Nujira supports up to 16 LTE bands in handsets
UK firm's envelope tracking technology can enable multiband, multimode power amplifiers with low energy consumption
Published: 11 February, 2013
UK-based Nujira has been working for five years to get the technology it supports, Envelope Tracking, into mass market devices, to address the challenges of LTE's fragmented spectrum bands. It will reach this goal next year, the firm claims, as it prepares to launch Woodstock, a reference design for smartphone RF front ends, which can support 16 frequencies while keeping power consumption low.
This technology will turn up in commercial smartphones in 2014, said CEO Tim Haynes, but major chip providers could be hard on Nujira's heels. In ET chips for base stations, the firm has mainly adopted a licensing model and is sure to be keeping an eye on its 200-odd patents in this technology.
Meanwhile, Woodstock is based on Nujira's recently launched NCT-L1200 ET chip, and covers up to 16 bands from 700MHz to 2.7GHz in a printed circuit measuring under 200 square millimetres, as well as 3G and GSM as well as LTE.
LTE is today deployed in 20 frequencies between 700MHz and 2.7GHz, and currently, each one requires its own power amplifier (PA) and RF filter. Nujira can apply its ET supply modulator to PAs from different chip suppliers, and in Woodstock three of these are supported at once - a multimode, multiband PA; a 2.3-2.7GHz PA; and a region or operator specific LTE PA. Also included in the reference design are antenna switches and filters. The firm says all the major PA vendors have now developed ET-capable products.
"Adding envelope tracking to a couple of specific LTE bands is relatively straightforward, but doesn't by itself solve the cost, footprint and power consumption challenges the industry is facing," Haynes said. "What the mobile industry really needs is multimode, multiband reference designs that can be quickly incorporated into handsets."
The energy saving comes because the ET modulator chip can drive up to four PA devices in parallel even on 20MHz LTE channels. And it enables the handset to deliver full power to the antenna port, maximizing coverage and boosting data rates, even for LTE signals with high PAPR (peak to average power ratios).
Nujira says a dozen chipset vendors are now using the ET interfaces it has pushed as a way to standardize this sector - OpenET and MIPI.
However, with the frequency fragmentation of LTE becoming a big issue for device makers, ET will start to catch the attention of large chip firms as it enters the mainstream. Qualcomm, Texas Instruments and RFMD are all reported to be developing ET products and Nujira will be keeping an eye on its intellectual property rights. Haynes said in an interview with Electronics Weekly: "We know there are two ways to do envelope tracking, our patented way and one other less efficient way. We will be looking at these other vendors' chips very closely with an oscilloscope and a microscope when they come on the market."
He said in a statement: "Nujira is the only ET vendor with the ability to support our customers with these complex, leading edge RF reference designs. Our new reference design provides vendors with a rapid solution for single-SKU global 4G handsets which can beat today's 3G phones on cost, size, RF performance and power consumption."