Series in Microelectronics

edited by        Wolfgang Fichtner
                        Qiuting Huang
                        Heinz Jäckel
                        Gerhard Tröster
                        Bernd Witzigmann

Vol. 192

Simon Häne,
VLSI Circuits for MIMO-OFDM Physical Layer.
2007, 170 pages. € 64,00. ISBN 3-86628-196-X AND 978-3-86628-196-7

Abstract:
Data rates provided by wireless communication systems have been growing exponentially in time. Today, about a decade after the first publications on multiple-input multiple-output (MIMO) wireless systems, the adoption of multiple antennas at both ends of the wireless link in practical systems is considered the most promising technique for breaking the gigabit-per-second barrier. In fact, MIMO provides a linear increase in channel capacity with the minimum number of transmit or receive antennas at the cost of increased receiver complexity only, without additional bandwidth or transmit power expenditure.

When combined with broadband modulation schemes such as orthogonal frequency division multiplexing (OFDM), MIMO receivers pose signal processing requirements that call for dedicated very-large scale integration (VLSI) circuits. Even on state-of-the-art process technologies, however, the realization of optimal MIMO algorithms is impossible, so that suboptimal solutions must be adopted.

This thesis focuses on the joint design of reduced-complexity algorithms and corresponding VLSI architectures for some of the most implementation-critical signal processing tasks in MIMO-OFDM systems, including channel estimation, soft-information extraction, and Viterbi decoding. Appropriate algorithm modifications avoid operations that are ill-suited for VLSI implementation and reduce the overall operation count to a manageable order of magnitude. The proposed circuits are prototyped in a real-time testbed for proof of concept and provide reference figures for the silicon complexity of broadband MIMO systems. Insight into performance and limitations of real-world MIMO systems is provided by extensive measurements based on a multipath channel emulator.

About the Author:
Simon Häne
was born in Switzerland in 1978. He received the Dipl. Ing. degree in 2002 from the ETH, Zürich, Switzerland. He joined the Integrated Systems Laboratory at the ETH as a research assistant, working on the development of integrated circuits for signal processing in MIMO wireless communication systems.

Keywords: MIMO-OFDM, WLAN, Channel estimation, Soft-information extraction, Viterbi decoding, FPGA, Rapid prototyping, VLSI

Series in Microelectronics

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