and or to use channel bonding at 5 GHz. This is one of those circular arguments. The WiFi PHY and MAC were never designed to support a significant mix of time-bounded services. It is reasonable to assume that IP voice, and in the longer term IP video and IP voice and video will become a progressively more important part of the offered traffic mix (and by implication a more important part of offered traffic value). This implies that handsets and access points will need to support higher data rates. Higher data rates are achieved by implementing mixed mode 802.11 b and g, which implies additional contention overhead. The connection based nature of voice and voice and video calls also adds contention overhead and signalling bandwidth load. The fact that users might expect to walk around when using WiFi IP voice implies the need to manage mobility, which implies the need to introduce network-assisted handover, which implies the need to implement RSSI or packet error measurements. If you are doing RSSI or packet error measurement you may as well implement per packet power control, which will help to improve capacity and coverage (by lowering the overall noise floor and by improving sensi- tivity in the receiver). This in turn will help reduce some of the power budget issues. The higher data rates are needed partly because time bounded services absorb bandwidth but also because time-bounded services are more expensive to deliver in terms of PHY and MAC utilisation. This all has to make sense to the network operator. Probably the most significant shift here will be the inclusion of network operator-specific browsers in the next generation of SuperSIM smart cards. Rather like existing application layer WiFi browser products, these will identify preferred networks, which of course means preferred networks from a network operator perspective. At this point, WiFi becomes a profit opportunity not a threat. But also the proposition must make sense to the end user and this implies a need for power efficiency. Table 3.18 shows 