d network transport have to deliver tightly managed fixed delay and no delay variability, a requirement inconsistent with many existing processor cores. Processor loading is also generally being considered in terms of asymmetric loading - for instance, a higher processor load on the downlink (from network to mobile). This assumption is really not appropriate for conversational variable bit rate services that are and always will be symmetric in terms of their processor load - a balanced, though highly asynchronous, uplink and downlink. Note also that a balanced uplink/downlink implies a higher RF power budget for the handset. Most RF power budgets assume that the handset will be receiving more data than it is transmitting, which is not necessarily the case. A higher RF power budget in the handset places additional emphasis on processor and RF PA power efficiency. Given this, one of the most useful benchmarks for a video handset should be its milliamp/hour per megabyte performance under specified channel conditions. Given that the milliamp/hour per megabyte metric effectively determines network loading and margin, this could turn out to be one of the more important measures of phone (and processor) performance. Audio Bandwidth Cost and Value There should also at least in theory be some relationship between quality and value and there is certainly a relationship between quality and delivery and storage cost. Audio bandwidth Making Telecoms Work for example is a product of the codec being used. 6 The adaptive multirate narrowband speech codec (AMR NB) for example has a sampling frequency of 8000 Hz and maps to a constant rate channel rate of 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.2 or 12.2 kbit/s. The adaptive MultiRate Wideband Speech Codec (AMR-WB) samples at 16 000 Hz and maps to a constant rate channel rate of 6.6, 8.85, 12.65, 4.25, 15.85, 18.25, 19.85, 23.05 or 23.85 kbit/s. The MPEG4 advanced audio codec samples at 48 000 Hz and can be either mono or stereo mapping to a channel rate of 24, 48, 56 or 96 kbit/s.