eed to be realised by improving sensitivity and selectivity in the user device. From a user-experience perspective the throughput at 2.4 or 2.6 GHz will be very closely determined by distance. It can be seen that in these small-cell environments user-equipment sensitivity very directly determines the user experience in terms of distance from in this case the WiFi access point. Note that in many technical papers written both about WiFi and wide-area mobile broadband, an assumption is made that high peak data rates equate to improved energy efficiency. This may be the case sometimes but not always and is dependent on how well the power down/power up algorithms are implemented in the user equipment (a function of software latency), hardware memory effects, for example in RF power amplifiers, the efficiency of the fast memory needed to cache short data bursts and the bandwidth and characteristics of the channel over which the data is transferred. The bandwidth characteristics of the channel will also determine the amount of gain realisable from MIMO operation. Wider channel spacing, for example the 20 MHz used in WiFi and small-cell LTE deploy- ments deliver high peak rates but the noise floor proportionately increases with bandwidth. In a large noise-limited cell it is quite possible that the average data throughput with narrower chan- nel spacing, for example 3 or 5 MHz could be significantly higher than a 20-MHz channel used in the same propagation conditions and the megabyte per watt hour metric may be lower. For certain, the gain achievable from MIMO in larger cells will be marginal at best and may be neg- ative in many channel conditions due to long multipath delay and/or low signal-to-noise ratio. Making Telecoms Work It is laudable and understandable that operators should expect and want LTE to be more effective and efficient than all other forms of connectivity in all operational conditions but whether this is an achievable or fiscally sensible short-term ambition must be open to question. To get LTE to work