At the receiver of the proposed system, the clipped OFDM signal with normalization after transmission over the AWGN channel can be expressed as
Thus, the theoretical BER formula of the clipped and normalized M-QAM OFDM can be expressed from [33]:
When G = 1, Equation (20) becomes the SNR of the conventional clipped OFDM, and it can be expressed as
Based on Equation (15), the signal-to-noise-and-distortion ratio (SNDR) of the kth subcarrier for the clipped and normalized OFDM system is given by
The overall performance of the clipped and normalized system can be expressed as
When G = 1 in Equation (25), the clipped and normalized OFDM system is converted into the conventional clipped OFDM system.
Therefore, the BER of every subcarrier of the clipped system without normalization can be expressed as
The overall performance of the clipped OFDM system can be expressed as
The BER of the simulation and measured results in the following section show that the BER performance of the clipped and normalized OFDM signal can be greatly improved compared with the conventional clipped OFDM and conventional OFDM signals.
Therefore, the clipped and normalized OFDM system can obtain the best BER performance over the AWGN channel at clipping ratio (CR) of 4.
Theoretical and Experimental Investigation of Direct Detection Optical OFDM Systems with Clipping and Normalization
At the last light interception measurement at 97 DAP, treatments in narrow rows not clipped at R4 intercepted 95% of PAR compared with 78% in wide rows, while treatments in narrow rows clipped at R4 intercepted 82% of PAR compared with 55% in wide rows.
Furthermore, soybean clipped at all three growth stages yielded 7, 26, and 11% greater than soybean clipped at R4, V5 + R4, and R1 + R4.
Soybean Light Interception and Yield Response to Row Spacing and Biomass Removal