One day 4G networks will enable mobile users to access streaming media in real time over a 100Mbps network. But before the LTE technology on which fourth-generation networks are based can be deployed, operators and handset makers need to tackle the problem of power consumption.
Experts say 4G networks will require more electrical power compared to today's 3G technology - this means shorter battery life on handsets and higher power mobile basestations.
Unlike the 3G mobile phone system, which uses quad-band technology (800/850/1,900/2,100MHz), LTE supports 23 frequencies.
Each frequency needs a device called a power amplifier, which boost radio signals that wirelessly link handsets to mobile phone masts. The greater the number of frequencies a device supports, the more power amplifiers are needed, which impacts electricity consumption.
Smartphones generally use more power compared to ordinary mobile phones. This is why iPhone users today are only able to get a day's worth of power before the handset battery dies.
LTE-based 4G dongles that plug into laptop USB ports may also face a serious design impact. This is because the USB specification limits the amount of power a device can use to 500 milli amps, which may not be enough to get the full bandwidth boost offered by LTE.
Cambridge startup Nujira has developed power amplifier technology which it claims is far more efficient than existing designs. There is a version for the basestation, and a miniature power amplifier for the handset.
"Our [power amplifier] modules halve power consumption," says Jeremy Hendy, vice-president of sales and marketing at Nujira. The power savings are achieved using a smart power supply that is able to map power to the shape of the radio wave. The company is showing the technology at Mobile World Congress.
This was first published in February 2010