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Introduction to Rayleigh Fading and Rician Fading
In different real-life scenarios, electromagnetic wave transmission encounters various obstacles. For instance, the results differ significantly between an open field and a city crowded with skyscrapers. When no obstructions exist, electromagnetic waves can travel directly from the transmitter to the receiver. However, when obstacles are present, phenomena such as reflection, absorption, and diffraction occur. Therefore, to better simulate wave propagation in different environments, various channel models have been developed. This article introduces the two most classic models: the Rayleigh Fading Channel and the Rician Fading Channel. Before diving into those, we must first review IQ Modulation.
IQ Modulation
In articles discussing up-conversion and down-conversion, IQ modulation is often mentioned briefly. Simply put, before a baseband signal is sent by the transmitting antenna, the system performs modulation. This technique shifts the baseband signal to a high frequency so the antenna can transmit a high-frequency signal. Upon receiving this signal, the receiving antenna performs demodulation to restore the original baseband signal.
Even if this sounds unfamiliar, the key point is that modulation involves multiplying the signal by a high-frequency sine wave called a carrier wave. For example, a…
