Advanced Doherty Power Amplifiers for 4G/5G Wireless Communication Systems

Project: Research

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In the digital era, it would seem that the use of highly inefficient linear amplification would be consigned to the rubbish bin. This would have been true if it wasn’t for the insatiable demand for high data speed, where only the more efficient data modulation formats can satisfy. These more efficient data formats require both linear amplification as well as high efficiency. The requirements in high efficiency, stems from the need for longer battery life in mobile handsets and the reduction of carbon footprint in base station transmitters. There seems to be a never ending proliferation of radio transmitters both indoors and outdoors. Operating costs are also a major factor in the demand for more efficient amplifiers which are the main consumers of electrical power. In the past efficient power amplifiers operating on class C have dictated the modulation format used such as the first generation analogue FM and the second generation GMSK which have a constant signal amplitude. Today and in the future the more efficient modulating signal format now dictates and demands a more efficient power amplifier. As the largest energy consumers in wireless communication systems, the challenge faced by power amplifier (PA) has never been greater. In modern and future systems, the more efficient modulation format signal which has higher peak average power ratio (PAPR) is adopted to give higher data speed. Typical modulation formats comprise of multi-carriers, which requires the PA in base stations to operate with high efficiency from low power to saturation. In the past this could only be achieve using the highly inefficient power amplifiers that biased in class A. The Doherty power amplifier (DPA), due to its additional efficiency peak at lower power, has become the main stream of base station PA design in the past decade. Existing DPAs cannot satisfy the strict requirements of future wireless system (including the low power and bandwidth).In this study, advanced Doherty power amplifiers for 4G/5G wireless communication systems that will meet these future requirements are proposed, studied and optimized. Although the work will centre around future 4G/5G wireless communications systems, the technique used can be applied to any other types of systems. It is envisaged that there be a large improvement in efficiency, translating to a huge reduction in both running costs as well as the carbon footprint.


Project number9042647
Grant typeGRF
Effective start/end date1/09/18 → …