An Improved QPSK based on a Hybrid Genetic Algorithm for Efficient OFDM Transmission

Lowering the bit error rate (BER) and signal-to-noise ratio (SNR) in orthogonal frequency division multiplexing (OFDM) channels is computationally challenging due to internal weaknesses within modulation schemes. In this paper, the amplitudes of various data sets in the four quadrants of a quadrature phase shift keying (QPSK) signal are varied. Furthermore, a hybrid genetic algorithm (GA) is used for phase allocations during OFDM transmission. These enhancements are done so that the received data can be recovered by considering two different aspects, i.e., phase and its corresponding amplitude. The hybrid GA is created with two main enhancements. Firstly, the wind-driven optimization is used as its selection function, and secondly, a custom three-point crossover is used as its genetic recombination operator. When compared to the conventional QPSK and 64QAM, the enhanced modulation technique has less than 24%-BER in a Rayleigh channel whereas the conventional QPSK and 64QAM show results that spanned up to 40% and 29% BER respectively. The modified QPSK has an improved OFDM channel BER-SNR performance because there is great coherence between its transmitter and receiver.