LTE multi-antenna techniques based on Alamouti SFBC with correlated channels

In this paper, we will introduce Alamouti SFBC multi-antenna capabilities of Long Term Evolution´s downlink channel. Alamouti´s simple algorithm will be generalized by using four transmit antennas based on a combination of SFBC and Frequency Shift Transmit Diversity FSTD, and by using MIMO 2×2 transmission scheme. To prove the efficiency of these techniques, we will consider spatial correlation between multiple antennas and frequency correlation between OFDM subcarriers. We will also present a theoretical demonstration of the correlations expressions. Our simulations results will confirm the performance degradation caused by the spatial and frequency correlation, and the strength of Alamouti SFBC against the spatial correlation. The paper demonstrate the advantage offered by using FSTD technique to combat frequency correlation.