Japan's first cable TV was introduced at the Ikaho hot spring in Gunma Prefecture in 1955, two years after TV broadcasting began, as community antenna television system to solve the issue of poor TV reception. With the introduction of multichannel support, cable TV now provides independent broadcast programs in addition to retransmission (now called "rebroadcasting", meaning community reception) of TV programs.
 For cable TV, a bandwidth of 90 - 770 MHz is divided into 6-MHz channels. Each channel transmits digital signals by using 64-QAM (Quadrature Amplitude Modulation: a digital modulation scheme to sequentially transmit any of 64 different symbols by using amplitude and phase) or 256-QAM. The transmission capacity of each channel is about 29 - 38 Mbit.
 Even with the latest video compression technologies, it is difficult to transmit 8K SHV over cable TV network with a single channel. So, we have developed a method to transmit 8K SHV over multiple cable channels. About 100 Mbit/s of signals (the capacity expected to be transmitted by one satellite transponder) can be transmitted with a combined use of three cable TV channels.
 This method has three characteristics. First, channels of different transmission capacity can be combined for use. Next, unused capacity of each existing channel can be bundled for use and the current service can be received with the conventional receiver.Third, to replay video and other data on a PC or tablet, it needs to be distributed in a file type. The 8K SHV cable transmission method can transmit IP packets that can store files. As these packets are of variable length, it is possible to partition data to packets of the same fixed length as a conventional TS packet (188 bytes) for transmission.
【 The method to transmit SHV signals over multiple channels 】

 Information and Communications Council of the Ministry of Internal Affairs and Communications issued specifications of this transmission method as "Technical requirements for implementing ultra-high-definition TV broadcasting on cable TV".
 To realize and universally spread an appealing 8K SHV broadcasting, we will continue our R&D and standardization of technologies to deliver the service not only on satellite broadcasting but on cable TV.
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