The Orthogonal Frequency Division Multiplexing (OFDM) systems allow efficient spectrum usage and simple Frequency Domain Equalization (FDE). However, a large number of sub-carriers increases the computational complexity of the equalization process. In this paper, the conventional OFDM system is modified to enhance the Bit-Error-Rate (BER) performance or reduce the computational complexity. Also, the banded-matrix approximation is taken into account to reduce the equalization complexity. Simulation results show that the 1^st proposed OFDM system based on Binary Phase Shift Keying (BPSK) can reduce the computational complexity to O(N/2) instead of O(N) compared to the conventional OFDM configuration based on the banded-matrix approximation concept. The 2^nd proposed OFDM system based on BPSK requires approximately the same computational complexity of the conventional OFDM configuration and gives a Signal-to-Noise Ratio (SNR) gain of about 7.05 dB at BER = 10⁻³ compared to the corresponding conventional OFDM configuration. The 3^rd proposed OFDM system based on Quadrature Phase Shift Keying (QPSK) gives an SNR gain of about 4.51 dB at a BER = 10⁻³ compared to the corresponding conventional OFDM configuration. The 2^nd proposed OFDM system based on BPSK outperforms the different schemes in the presence of estimation errors.

正交频分复用（OFDM）系统可实现高效的频谱使用和简单的频域均衡（FDE）。然而，大量的子载波增加了均衡过程的计算复杂度。在本文中，对常规OFDM系统进行了修改，以提高误码率（BER）性能或降低计算复杂度。而且，考虑了带状矩阵近似以减小均衡复杂度。仿真结果表明，与基于带矩阵近似的传统OFDM配置相比，基于二进制相移键控（BPSK）的^第一种OFDM系统可以将计算复杂度降低到O（N / 2）而不是O（N）。概念。2^第二基于BPSK提议OFDM系统需要大约现有OFDM结构的相同的计算复杂性和给出了一个信噪比（SNR）大约在BER = 107.05分贝的增益^-3相比于相应的常规的OFDM配置。的3^次根据正交相移键控（QPSK）提议OFDM系统产生大约4.51分贝在BER = 10的SNR增益^-3相比于相应的常规的OFDM配置。的2^次基于BPSK提议OFDM系统优于在估计误差的存在下不同的方案。