dband connectivity. Time dispersion becomes a particular challenge at higher data rates. 1 LTE stands for long-term evolution and is the generic term used by the industry to describe the next generation of OFDM-based cellular radio networks. Making Telecoms Work: From Technical Innovation to Commercial Success, First Edition. Geoff Varrall. © 2012 John Wiley & Sons, Ltd. Published 2012 by John Wiley & Sons, Ltd. Making Telecoms Work One of the narratives of this book is that our ability to process signals in both the frequency and time domain has translated/transformed this challenge into an opportunity by increasing the user experience value realisable from mobile broadband access faster than other access media. This is different from what has happened in the past. In the past, any increase in data rate in wireless systems has been matched by an equivalent increase in the data rates achievable over fibre, cable or copper. This is no longer the case. The business of mobile broadband is being transformed by transforms. The extent of the transformation, however, is as yet unclear - this is work in progress. For example, we can show that present LTE devices can deliver high peak data rates on a single- user basis but power efficiency has not improved on a pro rata basis. Sending data faster may result in a system efficiency improvement but this is not the same as a power-efficiency improvement. Power efficiency for the single-user experience has to improve in order to realise added value. This could be achieved by increasing network density but this increases capital and operational cost, SO the user will need to be charged more for access. Similarly, the high per user data rates have an associated cost that is inflicted on other users. If the other users either do not notice or do not mind then that is fine. If they do notice and/or mind then this is effectively a loss of added value and an increase in opportunity cost. It is pointless increasing single-user value if multiple-user value decreases by an equivalent o