Dipl.-Ing. Christian P. Hoymann
Prof. Dr.-Ing. B. Walke
RWTH Aachen University
Chair of Communication Networks (ComNets)
christian.hoymann@comnets.rwth-aachen.de
Introduction
Nowadays many researchers, manufacturers and operators are looking at WiMAX. WiMAX networks are foreseen to provide broadband wireless access to mobile users everywhere at lowest costs. But what is WiMAX? This tutorial gives a detailed introduction to the technology, it provides valuable performance evaluations and finally it reports about current activities and future developments. Having attended this tutorial the audience gained insights into the WiMAX system, its capability and future trends. One is able to evaluate what such systems can do and what they cannot.
Tutorial Outline
Chapter one gives an introduction to the WiMAX system. The WiMAX Forum comprises the metropolitan area network standards IEEE 802.16 as well as ETSI/BRAN HiperMAN. Different standardization groups, target frequencies and deployment concepts are outlined.
Based on the reference model the following two chapters elaborate on the IEEE 802.16 protocol stack comprising the medium access control (MAC) and the OFDM-based physical (PHY) layer. Chapter two illustrates the MAC frame structure and describes the basic control elements. Further QoS management in IEEE 802.16 is presented. Likewise, chapter three outlines the basic physical layer modules of an IEEE 802.16 OFDM transmitter-receiver chain.
An example scenario that allows to evaluate important influences of the protocol is derived in chapter four. The example scenario is used in the following chapter five that evaluates the system performance. The first subchapter calculates the physical layer as well as the MAC layer capacity by means of a mathematical analysis. Different protocol features such as packing / fragmentation are evaluated. Several MAC layer configurations are analyzed in the context of throughput and overhead. The trade off between robustness and high capacity is shown. After the introduction of the simulation tool developed at ComNets in the second subchapter, characteristic performance and system measures are given based on stochastic event-driven computer simulations.
Finally, the application of enhanced modes of operation is presented. The mobility support of the current IEEE 802.16e draft is presented. This standard amendment extends the protocol with handover functionality and inter base station communication. The optional MESH mode overcomes the mandatory point-to-multipoint deployment concept and allows for multi-hop communication. The adaptive antenna system (AAS) option reserves portions of the MAC frame to AAS-enabled stations communicating with advanced technologies such as space time coding and MIMO. In the end, different concepts to allow for space division multiple access in IEEE 802.16 networks are presented.
Summary
1. Introduction to WiMAX systems
2. Medium Access Control Layer
a. MAC Frame Structure
b. MAC Management Functions
c. MAC Quality of Service
3. Physical Layer (OFDM)
4. Simulation Environment
5. Performance Evaluation
a. Analytical Results
b. Simulation Results
6. Enhanced Modes of Operation
a. Mobility Support in 802.16e
b. Relay-based (Mesh) Deployments
c. Advanced Antenna Systems (AAS)
d. Space Division Multiple Access (SDMA)
Biography Christian P. Hoymann
Christian P. Hoymann received his Diploma degree in electrical engineering from RWTH Aachen University in 2002. During his studies he worked with the Multimedia & Video Technology research group at SIEMENS Corporate Research, Princeton, N.J., USA. Since 2002 he is employed as a Research Assistant for the Chair of Communication Networks (ComNets) of RWTH Aachen University where he is working towards his Ph.D. degree.
He worked in the fields of traffic engineering and dimensioning of GSM/GPRS networks together with his project partners at D2 Vodafone. He was actively involved in the IST-STRIKE project where smart antenna systems had been integrated in Metropolitan Area Networks. His current research interests include the optimization of MANs especially in consideration of smart antenna technologies such as SDMA and relaying concepts such as Mesh.
Mr. Hoymann conducted a successful GSM/GPRS tutorial at several international conferences and companies. He has published several papers and was actively involved in the standardization of SDMA technologies for IEEE 802.16.
Biography Bernhard H. Walke
Bernhard H. Walke is an internationally recognized expert (numerous publications, including several internationally published books) in the field of communication networks. His group's research work focuses on formal specification, modeling, mathematical and simulative analysis, and pilot implementation of protocols and services for communication networks.
Having worked at AEG-TELEFUNKEN Research Institute, and later at Fern University of Hagen (Chair for Data Processing Techniques), he has held the chair of Communication Networks at Aachen University since 1990. He is member of various national and international expert groups and coordination boards (e.g., ITG, AG Mobikom, WWRF) and has frequently served as an advisor to the German national regulation body (RegTP).