On the use of Zero Padding with discrete cosine transform Type-II in multicarrier communications

In this work, the problem of applying Zero Padding (ZP) as redundancy in multicarrier communications is addressed. To this goal, a general matrix formulation to recover the trans- mitted symbol when ZP is used, is provided for any kind of discrete transform employed at both the transmitter and the receiver. The obtained result not only generalizes some previously reported techniques, such as discrete Fourier transform-based transceivers, but it also allows to extend it to other kind of transforms (e.g., discrete trigonometric transforms). As a particular case study, the use of discrete cosine transform Type-II even (DCT2e) is analyzed. In this case, a simple structure that recover the transmitted symbol at the receiver is also shown. Additionally, the expressions of the one-tap per subcarrier coefficients, also using the DCT2e, are derived.