English

Abstract

The 3GPP long term evolution (3GPP-LTE) has adopted the Discrete Fourier Transform Spreading Orthogonal Frequency Division Multiple Access (DFTS-OFDMA) technique to be used in the uplink air interface for the next generation cellular systems. The DFTS-OFDMA is also a candidate of radio interface technologies for the IMT-Advanced standards in ITU-R. This technique has been adopted for uplink transmission due to its attractive feature of lower PAPR archived by precoding data symbols using a DFT operation at the transmitter. In this paper, we analyse the performance of DFT-Spreading OFDMA technique in PAPR reduction by using the IFDMA and LFDMA subcarriers mapping modes. We also analyse the performance of the DFTS OFDMA technique for PAPR reduction as the number of subcarriers allocated to each user varies, specifically with the LFDMA subcarriers mapping mode. Simulation results show that, the IFDMA improves PAPR performance significantly than LFDMA with pulse shaping and wihout pulse shaping but at a cost of increased bandwidth.Moreover, the performance of DFT-Spreading with LFDMA improves when the number of subcarriers allocated to users becomes small. Although, in-terms of PAPR power efficiency, the IFDMA performs better than LFDMA allocation scheme, but LFDMA is very superior in terms of throughput when channel dependent scheduling is utilized and has been widely implemented in LTE.