High data rate applications are driving the need for high throughput and spectrally efficient broadband communication systems. Efficient modulation schemes and multiple antenna techniques are being explored for such applications. MIMO-OFDM is one such promising technology. OFDM modulation has been adopted by almost all the major broadband wireless standards such as, 802.11a/g, DVB-T/DVB-H, 802.16, UWB, etc. MIMO-OFDM is also finding its way into some of the newer standards such as 802.11n and 802.16e. The key aspects of all of these standards are reliability and high-throughput. Mobility is also a key factor in some of these standards.
In this tutorial we will start off by discussing the wireless propagation environment and study the characteristics of the wireless environment in the presence of scattering and mobility. We will introduce the audience to the key concepts of OFDM and MIMO-OFDM systems, relating aspects of information theory that led to the development of MIMO-OFDM systems. We will then consider the practical issues related to OFDM system and receiver algorithms, including the impact of RF and analog impairments on OFDM and MIMO-OFDM systems. The 802.16/802.16e physical layer will be discussed and will be used to exemplify the various aspects of OFDM and MIMO-OFDM technology.
In addition we will discuss some architectural aspects of FPGAs that make them a popular choice for developing wireless communication systems at the basestation, given their configurability and time to market advantages. Newer generation FPGAs also have dedicated fabric for efficient implementation of DSP and communication systems. Newer, higher level design methodologies, further improve this time to market advantage of FPGAs. We will briefly discuss these methodologies and also introduce some of the DSP and communication centric features of popular FPGAs.
Dr. Raghu M. Rao
Dr. Raghu Rao is a Senior Staff communications Systems Engineer in the Advanced Systems Technology Group at Xilinx Inc. He has a PhD in wireless communications from UCLA where his thesis topic was Performance Analysis of MIMO-OFDM Systems. Prior to joining Xilinx Raghu worked for Texas Instruments, Logic Modeling Corporation and was the Director of Engineering at Exemplar Logic. Most recently Raghu was the VP of engineering for a communications start-up developing MIMO-OFDM and DVB-H technologies. From 1999-2004 he was a fulltime PhD candidate researching algorithms for MIMO-OFDM wireless communication systems. From 1989-1992 he was at Texas Instruments (India) Pvt. Ltd. where he worked on placement and routing algorithms for ASICs and FPGAs. Between 1992 and 1994 he was involved in developing software for hardware modelers at Logic Modeling Corp. From 1994-1999 he was at Exemplar Logic Inc. where he worked on timing analysis and timing optimization algorithms for FPGA designs and later on was Director of Engineering where he was responsible for all of Exemplar Logic’s engineering activities. His interests are in digital communication algorithms, signal processing and efficient DSP and communication algorithms for FPGAs.
Dr. Chris H. Dick
Dr. Chris Dick is the DSP Chief Scientist at Xilinx. Chris has worked with signal processing technology for two decades and his work has spanned the commercial, military and academic sectors. Prior to joining Xilinx in 1997 he was a professor at La Trobe University, Melbourne Australia for 13 years and managed a DSP Consultancy called Signal Processing Solutions. He has been an invited speaker at many international signal processing symposiums and workshops and has authored more than 70 journal and conference publications, including many papers in the fields of parallel computing, inverse synthetic aperture radar (ISAR), FPGA implementation of wireless communication system PHYs and the use of FPGA custom computing. Chris' work and research interests are in the areas of fast algorithms for signal processing, digital communication, software defined radios, VLSI architectures for DSP, adaptive signal processing, synchronization, hardware architectures for real-time signal processing, and the use of Field Programmable Arrays (FPGAs) for custom computing machines and real-time signal processing. He holds a bachelor’s and PhD degrees in the areas of computer science and electronic engineering.