Electronics Weekly
In an opinion piece for Electronics Weekly, head of Nujira Tim Haynes writes that the launch of LTE has met with some power problems. As such, it has not been all that different to that of 3G some ten years. Then as now, power was a major concern as handset designers had not optimised their products and were also waiting on improved digital technology to deliver more efficient signal processing. This time, although the digital section has once again leapt in complexity, one of the culprits behind the increased power consumption is the power section. As the developer of an envelope-tracking technology, Haynes naturally sees this as one solution to the problem and recovering some of the efficiency lost in the move from narrowband to broadband power amplifiers.
However, as with digital signal processing, increased parallelism is also a slightly counter-intuitive answer, as I cover in this piece on RF technologies for New Electronics‘ Tech Watch section. A big issue is the peak-to-average power ratio of these new, complex modulation schemes. It is hard to make one amplifier cover the range with high efficiency. However, by using multiple amplifiers, such as Doherty circuits, in parallel, it is possible to meet the high peak power demand and still keep each operating in its peak-efficiency zone. Engineers from Pohang University of Science and Technology in Korea have suggested that, under ideal conditions, a five-way design could be useful, although their work has so far resulted in just a three-way implementation that was tuned for wideband-CDMA protocols. As the LTE protocols evolve, we can expect to see a lot more focus on the analogue as well as digital processing in the struggle to boost battery life.
