Prof Sunil Maharaj, Dean of the Faculty of Engineering, Built Environment and Information Technology (EBIT), and one of his students, Mr Pandelani Munyai, won the Best Paper Award at the 2015 Institute of Electrical and Electronics Engineers (IEEE) Africon Conference, which was held at the United Nations (UNECA) Conference Centre in Addis Ababa, Ethiopia from 14–17 September. Approximately 400 internationally peer-reviewed technical papers from across the world were presented.

The title of the paper presented by Prof Maharaj and Mr Munyai was ‘On the improvement of phase noise errors in wireless communication systems’. Mr Pandelani Munyai is currently studying towards a master’s degree in Electronic Engineering and this paper is based on a part of his research.  

Modern wireless communication systems, such as 5G and today’s 4G LTE (long-term evolution) are expected to deliver higher data rates. However, their performance is heavily impacted by the emergence of phase noise (PN) in the transceivers. In fact, PN has become an integral part of the frequency synthesiser design. In the process of generating carrier waves, the local oscillators of the frequency synthesisers generate an unwanted phase noise that limits the performance of the transceivers. Despite several research advances that sought to mitigate and suppress phase noise errors in radio transceivers, phase noise remains a major problem and limits the performance of wireless communication systems. Phase noise is caused mainly by the oscillators’ inability to produce a single and clean frequency without spurious tones and harmonics.

In this paper, Mr Munyai presents a modified fractional-phase locked-loop frequency synthesiser (FPLL FS) architecture that is capable of suppressing unwanted spurs. Simulation results show that the proposed model achieves a significantly low level of phase noise, which is below the −145dBc/Hz announced in recent literature, and has only minimal spurious tones in the frequency of interest. The system design and simulations achieved a better signal-to-noise ratio (SNR) than that required by the LTE release 8 specifications for the specified modulation schemes.

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