Showing papers by "Theodore S. Rappaport published in 2009"

On-chip integrated antenna structures in CMOS for 60 GHz WPAN systems

Abstract: This paper presents several on-chip antenna structures that may be fabricated with standard CMOS technology for use at millimeter wave frequencies. On-chip antennas for wireless personal area networks (WPANs) promise to reduce interconnection losses and greatly reduce wireless transceiver costs, while providing unprecedented flexibility for device manufacturers. This paper presents the current state of research in on-chip integrated antennas, highlights several pitfalls and challenges for on-chip design, modeling, and measurement, and proposes several antenna structures that derive from the microwave microstrip and amateur radio art. This paper also describes an experimental test apparatus for performing measurements on RFIC systems with on-chip antennas developed at The University of Texas at Austin.

On-Chip Integrated Antenna Structures in CMOS for 60 GHz WPAN Systems

Abstract: We present several on-chip antenna structures that may be fabricated with standard CMOS technology for use at millimeter wave frequencies. On-chip antennas for wireless personal area networks (WPANs) promise to reduce interconnection losses and greatly reduce wireless transceiver costs, while providing unprecedented flexibility for device manufacturers. We present the current state of research in on-chip integrated antennas, highlight several pitfalls and challenges for on-chip design, modeling, and measurement, and propose several antenna structures that derive from the microwave and HF communication fields. We also describe an experimental test apparatus for performing measurements on RFIC systems with on-chip antennas at The University of Texas at Austin.

Site-Specific Knowledge and Interference Measurement for Improving Frequency Allocations in Wireless Networks

Abstract: We present new frequency allocation schemes for wireless networks and show that they outperform all other published work. Two categories of schemes are presented: 1) those purely based on measurements and 2) those that use site-specific knowledge, which refers to knowledge of building layouts, the locations and electrical properties of access points (APs), users, and physical objects. In our site-specific knowledge-based algorithms, a central network controller communicates with all APs and has site-specific knowledge so that it can a priori predict the received power from any transmitter to any receiver. Optimal frequency assignments are based on predicted powers to minimize interference and maximize throughput. In our measurement-based algorithms, clients periodically report in situ interference measurements to their associated APs; then, the APs' frequency allocations are adjusted based on the reported measurements. Unlike other work, we minimize interference seen by both users and APs, use a physical model rather than a binary model for interference, and mitigate the impact of rogue interference. Our algorithms consistently yield high throughput gains, irrespective of the network topology, AP activity level, number of APs, rogue interferers, and available channels. Our algorithms outperform the best published work by 18.5%, 97.6%, and 1180% for median, 25th percentile, and 15th percentile user throughputs, respectively.

Realizing Gbps wireless personal area networks - guest editorial

Abstract: The 19 papers in this special issue focus on the push beyond giga-bit-per-second (Gbps) data rates, in order to more rapidly access data on personal devices, as well as potentially replace all the cables going into a device, including the video cable. This issue beings together the state-of-the-art, across multiple disciplines, for achieving Gbps WPAN capability.

Frequency-Domain Channel Estimation and Equalization for Continuous-Phase Modulations With Superimposed Pilot Sequences

Abstract: This paper proposes a new frequency-domain channel-estimation and equalization method for continuous-phase modulation (CPM) block transmissions with superimposed pilot signals. Our method provides spectral and power-efficient broadband CPM wireless communications with less complexity than previous methods. The proposed frequency-domain channel estimation uses the superimposed pilot sequence as a reference signal to reduce the throughput loss caused by traditionally multiplexed pilots. The proposed CPM frequency-domain decision feedback equalizer (DFE) eliminates the complexity overhead of conventional decomposition-based CPM receivers.

Millimeter-Wave and Terahertz Wireless RFIC and On-Chip Antenna Design: Tools and Layout Techniques

Abstract: This invited contribution provides insights for im- plementation of millimeter-wave and terahertz wireless systems on a chip (MTWSOC). We present an overview of important software and simulation tools and key layout issues and design rules for millimeter-wave (mmWave) circuits. An example of a recently fabricated 0.18µm CMOS integrated circuit by the Wireless Networking and Communications Group (WNCG) at The University of Texas at Austin is presented. The example chip includes 60 GHz on-chip antennas, an array of transmission lines, and IMPATT diodes. Index Terms—60 GHz, millimeter-wave, on-chip antenna, IM- PATT diode, CPW, Transmission Lines, RFIC, CMOS, WPAN, SOC, MTWS