Tag Archives: 5G/6G

Index Modulation Explained

Wireless researchers are continuously exploring ways to increase the spectral efficiency (bits/sec/Hz) and energy efficiency (bits/Joule) of wireless communication systems [1]. Spectral efficiency can generally be improved by using larger constellations or by using multiple antennas at the transmitter and receiver, better known as MIMO. But increasing energy efficiency is not that straightforward. Let’s consider this in bit more detail.

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Reconfigurable Intelligent Surfaces Explained

Wireless channel is inherently unpredictable and this results in loss of information as it travels from the transmitter to the receiver. The main reason for this is that multiple copies of the wireless signal arrive at the receiver which sometimes add constructively and at other times destructively, causing deep fades. The deciding factor between signal copies (think of them as echoes) adding constructively or destructively is the relative phase. If the phases are aligned the signals add up but if the phases are not aligned, we get a fade (fades can be as deep as 60-80dB). Wireless engineers over the years have worked around this problem by using multiple antennas also called antenna arrays.

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What is Energy Harvesting

Conventional battery powered systems can be impractical, expensive, or have negative environmental impacts. Energy harvesting (EH) offers a potential solution to these problems. Through ambient sources such as solar, vibrational, thermal, and RF, self-sustaining IoT devices can be designed. These devices can be easily implemented in wearables, medical implants, and infrastructure. Companies such as TI and ADI have developed power management systems for EH and consumer products already exist. These products continue to increase in efficiency and practicality every year.  

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