Link adaptation algorithms for MIMO-based WiMAX systems

In order to extend the coverage of wireless communication to metropolitan scale, the Worldwide Interoperability for Microwave Access (WiMAX) standard was developed and ratified as the IEEE 802.16d standard in June 2004. The standard defines an adaptive modulation framework which allows a WiMAX system to communicate with various burst profiles according to the link quality. The selection mechanism of a suitable burst profile is left open for research. This thesis devises a link adaptation algorithm for the MIMO-based WiMAX systems. Cross layer design approach which combines both the signaling level simulation in the PHY layer and the protocol level simulation in the MAC layer are adopted. A MIMO simulation framework in which the PHY layer metrics can be passed into the MAC layer under practical simulation environment is also constructed using existing well-known simulation tools. Extensive simulation experiments will demonstrate that the proposed algorithm could achieve high system throughput while keeping the packet error rate low