Electrical engineers from University of California San Diego (UCSD) are building the foundations for wireless networks of the future. Hoping to bring mass access to the the kind of high capacity, extremely low power wireless networks found only in expensive defense and satellite applications, the researchers are merging silicon chip technologies with sophisticated wireless communications tools in the millimeter and microwave range. This work, according to UCSD, could result in personal wireless networks that make current high-speed wireless connections feel slower than the dial-up connections from the early 1990s.
"On-demand video delivered wirelessly is a tidal wave that is sweeping through communications networks on a worldwide basis, and it creates tremendous technical challenges at all layers of the network,” said Lawrence Larson, Professor and Chair, Department of Electrical and Computer Engineering (ECE) at the UCSD Jacobs School of Engineering. “In order to accommodate this soaring demand, wireless communications devices will have to operate at higher frequencies and wider bandwidths in order to supply the data.”
The UCSD electrical engineers are working on wireless communications devices that operate at higher frequencies and wider bandwidths than current consumer technologies.
One of the keys to this progress is advances in silicon circuit technologies that enable silicon based circuits to operate at millimeter and microwave frequencies.
“The UCSD circuits groups are making microwave and millimeter-wave circuits and systems that are approaching the complexity of a microprocessor and allowing flexibility and functionality for communications that currently is not available,” said electrical engineering professor James Buckwalter.
Advanced radio-frequency CMOS chips from the Rebeiz lab, and a silicon-based millimeter wave amplifier that works at 60-120GHz (the Cascaded Constructive Wave Amplifier) from the Buckwalter lab are just two examples. These kinds of projects are moving toward inexpensive, silicon-based wireless communications links in millimeter and microwave frequency range that can support data transfer rates as fast as 10Gbps over a kilometer.
“In our labs, we work on advanced radio-frequency CMOS chips, planar antennas, and system-level design so as to result in 10 to 100 times faster data transfers at the same energy consumption. This is done using phased arrays, efficient power amplifiers, very low-noise receivers, and advanced packaging technologies. Systems developed at UCSD have demonstrated data transfer up to 6Gbps, which is 12 times faster than the best USB protocols,” said electrical engineering professor Gabriel Rebeiz.
Other engineers are making amplifiers more linear and more power efficient. Improving the linearity of amplifiers can allow for the packing of more bits per hertz (Hz) of bandwidth.
“Visualize the link between the cell phone tower and your smartphone as a straw,” said Lawrence Larson, who leads the RFIC group. “That only lets a limited amount of data through at any one time. In the next few years, we are trying to turn the straw into a fire hose.”
The engineers from the Department of Electrical and Computer Engineering (ECE) will be presenting 23 papers at two premier annual conferences that focus on advanced wireless communications technologies - IMS 2010 and RFIC 2010. IMS is the IEEE International Microwave Symposium and RFIC is the IEEE Radio Frequency Integrated Circuits Symposium.