Integrated Circuits and Systems Group

Prof. Byunghoo Jung
Purdue University
Tuesday, June 22, 11:00am, ACES 3.408

Ultra Wideband Transceiver for Indoor Location-aware Applications

Motivated by the enormous success of outdoor location tracking systems, significant attention has focused on wireless indoor positioning systems for many promising location-aware applications such as emergency management, asset tracking, inventory management, home automation, health monitoring, and sensor networks. Various types of wireless indoor positioning systems have been developed mostly based on WLAN, Bluetooth or ZigBee networks.

Unfortunately the typical ranging accuracy of the WLAN and WPAN based systems (about 2-3m in optimal conditions) is not enough for many projected indoor location-aware applications. To mitigate the limited ranging accuracy issue, a few proprietary ranging systems based on IR-UWB have been investigated. Although the IR-UWB based ranging systems have demonstrated better accuracy than WLAN and WPAN based systems, the universal compatibility issue, which is important for wide deployment and robust operation, has not been properly addressed. To overcome the problems of non-standardized approaches, a new low-rate WPAN standard, 802.15.4a, aiming <30cm indoor ranging accuracy has been launched. We will present an implementation example of an integrated transceiver (RF front-end + baseband) that is fully compatible with the standard. The implemented transceiver achieves <18cm ranging accuracy and -79dBm sensitivity, the best ever reported, demonstrating the feasibility of reliable and standardized indoor location tracking. The issues in the transceiver architecture design and the approaches for improving the ranging distance and accuracy will be discussed.

Prof. Peter Kinget
Columbia University
Thursday, May 20, 3:00pm, ACES 5.336

Enhancing RF Receivers using Interference Cancellation and Digital Assistance

As IC technology feature sizes scale, the functional density of system-on-chip ICs increases and they often include multiple analog and RF interfaces. At the same time, nanoscale CMOS devices can only operate from lower supply voltages and can have poorer analog characteristics. This makes the design of analog and RF interfaces in nanoscale CMOS technologies particularly challenging.

In this talk we present our recent research in using digital gates to enhance the performance of RF circuits, more specifically of RF receivers. We review where digital gates can help to improve the RF performance. We discuss in detail two specific receiver circuits. The first example uses digital calibration to enhance the IIP2 performance of a direct conversion receiver for full duplex cellular systems. Thanks to digital calibration, the receiver design can be simplified while the performance can be drastically improved.

In the second example we will discuss the design of an ultra-low voltage direct-conversion receiver for cellular applications. So far the performance level of ULV receivers had been limited to wireless personal-area network applications due a degraded trade-off between the noise figure and the linearity caused by the supply voltage reduction. We show that this limit can be overcome by using an in-band feed-forward cancellation receiver architecture. It relies on digital calibration to achieve a robust, high performance across process and environmental variations.

Carl Anderson
IBM Fellow
Tuesday May 11, 8:00pm, ACES 2.402

Beyond Innovation – Dealing with the Risks and Complexity of Processor Design

The most important aspect of a successful design team is its culture and discipline. Innovation plays a part in the design of complex processor chips but does not determine if a project gets completed or is successful. Technical leaders not only need to innovate but manage resources and risk. This talk describes the discipline, risk management, resource management and problem identification and solving that needs to be in the culture of a successful design team.