PAPR Analysis of DHT-Precoded OFDM System for M-QAM

High Peak to Average Power Ratio (PAPR) is one of
the major drawbacks in Orthogonal Frequency Division
Multiplexing (OFDM). The High PAPR increases the
complexity of Analogue to Digital (A/D) and Digital to
Analogue (D/A) convertors and also reduces the efficiency of
RF High Power Amplifier (HPA). In this paper we present an
analysis of Discrete Hartley Transform (DHT) precoded
OFDM system using M-QAM (where M=16, 32, 64, 256). We
compare the computer simulation results of DHT precoded
OFDM system with DFT precoded OFDM system, Walsh
Hadamard Transform (WHT) precoded OFDM system,
Selected Mapping (SLM) based OFDM system and OFDM
conventional. Simulation results show that the PAPR of DHT
precoded OFDM system is lower than WHT precoded OFDM
system, SLM-OFDM system and OFDM conventional. We also
concluded in this paper that DFT precoded OFDM system has
zero PAPR.