Joint optimization of bit loading and modulation classification in wireless OFDM systems

This paper presents a novel adaptive transmission technique for time-division duplex (TDD)-based wireless orthogonal frequency division multiplexing (OFDM) systems which jointly optimizes the bit loading algorithm at the transmitter side and the modulation classification method at the receiver side. Instead of signaling the complete bit allocation table (BAT) to the receiver, a novel maximum-a-posteriori (MAP) modulation classification algorithm is applied to increase the effective data rate. Constraints on the bit loading algorithm aid to significantly increase the classification reliability while maintaining a high link quality and a low signaling overhead. Simulation results in terms of the classification reliability and the effective bandwidth efficiency reveal the superior performance of the proposed adaptive scheme for the transmission of short bursts in a typical indoor propagation scenario.