 need to work equally effectively at 850 MHz, 900 and 1800 MHz, 1700/2100 MHz, at 800 and 1700 MHz in Japan, at 700 MHz at 800 MHz and at 2.6 GHz. 3 http://www.rttonline.com/documents/rfcosteconhsetss.pdf. Making Telecoms Work However, as we shall see in Chapter 5, there is a significant risk that LTE devices and parallel HSPA + Release 8, 9, 10 and 11 devices will not follow this positive improvement curve and may well exhibit a far wider best to worst spread than UMTS or GSM. This should be of major concern to all operators or analysts with responsibility for assessing mobile broadband access economics. As with GSM and UMTS, the addition of each incremental LTE band implies substantial nonrecurring engineering expenditure and small but significant additional component costs in terms of diplex and duplex filter functions. Adding nonstandard bands over and above these presently allocated bands will be problematic in terms of engineering resource allocation (not enough engineers available to do the required design and optimisation work). As we shall see, this explains why vendors work on high 'opportunity cost' multipliers when asked to produce handsets for nonstandard bands and/or nonstandard technologies. Additionally, as we have stated, each additional band introduces additional performance loss. It is quite possible that this incremental performance loss will be more significant for LTE devices than for UMTS or GSM devices. 4.5 The RF Functions in a Phone RF functions in a cellular phone include the selective RF front end, the receiver low-noise am- plifier (LNA), RF to IF mixing, the frequency synthesiser and the transmitter power amplifier (PA). The function of the front end is to capture signals of interest on the receive path and to propagate a signal on the transmit path. The receiver LNA amplifies the signal of interest on the receive path. The mixing process takes the incoming signal and mixes it with a second frequency to create an intermediate frequency (IF) at which the signal will be processed. In d