Christian Isheden

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The dramatic increase of network infrastructure comes at the cost of rapidly increasing energy consumption, which makes optimization of energy efficiency (EE) an important topic. Since EE is often modeled as the ratio of rate to power, we present a mathematical framework called fractional programming that provides insight into this class of optimization(More)
—Energy-efficient link adaptation is studied for transmission on a frequency-selective parallel AWGN channel. The total power dissipation model includes a circuit power that varies with the sum rate and a power amplifier efficiency that varies with the bandwidth used. The mathematical analysis provides insight into how the subcarrier rates should be chosen(More)
—Energy-efficient link adaptation is studied based on minimizing the total energy consumption per transmitted bit in a mobile terminal. It is shown that the optimal power allocation is water-filling; the optimal energy consumption per bit is a function of the power amplifier efficiency, the circuit power rate dependence, and a cutoff channel to noise ratio(More)
—Energy-efficient link adaptation is studied on a quasi-static Rayleigh fading channel assuming perfect CSI at the receiver but no CSI at the transmitter, except for the statistical characterization. Both circuit power and power dissipated in the power amplifier are considered. The energy consumption per bit is minimized over bandwidth, transmit power, and(More)
—Energy-efficient link adaptation is studied for a channel exhibiting log-normal shadow fading in addition to path loss. Both circuit power and power dissipated in the power amplifier are considered. The effective throughput per Joule of energy is maximized over transmit power and a margin for shadowing. It is demonstrated that the optimization problem can(More)
—The CoolReader project aims at designing an energy autonomous e-reader device. With the aid of photovoltaic cells adjusted to the e-reader, the device should be able to supply itself almost completely with energy from the ambient light, even in indoor lighting conditions. This way, the daily printed newspaper can be replaced by an electronic newspaper.(More)
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