Investigation on transmit and receiver diversity gains considering channel estimation error for uplink DFT-precoded OFDMA

Transmit diversity associated with receiver diversity is very effective in improving the bit error rate or block error rate (BLER) performance as a Rank-1 transmission scheme. However, it is not easy to rely on theoretical analysis to analyze transmit and receiver diversity gains considering channel coding, frequency diversity through a wider transmission bandwidth, and channel estimation error in Discrete Fourier Transform (DFT)-precoded Orthogonal Frequency Division Multiple Access (OFDMA) using a frequency domain equalizer (FDE). Therefore, this paper investigates the gains of transmit diversity and receiver diversity considering channel estimation error for uplink DFT-precoded OFDMA. More specifically, we clarify the gains from open-loop (OL) transmit diversity using space-time block code (STBC) based coding and closed-loop (CL) transmit diversity with codebook based precoding at a set of user equipment (UE) assuming receiver diversity with the maximum of 12 antennas at a base station (BS) based on link-level computer simulations. Then, we clarify the numbers of transmit and receiver diversity branches, which provide distinct gains in terms of the BLER improvement.