Robert W. Brodersen - US grants

The next explosive growth in networks will come from connecting together billions of low cost, low power sensors, effectors, and smart devices. These will be communicating primarily through wireless means for reasons of mobility, ease of deployment, aesthetics, and cost. Even if such networks start out as special purpose local networks, people anticipate that they will come together in many ways. They will certainly be interconnected with each other through gateways to the broader wired Internet. The goal in this proposed project is to find the right architecture to enable Internet-like gains in the new context of wireless connectivity.

In order for wireless networks to support a wide range of applications and be suitable for mass deployment, they will need to posses the following characteristics: (1) negligible interference that allows peaceful co-existence with other independent wireless systems operating over the shared spectrum; (2) managing interference between nodes to efficiently and fairly share bandwidth; (3) dynamic and energy efficient routing and packet relaying algorithms that support mobility of network nodes; (4) scalability to support a large number of heterogeneous devices and links; (5) precise positioning capabilities to provide location information for the devices for which this is important; (6) robust and energy efficient network protocols that tolerate failure of some network nodes; (7) extremely low power wireless transceivers to ensure longevity for the energy-limited nodes; and (8) small and low cost wireless transceivers to enable widespread deployment.

This proposal is to study the above in the context of ultra-wideband (UWB) wireless signaling and multi-hop routing. Research is intended to achieve multiple objectives, Develop
(1) Efficient algorithms to determine the fundamental tradeoffs involved in tracking the positions of devices within a network of heterogeneous nodes;
(2) Robust and efficient protocols for routing digital communications within such networks and explore the fundamental capacity limits of such systems;
(3) Distributed signal processing algorithms that are network-energy and position aware to take advantage of correlations at the application layer to reduce resource consumption throughout the network hierarchy;
(4) Extremely low power, highly integrated single-chip CMOS architecture to UWB transceivers, and (5) An integrated test environment by combining an in-house FPGA-based testbed (as the digital back-end) with UWB analog front-end from AetherWire Inc. This will ultimately have approximately 30 UWB nodes from Aether Wire Inc. to test and therefore further discover issues involved with such networks.

This award includes synergistic research in fundamental communications theory and the development of novel communications technologies. To make these research activities possible the principal investigators (PIs) will establish new and enhance the existing research infrastructure for research programs associated with the Center for Information Technology Research in the Interest of Society (CITRIS) and two of its members: the Berkeley Wireless Research Center (BWRC) and the Wireless Foundations Center (WFC). The purpose of this new infrastructure is to build a research environment that enables investigation of novel technologies for cognitive radios, high data rate transmission over wireless local area networks (WLANs), and wireless sensor networks.
The wireless explosion that the researchers are witnessing today can be largely attributed to the availability of unlicensed spectrum bands. New unlicensed bands are being allocated, for example the 5GHz of spectrum available worldwide at 60GHz. At the same time, a large majority of available spectrum is locked in by its pre-allocated use in legacy systems. The PIs will investigate methods of overlaying the legacy systems with new wireless systems, which allow the use of ultra-wideband (UWB) radios to operate in the 3-10GHz band. Simultaneously, the FCC is considering allowing unlicensed 'cognitive' radios to overlay allocated bands, such as TV spectrum overlay.
This award takes a broad and thorough inter-disciplinary approach to developing the fundamental understanding of the operation in new bands, such as 60GHz and UWB, spectrum reuse and spectrum recycling by cognitive radios, together with reducing the requirements of these systems to the basic hardware specifications of the underlying technology.
The researchers are developing a common computational, test and measurement infrastructure that will allow a quantum leap in wireless technology research and its applications. By building a common computational infrastructure, consisting of compute servers, clusters of workstations and FPGA-based emulation, the researchers will foster the propagation of information from theory to prototypes. To fundamentally understand the physical properties of new bands as well as new methods of spectrum utilization and coexistence of various systems, the researchers will make a major investment in test and measurement infrastructure.
Broader Impact. This common infrastructure will support the research of over a hundred graduate students, tens of undergraduate researchers and more than ten faculty. To maximize the impact, in addition to the traditional means of publications, the research results will be disseminated through participation in communications standardization processes, participation in government and NSF-sponsored studies on wireless technology and policies, and industry involvement. Research results will be used to form new graduate and undergraduate courses that will be taught in Berkeley and elsewhere.