EARS: Photonically-Enabled Extremely Wideband Compressive Wireless Spectrum Sensing

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Abstract Title: EARS: Photonically-Enabled Extremely Wideband Compressive Wireless Spectrum Sensing Institution: Johns Hopkins University Abstract: Nontechnical With its multitude of uses in wireless communications and sensing, the radio spectrum is a highly regulated and finite resource. At present the radio spectrum is tightly and statically allocated and modern electronic systems are increasingly relying on high-bandwidth wireless communications for internet connectivity as well as inter-device communications. While the radio spectrum is tightly allocated, investigations indicate that the usage at any location and time is generally sparse with a limited number of active channels, scattered across an extremely broad spectral range. This observation indicates that a radio system that can efficiently and rapidly sense spectral usage could adapt to exploit these temporary spectral opportunities and thus make more efficient use of the finite radio spectrum resource. The key technology for such a system is wideband spectrum sensing and this technology must be implemented rapidly with minimal hardware resources. This program will develop an extremely wideband, compact, and robust spectrum sensing system for the microwave through millimeter-wave frequency bands to facilitate efficient high-bandwidth communications and high-resolution sensing in future mobile electronic systems. This program will also provide research opportunities for undergraduate and high-school students as well as develop educational tools, for example interactive on-line teaching applications, and facilitate outreach activities, for example through the Johns Hopkins University Women in Science and Engineering (WISE) and STEM Achievement in Baltimore Elementary Schools (SABES) programs, that target underrepresented groups in the STEM fields. Technical Recently, the framework of compressive sensing (CS) emerged as a promising method to efficiently capture signals that are sparse in some domain with significantly fewer measurements than would be traditionally necessary permitting faster, simpler, and/or lower power sensing. The wideband spectrum is inherently sparse due to its spectrum under-utilization at any given spatiotemporal location. Hence, CS emerges as a promising candidate to realize effective low-cost wideband spectrum sensing. The extremely wideband spectrum sensing necessary for cognitive radios in the microwave and mm-wave will necessitate photonic solutions, since the instantaneous bandwidths (potentially 300 GHz) are simply too large and spectral opportunities too short lived for traditional electronic sampling hardware. This research program will demonstrate a new approach for compressive photonic sampling that addresses these shortcomings by performing much of the signal processing in the photonic domain. More specifically, this program will develop an extremely wideband chip-scale spectrum sensing architecture by combining the benefits of high-speed integrated photonics with recently developed photonic-domain compressive sensing. Through the union of these technological advancements with algorithmic advancements tailored to the unique capabilities of this hardware, an extremely wideband spectrum sensing system will be proven to facilitate cognitive radio systems in the microwave and mm-wave ranges of the wireless spectrum. This architecture allows for extremely rapid collection of compressive sensing measurements and compressive sensing theory and algorithms will be developed to take advantage of this unique capability. Such a system is greatly needed to address the high information capacity and efficient spectral usage expected by future wireless electronic devices.