Improving Energy-efficiency of Multi-antenna Receivers via Adaptation of ADC Resolutions

Konferenz: European Wireless 2014 - 20th European Wireless Conference
14.05.2014 - 16.05.2014 in Barcelona, Spain

Tagungsband: European Wireless 2014

Seiten: 6Sprache: EnglischTyp: PDF

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Bai, Qing; Nossek, Josef A. (Institute for Circuit Theory and Signal Processing, Technische Universitaet Muenchen, Munich, Germany)

The energy-efficiency of a receiver, which we measure in this work by the number of information bits conveyed per Joule of energy consumption at the receiver, is greatly influenced by the design and bit resolution of the analog-todigital converter (ADC) it employs. For a given ADC, using higher resolution leads to less quantization error in the digitized receive signal, yet requires a larger power dissipation. This trade-off can be utilized to maximize the energy-efficiency by adapting the ADC resolution according to the state of the communication channel. For a receiver with multiple antennas, the resolution of ADC associated with each antenna can be jointly adapted, leading to a multivariate integer programming problem which is difficult to solve to optimality. We propose several adaptation strategies which differ in complexity and the amount of online computations, and compare their performances based on the simulation results. Furthermore, we show that equipping the receiver with more antennas is beneficial to its energy-efficiency when only a subset of antennas associated with relatively good channel conditions is chosen for reception, and an appropriate ADC resolution is employed for the quantization of receive signals. As the improvement in energy-efficiency falls off with increasing number of antennas, a cost-effective antenna number can be determined by the receiver, depending on the application scenario and the physical limitations on the device.