From microwatt to gigabit: challenges of modern radio design

Abstract

On the brink of introducing the fifth generation (5G) of cellular networks, the art of radio-frequency (RF) integrated circuit design has never seen such a wide spread of diverging requirements:On the one hand, ubiquitous sensor networks are mandating power budgets in the order of micro-watt. They should be constructed as energy-autonomous, wireless, low-cost sensor nodes. This demand is caused by massive deployment scenarios of billions of devices, which makes wires and batteries unpractical. As a result, the desire for the radio nodes to harvest their operational energy from the environment emerges.On the other hand, the recent and ongoing realization of gigabit-per-second capable cellular modems is driving hardware and power requirements to extremes. To overcome hardware limitations, introduced by analog impairments, digital correction and alignment algorithms are employed for compensation. These factors call for usage of expensive advanced CMOS technology nodes and increased utilization of digital signal processing techniques.In this paper, we recap ongoing trends and developments for ultra-low power and high-end transceiver (TRX) designs using CMOS technology nodes ranging from low-cost to highest performance.Keywords: RF; ultra-low-power; wireless architectures; transceiver; mixed-signal circuits; 5G Von Mikrowatt zu Gigabit: Herausforderungen beim Design moderner Funkübertragungssysteme. Neben der Einführung der zellularen Mobilfunknetze der fünften Generation (5G) muss sich auch die integrierte HochfrequenzSchaltungstechnik einer noch nie dagewesenen Breite an unterschiedlichen Anforderungen stellen: Auf der einen Seite gibt es überall kabellose Sensornetzwerke, denen nur eine geringe Menge an Versorgungsleistung im MikrowattBereich zur Verfügung steht. Daher müssen die Chips in diesem Bereich energieautark und möglichst kostengünstig entwickelt werden. Aufgrund der zu erwartenden hohen Stückzahlen (Milliarden von unterschiedlichsten Sensoren für verschiedene Anwendungen) sind eine drahtgebundene Energieversorgung oder der Einsatz von Batterien in vielen Fällen praktisch unmöglich. Somit wird es für die Sensoren immer wichtiger, ihre Energieversorgung aus der Umgebung zu gewinnen (Stichwort Energy Harvesting).

A Low-Power Edge-Combining Transmitter Using Quadrature Signals for FSK Modulation

“…Extending operating time, requires lowpower RF transmitters. Conventional IQ-mixing transmitter architectures suffer from high power demand due to their complexity [2]. The trend in low-power transmitter design is therefore torwards reducing modulation complexity, the number of components, and the operating frequency as summarized in [3].…”