Constant Envelope DCT based OFDM System with M-ary PAM Mapper over Fading Channels

摘要

Constant Envelope Discrete Cosine Transform based Orthogonal Frequency Division Multiplexing (CE-DCT-OFDM) system with M-ary Pulse Amplitude Modulation (PAM) mapper is considered. In the system phase modulation is used to achieve constant envelope signals that have 0 dB Peak-to-Average-Power Ratio (PAPR). Transmission of such signals permit high power amplifiers in the system to operate with maximum power efficiency. The performance of CE-DCT-OFDM system is examined over Additive White Gaussian Noise (AWGN) and over fading channels. Closed-form expressions for Bit Error Rate (BER) over Ricean and Rayleigh channels are derived. The performances of CE-DCTOFDM and conventional DCT-OFDM systems are compared as a function of Input power Back-Off (IBO) and Signal-to-Noise Ratio (SNR) for the Traveling-Wave Tube Amplifier (TWTA) model. Results show that CE-DCT-OFDM system offers superior BER performance compared to DCT-OFDM system and has other advantages as well.