e functions that we never discover or use, which supports the view that the most profitable user is the user who pays £25 a month and never uses the phone. If the user pays £8.00 a month to insure the phone and never leaves the house that is even better. It is, however, reasonable to state that the functionality of device-centric software and the application value realisable from that software is intrinsically determined by the hardware form factor of the device that in turn determines uplink and downlink offered traffic value and delivery cost. Consider a power-optimised multitasking multithreaded media processor in a mobile broad- band device. An example is shown in Figure 7.1. The core has to be capable of handling multiple inputs and outputs that may combine text, voice, audio (including high-quality audio), image, video and data. For conversational variable bit rate traffic (a small but significant percentage of the future traffic mix), the processor has Device-Centric Software Multiple Inputs Handset Mac Layer and Network Radio Layer Voice Audio Image Video Multi-Tasking Multiple Per Multiple Per User Rate User Rate Multi-Threaded Matched OVSF Matched Processors Mirtual Paths on Code Streams Virtual Circuits Multiple Outputs Voice Audio Image Video Symmetric Asynchronous Traffic Fixed Delay and No Delay Variability For Conversational VBR Services (Voice and Video) Figure 7.1 Multithreaded processor functional block diagram. to maintain the time interdependency between the input and output data streams. In effect, the processor must act as a real-time operating system in the way that it handles multiple media streams into, across and out of the processor core. The same level of determinism then needs to be applied to the MAC and physical radio layer, preserving the time interdependency of the multiple per user rate matched OVSF code streams and then on into the network with multiple per user rate matched virtual paths and circuits. Note that together, the handset media processor, MAC layer and radio layer an