Abstract The paper examines the decorrelation gain achievable for M-ary Quadrature Amplitude Modulation (M-QAM) and Binary Phase-shift Keying (BPSK) schemes in spatial diversity configurations, where virtually synthesized signals are applied over Nakagami-m fading channels. The signals are embedded in additive white Gaussian noise (AWGN). The primary form of the suggested virtual signal synthesizer involves shifting the phase of the generated output signals. To obtain the decorrelation gain, an orthogonal transformation matrix is utilized. This matrix ensures energy preservation, is blind to channel correlation, and does not require explicit signal information. The aim is to generate virtual signal that would be equivalent to those received from a system with more antennas. An analytical framework is developed to assess how fading severity, diversity order, and branch correlation influence Symbol Error Rate (SER) characteristics. Monte-Carlo simulations validate the analytical results. Various antenna configurations and fading severities ( m = 0.5, 1, 3, 5) are explored. Additionally, the impact of different antenna spacings (0.1, 0.2, 0.5 wavelengths) is analyzed under a uniform angle of arrival. The results indicate that decorrelation gains are obtained, with a moderate dependence on the fading severity parameter m . However, this dependence becomes negligible for higher values of m .
Omosa et al. (2026) studied this question.