Tap Loading of Subcarrier Equalizers for Wireless Multicarrier Transceivers

We present a novel algorithm for defining the lengths of subcarrier equalizers employed by wireless multicarrier transmission systems operating in frequency-selective fading channels. The equalizer lengths across the subcarriers are incrementally varied in a ldquogreedyrdquo fashion until the global cost function is below some prescribed threshold. By varying the equalizer lengths, the overall complexity of the equalization is constrained while the system meets a minimum error performance. Moreover, we investigate four strategies for terminating the proposed algorithm when an adequate number of equalizer taps have been allocated in this process. The results show that a system that employs variable-length equalizers defined by the proposed algorithm can achieve an improvement in error robustness of as much as an order of magnitude, relative to a system that employs constant length equalizers with the same overall complexity.