potential of Zero-Guard OFDM operation with very low rates (e.g. QPSK 2/15, 3/15) compared to CP-OFDM, where the benefits in performance do not compensate the overhead penalties.