Adaptive Frequency Symbol Spreading with Considering Link Correlation under Rician Fading Environment

Abstract

Recently, the demand for high-quality, high-capacity communications has been increasing, and the implementation of communication methods using high-frequency bands is being considered. Since the number of environments with Line-of-Sight (LoS) waves increases in high-frequency band communications, rician fading has attracted much attention. Orthogonal frequency-division multiplexing (OFDM) modulation is commonly used in modern wireless communications, and it is expected to be applied to rician fading environment. In OFDM, FSS has been proposed as a method to further improve communication performance. FSS spreads and superimposes the data symbols of each subcarrier on the frequency axis, and thus can reduce the effect of frequency selective fading. Although FSS can be applied in rician fading environment, the effect of FSS is expected to be small when the LoS is large compared to the multipath component. In this paper, we propose an adaptive FSS considering uplink and downlink correlation in frequency-division-duplex (FDD). From the simulation results, the proposed method can improve the BER performance while reducing the complexity of the system.