Field Test Results of SFN Relay with Coupling Loop Interference Canceller at the Himeji Relay Station

Abstract

When building SFN (Single Frequency Network) by broadcast-wave relay in digital terrestrial broadcasting, a part of transmitted signal from a transmitting antenna returns to a receiving antenna and, as a result, coupling loop interference occurs. The coupling loop interference causes relay signal quality degradation and an oscillation. We developed a canceller that suppresses coupling loop interference, and we conducted a field test using the canceller at Himeji relay station that is in the environment where many coupling waves exist and some of them delay long. In the field test, we confirmed that the canceller has stable suppression performance even if desired wave power (D) is less than undesired wave power (U). And the degradation of required C/N for BER (Bit Error Rate) of 7×10^<-3> was less than 1dB at D/U=0dB.