general information
research areas
research groups

Organizationally, STAR Lab is a research group within the Department of Electrical Engineering of Stanford University. The Laboratory is composed of eight regular faculty, a number of emeritus faculty with active research programs, three consulting professors, several research associates, and more than sixty graduate students and staff.

Research areas in the STAR Lab include electromagnetics and remote sensing, communications, and signal processing.

Electromagnetics and Remote Sensing
Research in electromagnetics and remote sensing offers a variety of means for learning about the natural environment. Measurements using radio signals traveling between the ground and NASA planetary spacecraft are used to study planetary atmospheres, ionospheres (the ionized gases that surround planets), surfaces, and ring systems, resulting in an important, precise source of information on these objects. The geophysical properties of planetary surfaces are inferred from carom signals traveling between orbiting spacecraft and the earth via the surfaces of the planets. Professors and students are active in many of NASA's current planetary missions. The experimental program motivates and is supported by ongoing theoretical work in advanced theories of wave propagation and scattering. These theoretical and experimental programs are supported by active research in the area of signal processing and efficient techniques in using digital processors.

In recent years, the Ultra Low Power Group has developed technology that allows processors to operate 100 to 1000 times more efficiently than standard CMOS. Work is being done at the algorithm, architecture, circuit, device, and VLSI processing levels to achieve these high efficiencies. As an example, the group recently produced the world's most energy-efficient 1024-point FFT processor.

Members of the laboratory are also engaged in very low frequency research into the origin and properties of electromagnetic signals in the Earth's environment, their interactions with the energetic particles in the earth's radiation belts, their effects on the ionosphere, and their relation to other phenomena on and below the Earth's surface, in the upper atmosphere, and in interplanetary space. Of particular recent interest is the investigation of lightning discharges and their effects on the earth's near space environment. Both natural and man-made signals are studied in this research. Measurements are taken at a number of locations around the wor ld, including Alaska, Greenland and the Antarctic.

Measurements in the Ultra Low Frequency (ULF) range have recently led to the discovery that major earthquakes may be preceded by low-frequency electromagnetic signals. As a result, additional measurement systems are being built and installed along the San Andreas fault in California. This research has become a cooperative effort with the School of Earth Sciences.

Research, pioneered at Stanford, is also ongoing in the further development of radar remote sensing of ocean waves and current systems. Cooperative research in this area is underway with faculty members in the School of Earth Sciences.

STAR Lab maintains a variety of experimental research laboratories equipped with state-of-the-art test and measurement equipment including systems and workstations for use in signal and data analysis. Several of these machines are equipped with graphics capabilities as well as software tools for system and VLSI hardware design.

Wireless technology has enormous potential to change the way people and things communicate. Future wireless networks will allow people on the move to communicate with anyone, anywhere, at any time, using a range of multimedia services. Wireless communications will also enable a new class of intelligent home electronics that can interact with each other and with the Internet. A wireless communications infrastructure is also needed for automated highways and for sensor networks, and wireless video will support applications such as distance learning and remote medicine. There are many technical challenges that must be met in order to make this vision a reality. These challenges transcend all levels of the overall system design, including hardware, communication link design, and networking. In addition, synergies between the hardware, link, and network designs must be exploited in order to meet the demanding performance requirements of these future systems. STAR Lab faculty are actively pursuing research in these areas, with specific focus on capacity limits of wireless systems and networks, protocol design and analysis for wireless cellular systems and ad hoc networks, sensor network design, wireless communications for distributed control, energy-constrained communications, and dynamic resource allocation in wireless systems.

Broadband Access
STAR Lab faculty also research the infrastructure and supporting methods to bring broadband access, typically 100 Mb/s, to all users of the internet, residential or commercial. Such high-speed connectivity may occur over wireline optical or copper links or via wireless links, or more likely combinations of all three. Such speed mandates deep investigation and understanding of the fundamental limits of communications networks and transmission media. Topics such as modulation, coding, information theory, signal processing, networking theory, multiple antennas, and other forms of diversity, are mainstream interests within the STAR Lab faculty who address the broadband access area.

Professor Cioffi's group has one specific focus on high speed transmission on copper twisted pair, with focus on modem technologies for single or multiple users. This area is known as digital subscriber lines. The current work investigates methods and bounds for multiple users within a binder of crosstalking telephone lines, which is one of the most challenging and difficult transmission problems ever studied by information theorists and communication theorists. Typically projects span the range of creating new information-theoretic bounds for multiple-users of a communication system to design and analysis of functional models for very high-speed transmission. The group has worked with many companies to demonstrate 100 Mb/s and higher-speed transmission over 100's of meters of single-twisted-pair.

Optical Communications
Optical communications is a fascinating, interdisciplinary field that lies at the intersection of classical optics, quantum electronics, high-speed circuits and communication theory. It is no surprise that this field has attracted some of the greatest scientists and engineers of this generation. The current Internet owes its existence to optical communications, and the future growth of communication at all scales will depend increasingly on advances in optical techniques.

While wide- and metropolitan-area networks have achieved terabit-per-second capacities, much work remains to further increase capacity and make these networks more flexible and robust. Perhaps the grand challenge of the next decade lies in providing economical access at high speeds (100 Mb/s) to every home, business and classroom. In local-area networks, new approaches are required to scale Ethernet speeds to 10 Gb/s and then 100 Gb/s. At a still smaller scale, optical communications is being used to overcome interconnection bottlenecks in computer backplanes and even at the chip scale.

Optical communication research in STAR Lab spans a wide range of disciplines, including basic physics, optical devices, digital and analog communication techniques, and networks. Optical media being studied include single-mode fiber, multi-mode fiber and free-space links.

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