Performance of adaptive learning schemes for adaptive modulation

Adaptive modulation has emerged as a prime technique in wireless systems to improve system capacity and spectral efficiency. Its basic idea is to adapt the modulation scheme to the fading channel quality, using different schemes for different channel conditions. Therefore, a primary issue is to determine the thresholds for switching between the modulation schemes. Typically, these thresholds are fixed. Recently, a novel adaptive learning approach capable of dynamically adjusting the thresholds to maximize a performance criterion, for example the data throughput, was introduced (see Tang, C., 2001 Int. Conf. on Third Generation Wireless and Beyond, p.30-5, 2001; IEEE 54th Vehicular Technology Conf., vol.1, p.144-8, 2001). The paper presents further simulation results for this new method.