Series in Microelectronics

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

Vol. 190

Christoph David Perels,
Frame-Based MIMO-OFDM Systems:
Impairment Estimation and Compensation
2008, 180 pages. € 64,00. ISBN 3-86628-172-2 AND 978-3-86628-172-1

Multi-antenna systems that use orthogonal frequency division multiplexing (MIMO-OFDM) are considered to be employed in future wireless local area networks (WLAN). When implementing such systems covering all aspects from analog signal conditioning to digital baseband processing, non-idealities appear that deviate considerably from idealized assumptions often found in literature.
Impairments such as carrier frequency offset, sampling rate offset, or channel attenuation must be estimated and compensated in order to allow successful communication at high data rates.
This thesis elaborates on impairments that dominate in frame-based WLAN MIMO-OFDM systems. Algorithms are reviewed and evaluated, keeping a feasible hardware implementation in mind. A generally suitable packet detection algorithm for any frame-based multi-antenna receiver is characterized and implemented. Multiple parameter estimation and compensation algorithms were implemented in a FPGA-based real-time MIMO-OFDM testbed. A preamble structure to allow efficient received signal power estimation is presented and used in the header of MIMO-OFDM frames.
All implemented algorithms where characterized with regard to complexity in a real-time FPGA-based testbed. Measurements characterizing the in-system performance were conducted. The impact on the system data throughput of individual algorithms shows that the loss incurred by the presence of such impairments can be mitigated at reasonable costs.

About the Author:
Christoph David Perels was born on April 15th 1972 in Heidelberg, Germany. He studied electrical engineering at the ETH Zurich from 1992 to 1997 and received his Diploma degree 1997. From 1997 to 2001 he worked at Swisscom Mobile in the field of mobile communications and mobile data services. In 2001 he joined the Integrated Systems Laboratory at ETH Zurich to work towards his PhD in the field of MIMO communication systems.

Keywords: MIMO-OFDM, WLAN, Synchronization, Parameter estimation, FPGA, Rapid prototyping, VLSI

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