Signal Detection Improvement Using Bottom Up Wavelet Algorithm in QAM Modulation Reception

Quadrature amplitude modulation (QAM) is one the common modulation used in digital communications. The major problem of communication systems in transferring data is the additive channel noise which corrupts the underlying curve. Until now, techniques that have been applied to mitigate this problem, such as using parity bit, ..., are mainly intended for implementation at the transmitter end and before the signal is modulated. Obviously had no effect on signal noise in receiver. In this paper, a new block is inserted in the receiving path for alleviating this problem. The block acts as a decision maker that would present a pure signal at the input of the A/D stage. The performance of the introduced block is based on the method of second generation wavelet. The most important part in this method is the proper choice of an appropriate base function, designed according to the input signal, it means not use of single wavelet. Specific wavelets are designed for each noisy signal to achieve the best adaption with data in every scale and location.