Citation

Abstract

The purpose of the research is to obtain results toward effective methods for combating the deleterious effects of various impairments arising in digital data transmission over dually polarized communication channels, namely, metal telephone line, coaxial cable, radio channel and optical fiber.

The improvements in spectral efficiency can cause more co-channel interference (CCI) and adjacent-channel interference (ACI). Moreover, transmission of M-state Quadrature Amplitude Modulated (QAM) signals via orthogonally (vertical and horizontal) polarized carriers is an effective method for reusing existing bandwidth with the advantages of more system capacity and higher bit rate. However, the obstacle in the way of realizing these advantages is the unavoidable presence of cross-polarization interference (CPI) between two polarized signals. Channel equalization is a well-established theory when dealing with optimal communications system design. It is the technique employed in this research.

The utilization of wide transmitter and receiver bandwidth in order to suppress CCI, ACI and CPI over a dually polarized channel will be the first contribution of this research. The second contribution will be the study of the conditions to suppress all the interference by the generalized zero-forcing equalizer. These conditions are the transmitter bandwidth, receiver bandwidth, carrier spacing, and co-channel interference.