Performance Analysis of OFDM with Different Modulation Schemes

Abstract: OFDM (Orthogonal Frequency Division Multiplexing) is a most frequently developing technology in modern mobile communication. OFDM is a parallel transmission scheme, where a high rate serial data stream is split up into a set of low – rate sub streams each of which is modulated on a separate subcarrier. Increasing the number of parallel transmission reduces the data rate that each individual carrier must convey and that lengthens the symbol period. However, in OFDM, no frequency diversity is exploited to improve BER performance. Today’s OFDM systems attempt to overcome this limitation by application of channel coding and interleaving, which requires a reduction in throughput. OFDM uses different type of modulation schemes to improve BER performance. In this paper we compared OFDM system by using 4-QAM, 16-QAM, 64-QAM and QPSK modulation schemes over multi-path fading channels at the cost of small increase in complexity.

Keywords: OFDM, BER, Parallel to Serial, Serial to Parallel Converter