Mobile reception performance of ISDB-TSB mobile multimedia broadcasting system using the VHF-low band

摘要

After analog television broadcasting was terminated in Japan, the frequency bands from 90 to 108 MHz (VHF-low band) and from 207.5 to 222 MHz (VHF-high band) were reallocated to mobile multimedia broadcasting (MMB). We propose three methods to improve the mobile reception performance with VHF-low MMB. These involve the extended time-interleaving length, space diversity reception technology, and iterative decoding technology between Viterbi decoding and Reed-Solomon decoding. This paper describes improvements of the mobile reception performance evaluated through laboratory and field experiments. As a result of laboratory experiments, the extension of time-interleaving length from I=4 (0.5 s) to I=32 (4 s) improved the mobile reception performance by 2.7 dB, three-fold iterative decoding improved it by 1 dB, and 2-branch space diversity reception improved it by 6.4 dB at a vehicle speed of around 30 km/h. Combining the three methods improved it by 8.9 dB. We conducted field experiments, and the results from these matched those from the laboratory experiments.