BPSK OFDM Modulation Bit Error Rate Analysis in OFDM Systems

OFDM is a Frequency Division Multiplexing (FDM) scheme used as a digital multi-carrier modulation method. It employs a large number of densely spaced orthogonal subcarrier signals to carry data through multiple parallel data streams or channels. Each subcarrier is modulated using conventional modulation schemes such as Quadrature Amplitude Modulation or Phase Shift Keying at low symbol rates, while maintaining a total data rate comparable to conventional single-carrier modulation schemes within the same bandwidth. In OFDM systems, BPSK modulation demonstrates relatively low bit error rates. Therefore, I frequently perform bit error rate simulations using OFDM modulation. This article presents simple OFDM transmitter and receiver implementations for both AWGN and Rayleigh channels. The implementation includes establishing the relationship between Eb/No (bit energy to noise power spectral density ratio) and Es/No (symbol energy to noise power spectral density ratio), with detailed calculation of bit error rates when using BPSK modulation. Key implementation aspects involve IFFT/FFT operations for orthogonal subcarrier generation, cyclic prefix insertion for mitigating inter-symbol interference, and maximum likelihood detection for signal demodulation.