Low-Power High-Performance Wireless Devices for Massive Connectivity A. Lee Swindlehurst and Michael Green University of California Irvine
The so-called "Internet of Things'' (IoT) refers to the inter-networking of all types of physical devices in order to allow them to collect data and communicate with one another, or with an access point that allows them to exchange data with the internet and hence the entire world. There is a plethora of applications where such devices could be useful, including medicine, transportation, civil infrastructure, environmental monitoring, as well as personal communications. The ability of these devices to sense their environment and communicate with each other and the internet will lead to a revolution that will improve our health, our environment and our overall quality of life. In order for the IoT revolution to become a reality, significant advances are needed to reduce the cost of these devices (so that they can be deployed ubiquitously) as well as their energy consumption (so that they can operate for long periods of time without replacement). Advances in digital hardware over the past decades has resulted in circuit miniaturization that has in turn allowed for complicated microprocessors with billions of transistors to occupy a space no bigger than the head of a pin. Advances in nanofabrication have allowed for the creation of tiny sensors and actuators that require only very small amounts of energy or minimal access to their environment in order to operate. However, the physical constraints associated with analog electronic conversion, amplification and communication have been slower to be overcome. The goal of this project is to help remedy this gap, and develop simple, low-power, low-complexity radio-frequency devices that can be used in conjunction with sophisticated software to enable the IoT vision to become a reality.
New techniques and hardware implementations are needed that reduce the size, cost and power consumption of transceivers that will enable ubiquitous deployment of IoT devices as well as energy efficient gigabit-per-second wireless networks. Motivated by this vision, our project focuses on several new research initiatives that will push wireless systems in this direction: (1) A new concept for massive MIMO RF hardware based on reconfigurable one-bit direct detection (DDA) antennas that potentially require neither mixers nor local oscillator generation and distribution, and enable simpler antenna feeding, high energy efficiency, lower cost and ultrafast signaling; (2) New integrated circuit implementations based on inductor tuning to validate the DDA concept and illustrate how mixer-less demodulation via wireless LO distribution can be used to dramatically simplify the RF front end for millimeter-wave frequency bands; (3) Uplink/downlink channel capacity results with one-bit ADCs/DACs that do not rely on the assumption of white quantization noise, based on a new derivation in the angular frequency domain. These results will be better suited for millimeter-wave channels that tend to be sparse and frequency-selective. (4) New types of finite field downlink precoders with one-bit DACs that do not require the standard arithmetic operations of multiplication and addition (and hence considerably simplify the necessary digital computations), and yet still substantially outperform conventional methods and can be combined with channel coding techniques; (5) More realistic models for low-resolution ADC and DAC hardware that account for out-of-band emissions and intermodulation products in the data, in order to determine under what conditions they can be ignored and how they can be mitigated otherwise. The anticipated research addresses critical challenges for next-generation wireless systems and is also of high relevance for the success of low-power IoT technology.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
