DWT-MCM based OQAM modulation scheme in the downlink transmission of wireless systems

In this work, we proposed Offset-Quadrature Amplitude Modulation (OQAM) for Discrete Wavelet Transform (DWT) as alternative of Multi-Carrier Modulation (MCM) systems. Instead of the upsampler in the conventional DWT-MCM, OQAM is used in each level. In OQAM, each symbol will be separate into two components, in-phase and quadrature. With OQAM, maximum phase variation will decrease to its half value, which means that the performance of the RF power amplifier will improved. In addition, half symbols period will offset (stagger) the quadrature and in-phase components of the modulated signal to achieve low bit error rate. By contrast, in conventional orthogonal frequency division multiplexing (OFDM), without using the guard interval (Cyclic Prefix (CP)), inherent interferences cause degeneration in received symbols. In this paper, the proposed system model enhanced the spectrum efficiency and becomes more robust to the frequency selective environments. The simulation results illustrate that our proposed system model improves the system performance in terms of probability of errors compared with the OFDM system.