A framework to unify HS-OFDM, OCDM, SCCP, and OSDM schemes under certain interference

Abstract

This thesis investigates the impacts of interference caused by cyclic prefix (CP) violation and symbol timing offset (STO) in data communication schemes applied to power line communication (PLC) when different types of schemes are taken into account. In this context, it is presented a framework capable of unifying a set of data communication schemes, which uses the fast Fourier transform, when the aforementioned problems are considered. Based on the framework, closed-form equations are presented for the orthogonal chirp division multiplexing (OCDM), single carrier cyclic prefix (SCCP, and orthogonal Stockwell division multiplexing (OSDM). Relying on the derived expressions, this thesys shows that the OCDM, SCCP, and OSDM schemes present a normalized signal-to-noise ratio (nSNR) equal to the harmonic mean of the nSNR presented by the hermetian symmetric orthogonal frequency division multiplexing (HS-OFDM) scheme. Furthermore, the framework’s ability to derive the HS-OFDM, OCDM, SCCP, and OSDM schemes from the same mathematical formulation facilitates the design of transceivers for those schemes, in which each of them presents diffenrents advantages and disadvanges in relation to specifics characteristics of the data communication media. This thesys also discusses the numerical analysis between the HS-OFDM, OCDM, SCCP, and OSDM for different levels of CP violation and STO when the data communication channels are modeled as linear and time invariant systems, which occupy the frequency width of 0 to 500 kHz and is disturbed by an additive noise modeled as white and colored Gaussian random process. The numerical analysis is based on the data rate, which allows uniform allocation (UA) and optimal allocation (OA), and bit error probability, which uses adaptative modulation to allocate the same amount of bits in each subcarrier (HS-OFDM), subchirp (OCDM), subsymbol (SCCP) and tile (OSDM). Considering that channel state information (CSI) is completely known by the transmitter, the main parameter for the analysis is the data rate. However, when CSI is not known at the transmitter side, the bit error probability is the main parameter. The data rate results show that HS-OFDM is the best scheme, followed by the OSDM, whilst the bit error probability results show the OCDM as the better one. Finally, the present thesis demonstrates that the unified mathematical formulation allows a comparative analysis of various data communication schemes when different scenarios with distinct problems are considered.