LONDON — Power amplifier specialist Nujira (Cambridge, England) is claiming PAs in handsets that use its High Accuracy Tracking technology are twice as efficient during HSUPA transmissions, and 1.5 times as efficient during W-CDMA transmissions, than the same PA with a standard constant voltage (CV) supply as widely deployed in the industry today.
Tests conducted by the company were undertaken without the use of techniques such as Digital Pre-Distortion (DPD), which are employed in a base station but not a handset, and also showed that adjacent channel power ratio was over 6dB better with HAT technology.
The HAT measurements were made using an NEC transistor. For HSUPA transmissions, Nujira suggests the efficiency would be 53 percent for the HAT based PA solution, compared to 25 percent for the fixed voltage supply method, the current industry standard.
For W-CDMA transmissions, the efficiency would be 60 percent for the HAT PA, and 40 percent for fixed voltage " an improvement of 36 percent.
According to Julian Hildersley, recently appointed VP of Handset Development for Nujira, the results vindicate the company's theoretical assumptions that "the benefits of HAT scale down to the lower power levels of the handset environment. Our measurements were made using a handset PA and demonstrate clearly that the substantial efficiency gains achieved in the network are also realized in the handset. "
Hildersley told EE Times Europe Nujira is working with several "partners" that he would not name but who are evaluating its IP, and expects several of these to design this into handset PAs.
The Coolteq PA technology for handsets — an extension of Nujira's market base which so far has been the wireless infrastructure and basestation segments — is scheduled to be unveiled at the Mobile World Congress in February at Barcelona, Spain.
"Our results clearly indicate that a grossly non-linear PA can exhibit superior adjacent channel performance than a conventional PA," added Hildersley.
He noted the RF challenge in a 4G multi-standard handset is the creation of a broadband network air interface that will work around the world within the size, power and cost constraints of a compact portable device.
Hildersley added handset makers can realize significant battery life improvements in their production terminals by integrating Nujira's modulators. "In addition, they can achieve a bill of materials cost saving by using a smaller number of wide-band PA devices. We estimate that, by adding Coolteq, the number of PAs required to cover all the LTE frequency bands licensed worldwide can be reduced from seven to two."
He added Nujira anticipates the first handsets likely to include its analog circuitry design will be models capable of HSPA upload and download technology.
Hildersley noted the company's business model for supplying IP to handset PA makers will be "flexible", but "we are still working on that."
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