ONE-SEG TECHNOLOGIES FOREMERGENCY BROADCAST BASED ONDIGITAL TERRESTRIAL TELEVISION BROADCASTING

摘要

Digital Terrestrial Television Broadcasting servicesrnusing the ISDB-T system[1],[2] were started in December,rn2003 in Japan. A mobile, handheld TV service based onrnISDB-T, the so-called "One-Seg" service, has beenrnpopular since it started in April 2006. The cumulativernshipment of One-Seg receivers exceeded 41 million inrnAugust 2008. We have developed two technologies forrnsending emergency broadcast to One-Seg receivers.rnOne is for the Emergency Warning Broadcastingrn(EWB) system, a significant component of ISDB-T. Itrnenables a signal to be sent that activates One-Segrnreceivers automatically if a disaster such as a tsunamirnoccurs so that information broadcast to alert the generalrnpublic is received and displayed.rnThe other is for the Earthquake Early Warningrn(EEW) system, which started to be broadcast inrnOctober 2007. An EEW is issued by the JapanrnMeteorological Agency as soon as an earthquake isrndetected, even before ground movement occurs. NHKrnbroadcasts the EEW by superimposing it on TV andrnradio programs. However, there has been no way tornknow of an EEW broadcast without having a TV orrnradio turned on, even with ISDB-T, including One-Seg.rnThe technology we developed for this system enables arnsignal to be sent that activates One-Seg receiversrnautomatically so that they display an alert promptlyrnafter an EEW is issued.