had similar problems to overcome. ISDBT, specified originally for the Japanese market, is arguably the most scalable of the present digital broadcast OFDM systems. It divides a 6-MHz channel into subchannel segments each of just over 400 kHz each segment has a variable OFDM multiplex, variable modulation (QPSK, 16 QAM, 64 QAM) and variable levels of convolutional coding. Table 15.3 summarises these capabilities. Although the system promises substantial deployment flexibility, performance (as with DVB H) will be dependent on achieving successful (RF) integration into existing and future cellular transceivers and global scale. Updated adoption status by country can be found on the ISDBT web site. 13 Media FLO was Qualcomm's proprietary offering for broadcast receivers. It shared some common techniques with DVB H in that it used a time division multiplex, with one or more traffic packets being transmitted within a reserved slot to all users in the service area. Users received the same packets from multiple cells. An OFDM multiplex was used to slow down the symbol rate and the symbols were soft combined to improve downlink performance. Media FLO was deployed into Channel 55 in the UHF band. It had the merit of being intrin- sically compatible with existing and future 1X EV DO networks but no inherent compatibility to the US TV ATSC system. The deployment of Media FLO prompted ATSC to develop a mobile optimised ATSC implementation. The market failure of Media FLO and subsequent 13 http://www.dibeg.org/. Terrestrial Broadcast/Cellular Network Integration Table 15.3 ISDBT Mode 1 Mode 2 Mode 3 Number of segments One or three Bandwidth 432.5 kHz (one 430.5 kHz (one 429.5 kHz (one segment) 1.289 MHz segment) 1.287 MHz segment) 1.286 (three segments) (three segments) MHz (three segments) Carrier spacing 3.968 kHz 1.984 kHz 0.992 kHz Number of carriers 109 (one segment) 325 217 (one segment) 433 (one (three segments) 649 (three segments) segment) 1297 (three segments) Modulation QPSK, 16QAM, 64 QAM, DQPSK Number of symbols p