Investigations of computational complexity and ber analysis of multicarrier waveforms

Abstract

The exponential growth of mobile devices and increasing requirements of users have necessitated going beyond Fourth-Generation (4G) mobile communications. The Fifth Generation (5G) and beyond 5G wireless technologies aim to improve the data rate, reliability, power efficiency, connectivity, and latency to achieve such growth. The 5G physical layer needs an effective modulation and waveforms to meet the demands of 5G new radio. The International Mobile Telecommunication (IMT) 2020 defines the three main agendas. They are enhanced mobile broadband (eMBB), Ultra-Reliable Low Latency Communications (URLLC), and Massive Machine-Type Communications (MMTC). Flexibility is strongly required for accepting such system scenarios. newlineMulticarrier waveform enables simultaneous transmission of a set of data over multiple subcarriers. One such multicarrier modulation is fixed subcarrier mapping Orthogonal Frequency Division Multiplexing (OFDM) has been used in Fourth Generation-Long Term Evolution (4G-LTE). However, OFDM has large out of band emission and high Peak to Average Power Ratio (PAPR), and high complexity. So, the current OFDM technology will not be sufficient to meet such requirements. The third Generation Partnership Project (3GPP) proposed a new set of 5G radio waveforms. One of the new waveforms is Resource Block Filtered Orthogonal Frequency Division Multiplexing (RB-F-OFDM), which combines the benefits of Filtered Orthogonal Frequency Division Multiplexing (F-OFDM) and Filter Bank Multicarrier (FBMC). RB-F-OFDM is scalable and modular but it has high complexity and fixed guard band allocation. Hence it does not support all categories defined by IMT-2020. newlineThis work presents an effective RB-F-OFDM which incorporates a novel Fast Walsh Hadamard Fourier Transform (FWFT) subcarrier mapping method to reduce the computational complexity and PAPR. Further reducing the PAPR value Partial Transmit Sequence (PTS) is proposed along with an adaptive filter method to reduce the sidelobes of the transmitted signal. Proper subcarrier mapping and phase adjustment can reduce PAPR as well as Bit Error Rate (BER) of multicarrier modulation schemes. In FWFT the arithmetic operations and indexing delays are lower than the Fast Fourier Transform (FFT) operations. More than half of the elements in each stage of FWFT are zero and the number of samples is present only at the diagonal of the matrix. Then the sum rate of all the transmitted signals has the peak value is decreased and the BER of all the signals received at the receiver is reduced. The proposed RB-F-OFDM system has reduced the PAPR to a significant value of around 5.8dB. newline newline