Modulation level detection scheme for sub-band adaptive OFDM system

Sub-band adaptive OFDM is a modulation technique in which the OFDM transmitter adapts a different modulation level according to channel conditions. In order to successfully demodulate the transmit data symbols, the receiver has to have reliable prior knowledge to the modulation level. This information can either be conveyed as a signaling symbol or the receiver can attempt to estimate the parameters employed at the transmitter by means of blind detection mechanism. This paper proposes a novel modulation level detection scheme which uses the adaptively modulated data symbols. Blind modulation level estimation scheme is coupled with MAP decoding process in order to improve the detection performance.