5
Impact and Digital Suppression of Oscillator Phase Noise in Radio Communications
5.1 Introduction
Building compact-size and low-cost yet high-performance, flexible and reconfigurable radio transceivers for future wireless systems is generally a very challenging task. Using dedicated hardware particularly designed and optimized for only a single application or part of the radio spectrum yields only limited solutions, especially in terms of radio flexibility and re-configurability. Also, to keep the overall size and cost of the radio parts feasible, especially in multiantenna multiradio scenarios, the cost and size of individual radios are strongly limited. This implies that various circuit imperfections and impairments are expected to take place in the used radio transceivers, especially in the radio frequency (RF) analogue electronics [10]. This is also further catalysed by decreasing supply voltages and increasing electronics miniaturization. This is discussed at a general level, for example in References [1] to [4]. Good examples of such RF imperfections are, for example, mirror-frequency interference due to I and Q branch amplitude and phase mismatches (I/Q imbalance), intermodulation and harmonic distortion due to mixer and amplifier nonlinearities, timing jitter and nonlinearities in sampling and analogue-to-digital (A/D) ...
