A study of adaptive modulation technique in OFDM

This paper presents the results of a study of the OFDM adaptive modulation technique. The adaptive modulation technique, which selects the modulation scheme according to the transmission conditions, is effective in improving system throughput. Then, it is important to study evaluation function under various propagation conditions. In this paper, we propose an adaptive modulation technique using the instantaneous DUR (desired signal to undesired signal ratio) per packet as the performance measure of the transmission path, in which the intersymbol interference (ISI) and intercarrier interference (ICI) power of delayed waves exceeding the guard interval are used under the assumption of convolution coding and soft-decision Viterbi decoding. A DUR estimation method is also proposed. The effectiveness of the approach is confirmed by numerical simulation. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(3): 36–45, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20254