Performance of Adaptive Modulation Techniques for Wireless Local Area Networks

摘要

The Orthogonal Frequency Division Multiplexing (OFDM) technique has been used in Wireless Local Area Networks (WLANs) for combating the multipath distortion. The severe intersymbol interference (ISI) which results from the multipath distortion can be mitigated by simple scalar division operation when OFDM is used. However, in addition to the ISI mitigation capability, the use of OFDM enables us to adaptively load the various subcarriers used for communication. Adaptive loading can be done to optimize various system parameters which can result in benefits compared to uniform loading. We present the performance of adaptive loading schemes for WLANs based on the IEEE 802.11a standard. Simulation results illustrate the performance advantages of adaptive loading techniques in such systems.