MAC Layer Concepts to Support Space Division Multiple Access in OFDM based IEEE 802.16

Advanced antenna technologies and algorithms have been developed during the last years. But until today, advanced antenna algorithms in the physical layer and the modes of operation in medium access layers have not been integrated in modern wireless systems. As one of the first standards the metropolitan area network IEEE 802.16 provides means to support smart antenna techniques.After a detailed introduction of the medium access control layer this article outlines the support of space division multiple access (SDMA) techniques by the wireless metropolitan area network IEEE 802.16. New concepts are introduced that allow and further optimize the use of SDMA techniques brought by intelligent antennas. First, the possibility to enable SDMA in the IEEE 802.16a-2003 protocol is investigated, and second the support of SDMA in the revised 802.16-2004 standard is elaborated in detail. To overcome current limitations of 802.16a-2003, an enhanced control structure is introduced in 802.16-2004 that masters a concurrent transmission and reception of data to/from several different subscriber stations. The approach facilitates a fully flexible structure which significantly improves system capacity. Christian P. Hoymann received his Diploma degree in electrical engineering from RWTH Aachen University in 2002. Before he served a student internship at SIEMENS Corporate Research, Princeton, USA. Since 2002 he is employed as a Research Assistant at 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 technologies such as Mesh.Mr. Hoymann has published several conference and journal papers and was actively involved in the standardization of SDMA technologies for IEEE 802.16.