Peak to Average Power Ratio Reduction for Filtered OFDM Modula-tion in 5G Frameworks Using Hybrid Techniques

Abstract

Filtered Orthognal Frequency Division Multiplexing (FOFDM) is the upcoming modulation structure for 5G communication framework with higher spectral efficiency as it has lower side-lobes. However, in all multicarrier modulations, it aches from abnormal peaktoaverage power ratio (PAPR) thatshakes the power amplifiers linearitywhichclues in connection with signal distortion and spectral regrowth with abnormal Bit error rate. In the system, it lowers power efficiency and poor battery life is due to high PAPR, which encumbers in the implementation of Multicarrier modulation.In the literature a more number of single techniques for peak to average power reduction were engaged but results in relatively low reduction, also it has some failingsthat may influence the presentation of framework boundaries like Bit Error Rate and spectral efficiency. Therefore, a combined technique is presented, i.e. precoding with companding for more reduction in the PAPR to maintain the overall system performance in the 5g networks.The precoding method spreads the energy f data symbol over the subcarriers which minimized the autocorrelation coefficients of IFFT input that lessen the PAPR of OFDM signal into the single carrier level transmission.The statistical characteristics level of the multicarrier outcome signals by the Rayleigh distribution into uniform distribution which results in peak and normal power levels of OFDM signal due to the companding process and consequently reduces the PAPR.The proposed techniques combine the precoding techniques: Walsh Hadamard Transform (WHT) and Discrete Hartley Transform (DHT) with two novel non-linear companding techniques: Absolute Exponential Companding (AEC) and Rooting Companding Technique (RCT). We have examined, compared, and analyzed the peak average power ratio for filtered OFDM using both conventional single and hybrid techniques. The companding techniques have shown a higher reduction in PAPR when compared with the precoding techniques. The hybrid Discrete Hartley Transform with Root Companding Technique has shown the least PAPR of 4.7dB and the highest reduction performance in all used techniques with a reduction of about 6.1 less thanReal FOFDM peaktoaverage power ratio. From the outcomes, the hybrid procedures have indicated a superior execution by adequately diminishing the peak to average power proportion without corrupting the presentation of framework when contrasted and the traditional single techniques.