Enhanced universal filtered-DFTs-OFDM for long-delay multi-path environment

Yuji Mizutani, Hiroto Kuriki, Yosuke Kodama, Keiichi Mizutani, Takeshi Matsumura, Hiroshi Harada

Abstract: In this paper, an enhanced universal filtered (UF)-DFT-spread-OFDM (eUF-DFTs-OFDM) is proposed. The conventional UF-DFTs-OFDM can drastically reduce the out-of-band emission (OOBE), which has been the problem of the conventional cyclic prefix (CP)-DFTs-OFDM. However, the conventional UF-DFTs-OFDM degrades the communication quality in long-delay multipath environment due to the frequency-domain ripples derived from extending the rise and fall time of the LPF corresponding to the guard interval (GI). On the contrary, the proposed eUF-DFTs-OFDM achieves significantly low OOBE and high communication quality even in the long-delay multi-path fading environment by applying the CP and the LPF with short rise and fall time. The advantages of the proposed eUF-DFTs-OFDM are discussed by simulating the characteristics of the OOBE, peak-to-average power ratio (PAPR) and block error rate (BLER) with the LTE uplink parameters. As a result, it is confirmed that the proposed eUF-DFTs-OFDM is capable of suppressing the OOBE at the channel edge by 40 dB compared to the conventional CP-DFTs-OFDM. Moreover, the proposed eUF-DFTs-OFDM can improve the ES/N0 to achieve BLER= 10-3 by about 2 dB for QPSK and 16QAM compared to the conventional UF-DFTs-OFDM. Especially for 64QAM, the proposed eUF-DFTs-OFDM can achieve BLER = 10-3 at an ES/N0 of 30 dB, even though BLER characteristics of the conventional UF-DFTs-OFDM results in error floor.