Study on hierarchical transmission toward the advanced ISDBT development : xe2x80x93 Comparison of FDM with LDM xe2x80x93 In Japan, the next generation of the Integrated Services Digital BroadcastingTerrestrial (ISDBT) system is being developed to transmit largevolume content services such as ultrahigh definition television (UHDTV). Since 2016, we have been researching and developing transmission systems for terrestrial broadcasting as part of the research program xe2x80x9cResearch and Development for advanced Digital Terrestrial Television Broadcasting Systemxe2x80x9d, under the auspices of the Ministry of Internal Affairs and Communications, Japan. The transmission system studied in this program is called xe2x80x9cadvanced ISDBTxe2x80x9d. The transmission performance of the advanced ISDBT is better than that of ISDBT. The advanced ISDBT has been considered to adopt frequency division multiplexing (FDM) for the baseline of hierarchical transmission to transmit mobile services and fixed services in one channel. However, layered division multiplexing (LDM), which can improve spectrum efficiency, has been also studied. In this paper, we compare FDM with LDM, adopt a new signal structure, modulation, and forward error collection (FEC) studied in the development of the advanced ISDBT. Finally, we clarify how multiplexing technology could affect both mobile and fixedlayer transmission.

Mobile Performance of Next Generation Japanese Terrestrial Broadcasting Research into the possibility of a next generation Japanese terrestrial broadcasting system is underway in Japan. As part of that effort, a system based on frequency division multiplexing (FDM) as used in ISDBT has been created. Multiple layers can be transmitted at the same time using different frequency divisions known as segments, such as a mobile layer and a layer for fixed reception. In this paper we report on simulations of performance of the mobile layer of this system using typical reception algorithms in a TU6 channel. We show that while a different sampling frequency has been adopted for the possible next generation system, and even with the choice of 16384 FFT, mobile reception under highway conditions can be obtained while increasing the data rate significantly.