The Hardware Enablers for the Internet of Things - Part I
The premise of the Internet of Things (IoT) is that this new technology trend will connect billions of devices using the internet starting around 2020, with ecosystems that will address wearables, smart home, automotive, smart cities, the workspace and industrial applications. The IoT system consists of three domains: Sensors, Connectivity and Applications. Most attention for IoT has been focused on the applications for the home (consumer), transport (mobility), health (body), buildings (infrastructure), factory (industrial) and cities (utilities, security). What is missing from much of the discussion are the underlying hardware and sensor technologies that enables the IoT applications, intelligence and links to the 'cloud'.
In Part I of this article, the relationship between hardware and applications is discussed as well as the challenge hardware engineers face in meeting the IoT requirements.
What we must remember is that it is the underlying hardware that enables the sensing functions that bring the 'smartness' to the devices and the wireless transmission of data between devices and the backend intelligence that act on the acquired sensor data (temperature, pressure, speed, acceleration, GPS location, heartbeat rate, respiration rate, energy consumption, etc.) to bring about a response that optimizes productivity, conservation, and better quality of life. There are many challenges that the hardware community must meet to invent new devices and technologies that must be smaller, lighter, more efficient and lower cost than ever before if the Internet of Things revolution is to happen with all the heightened expectations.
Entering the domain of microwave engineering
Information from the transmitter node travels down from its application layer (OSI Layer 7) down to the PHY layer (OSI layer 1) where the data bit stream is translated into physical variations in voltages and current waveforms, which are sent across the physical transmission medium to the receiver node. At the receiver node, the modulated signals are converted back into a digital bit stream and relayed back up its layer stack to the consumer’s application layer. The medium can be air, copper, optical fiber cable or any other materials, which can carry 'waves'.
In the RF Front-End, microwave low-noise amplifiers (LNAs) and power amplifiers (PAs) are used to receive/send the modulated RF carrier signals from one node to another by propagating the radio wave through an antenna. Just behind the RF section, the signals are up- and down-converted from baseband using mixers. Distances traveled can be as short as 1 meter or as far as 35,800 km (the distance from ground to a geostationary satellite.)
Common wireless communications systems that operate in the microwave frequency range include IEEE 802.11 (WiFi), Bluetooth, NFC, cellular and satellite communications at C-, Ku- and Ka-bands. Communications equipment used to be bulky, stationary and plugged into the wall for power. The application layer demands for high data-rate, low latencies, error-free transmission, long battery life and high capacities of multi-user scenarios have led to the current state-of-the-art in mobile handsets.
A new paradigm for communications hardware
The size, weight, power and cost (SWaP-C) demands for the IoT ecosystems will force the creation of a new paradigm for the hardware. These metrics must be improved by factors of 10 to 100 in order to make IoT realizable. If today’s hardware costs $10 a piece for a 100 million device market, then the same function may have to be well under $1 to address a 20 to 50 billion device market. Most electrical devices today have ready access to prime power to energize their circuits. In the IoT world, there are many use cases where connecting the device to the wall outlet or changing / charging the battery is a showstopper. Therefore, improved power efficiency, smart power management, energy harvesting and wireless power transmission will all need to be investigated and made viable for IoT applications. In today’s hardware, milliwatt dissipation may be sufficient. In the IoT world of 2020, microwatts or even nanowatt power dissipation will be required. In many sensor applications, the IoT device must operate at a very low duty cycle; waking up for milliseconds to perform its function, transmit its data payload and then go back to sleep.
The good news is that the advanced silicon CMOS technologies being developed today in the world's leading foundries feature sizes ranging from 32nm down to 10nm. The design of the next generation of low-power RF transceivers, mixed-signal ADCs/DACs and micro-controllers will not be easy nor is first-pass design success assured. Even more challenging will be the design and fabrication of packaging, inter-connects and PWB to meet the same IoT metrics. EDA CAD tools must also evolve to design, simulate and lay out the highly integrated microsystems and IoT System-on-a-Chip (SOCs) realizations. There has been much discussion about the end of Moore’s Law as we approach 10nm geometries, but this may be overstated.
Other important IC technologies that will need attention include power converters, micro-controllers such as Raspberry Pi, ARM, Arduino and Intel’s Edison platform. Many traditional hardware vendors such as Freescale, Intel, TI, Broadcom, Qualcomm, STMicroelectronics and Samsung are all actively promoting their own IoT hardware ecosystems for the marketplace. Many consortia are being formed.
For further readings on the development of advanced semiconductor technologies for IoT, please read the International Technology Roadmap for Semiconductors (ITRS) found here.
In Part II, the state of sensor technologies for IoT will be discussed. It is the sensors that provide situational awareness and inputs to make our IoT intelligent'. It is also interesting to note that sensor technology does not follow Moore’s Law and is often described as “More than Moore’s Law”.
Timothy Lee is the 2015 IEEE Microwave Theory and Techniques Society (MTT-S) President. Currently he is a Boeing Technical Fellow, working in Boeing Research and Technology in Southern California. He has over 35 years' experience in the design of MMICs, microwave components and sub-systems for electronic systems. His interests in IEEE MTT-S include the continued excellence of technical journals and conferences for the microwave engineering communities worldwide and the development of microwave/wireless solutions to benefit humanitarian needs.
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