Performance comparisons of localized and distributed transmissions using iterative decision-directed channel estimation in DFT-precoded OFDMA

Single-carrier (SC)-Frequency Division Multiple Access (FDMA) using discrete Fourier transform (DFT)-precoded orthogonal frequency division multiple access (OFDMA) achieves flexible orthogonal multi-access in the frequency domain while retaining a low peak-to-average power ratio (PAPR). Although the two types of transmission schemes are evaluated including localized and distributed transmissions, only the localized transmission is adopted in the shared channel carrying user traffic data in the Release 8 Long-Term Evolution (LTE). This paper proposes distributed transmission with affinity to resource block (RB) based resource assignment in order to gain the frequency diversity effect for DFT-precoded OFDMA in a frequency-selective fading channel. We apply iterative decision-directed channel estimation (DDCE) to the RB based distributed transmission to decrease the channel estimation (CE) error, which is a major impairment to distributed transmission. We present a comparison based on the average block error rate (BLER) performance levels between the RB based distributed and localized transmission schemes without and with intra-subframe frequency hopping (FH). Through extensive simulation evaluations, we show the effectiveness of the RB based distributed transmission associated with the iterative DDCE in decreasing the required average received SNR satisfying the target average BLER compared to the localized transmission.