and acceptable RF performance in practical handset designs. 4.4.1 Differentiating RF Technology and RF Engineering Costs Technology costs are the recurring costs in the device and a composite of the component technologies needed to support the chosen air interface, or interfaces in single-mode, dual- mode and multimode devices. SAW filters for example are one of the enabling technologies used in the RF section of a modern cellular handset. They have a defined function (to achieve selectivity) and an associated cost that may or may not decrease over time and over volume. Telecommunications Economies of Scale Engineering costs are more typically (though not always) nonrecurring in that they are a composite of the engineering time and effort needed to achieve a certain desired result using a mix of available technologies. Nonrecurring engineering costs have to be amortised over a certain production volume within a certain time. Cost implies risk and risk implies a business need to achieve a certain return on investment (ROI). Thus, the price charged for components and for the engineering effort needed to turn those components into finished product will directly reflect the return on investment criteria. This return on investment criteria is not static and may change over time. More significantly, the return on investment will be determined by the number of vendors competing to supply components and finished product to a defined market. If a market is too small in terms of either volume or value then the likely outcome is that the market will be undersupplied both in terms of the number of component vendors and the amount of engineering effort needed to turn those components into cost and performance competitive product. This will inflate realised prices, limit choice and compromise operator time to market. Additionally, the handsets that are available will probably perform poorly in terms of their RF functionality. This in turn will limit achievable user data rates (capacity) and the data/voice geographic footprint 