Multirate 5G Downlink Performance Comparison for f-OFDM and w-OFDM Schemes with Different Numerologies

Abstract

One of the main open problems for next generation wireless networks, is to find the new OFDM-based waveform to be used in 5G. The new modulation scheme must primarily be able to achieve higher spectral efficiency than its predecessor. The main 3GPP's candidate is a new version of OFDM, called Filtered Orthogonal Frequency-Division Multiplexing (f-OFDM), which is similar to OFDM but with additional filtering in order to reduce Out-Of-Band (OOB) emissions and to obtain a better spectral-localization. Another option is windowed-OFDM (w-OFDM), which is basically a classical OFDM scheme where each symbol is windowed and overlapped in the time domain. In this paper we compare classic OFDM signals using Cyclic Prefix (CP-OFDM) with f-OFDM and w-OFDM, each one with multiple parametric options and numerologies. A multirate transmitter simultaneously operating with multiple numerologies is considered, where the transmitted sub-bands must be up-sampled and interpolated in order to generate the composite numerical signal fed to the Digital to Analog Converter (DAC). Finally, we discuss advantages and disadvantages of the various schemes.

5G UFMC Scheme Performance with Different Numerologies

“…Simulation results clearly show that the BER performance of the UFMC modulation scheme is increased when the FFT size increases, as it is seen from the comparison of Figures 4-7. BER values are comparable to the ones found in the literature [12].…”

“…Different filters per subband can be designed. For example, many researchers [12] use windowed-sinc filters with Blackman windowing Functions, while other researchers [13] use Zero Padding Length Design filter techniques.…”

Proposta de uma Função de Janela com Parâmetros Ajustáveis Baseada nos Polinômios de Jacobi com Aplicação no Sistema f-OFDM

“…para −L/2 ≤ l ≤ L/2, onde L é a ordem do filtro, R denota o excesso de largura de banda e N i f f t é a ordem da IFFT [14]. Logo, o sinal f-OFDM ( s(t)) é obtido aplicando o filtro normalizado h(l) no sinal OFDM (descrito por (3)) em cada sub-banda, da seguinte maneira:…”

UFMC and f-OFDM: Contender Waveforms of 5G Wireless Communication System

“…Different studies were conducted to find an alternative waveform that have the ability of solving OFDM disadvantages and could be introducing as contender candidate for 5G wireless communication systems. Hence, Filtered-OFDM (f-OFDM) has been suggested as candidate solution to meet 5G requirements, it could provide great flexibility better than conventional CP-OFDM [6], [8]- [12]. It is similar to OFDM system with one difference is the use of filtering to minimize OOBE and achieve better spectral localization [8].…”

“…Hence, Filtered-OFDM (f-OFDM) has been suggested as candidate solution to meet 5G requirements, it could provide great flexibility better than conventional CP-OFDM [6], [8]- [12]. It is similar to OFDM system with one difference is the use of filtering to minimize OOBE and achieve better spectral localization [8]. In other hand, the performance of OFDM and f-OFDM have been analyzed in Machine Type Communications (MTC).…”