On OFDM and single-carrier frequency-domain systems based on trigonometric transforms

Orthogonal-frequency-division-multiplex (OFDM) and single-carrier (SC) frequency domain structures are simple equalization schemes that make use of the discrete Fourier transform (DFT) diagonalization properties. This letter approaches these problems within a well-known matrix algebra that allows for straightforward extensions of recent results on real trigonometric transforms, namely, the discrete cosine (DCT), sine (DST), as well as new Hartley transform (DHT) schemes. They are especially useful for real modulations and can outperform the corresponding DFT-based schemes when the channel memory is smaller than the introduced redundancy. We further look into efficient DHT schemes yielding the same throughput as the DFT counterparts and provide simulations assuming perfect channel state information (CSI)