In a digital communication system, the analog signal that the receiver receives with its radio frequency front end is converted into digital format by using the analog‐to‐digital converter (A/D converter, ADC). Quantisation takes place during the conversion from continuous amplitude signal to discrete amplitude signal, leading inevitably to losses in information which are dependent on the number of bits that is used to represent each sample. Although employing a higher bit resolution reduces the quantisation error, a higher power dissipation of the ADC is incurred at the same time. This trade‐off is essential to the energy efficiency of the receiver, which is commonly measured by the number of information bits conveyed per consumed Joule of energy. We investigate, in this work, the adaptation of ADC resolutions of a multi‐antenna receiver based on instantaneous channel knowledge, with the goal of maximising receiver energy efficiency. The formulated optimisation is a combinatorial problem, and we propose several algorithms which yield near‐optimal solutions. Results from numerical simulations are presented and analysed, which provide guidelines to operation and deployment of the system. Copyright © 2014 John Wiley & Sons, Ltd.

Being sensitive to carrier frequency offset (CFO) is known to be one of the main drawbacks of multi carrier systems. In this paper, the effects of CFO on a filter bank based multicarrier system (FBMC) in a multipath fading channel are discussed, where an ideal root-raised cosine (RRC) filter with roll-off factor 1 is used as the prototype filter which enables analytical derivations of the interference caused by the CFO. Based on these results, an approximation on the SNR degradation with very small CFO is also given. Numerical experiments as well as Monte Carlo simulations are done to verify the analysis and the accuracy of the approximation in FBMC systems. A comparison with the SNR degradations in cyclic prefix based orthogonal frequency division multiplexing (CP-OFDM) sys tems has indicated an advantage of FBMC systems as being more robust to frequency misalignments.

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