Analysis of Carrier Frequency Offset Distribution on Efficiency of Multicarrier Spread Spectrum Techniques

In this era of telecommunications multi-carrier is the leading technology of choice. Multicarrier Spread Spectrum (MCSS) is a promising communication technique. It was introduced with three fundamental types, multi-carrier code-division-multiple-access (MC-CDMA), multi-carrier direct-sequence CDMA (MC-DS-CDMA) and Multi-tone CDMA (MT-CDMA). Though MCSS is robust to multi-path fading and immune to inter symbol interference, it shows sensitivity towards Carrier Frequency Offset (CFO) and synchronization errors. CFO gives rise to Inter Carrier Interference (ICI) and Multiple Access Interference (MAI). ICI and MAI deteriorate the spectral efficiency along with noise and self-interference. We analyze the impact of different distributions of CFO among the interferers on the spectral efficiency in Rayleigh fading environment for all three categories of MCSS. We also analyzed the role of variance of CFO on the spectral efficiency. Simulation results unveil the effect that efficiency of the system gradually increases with increase in the variance of CFO. We have also done comparison for Gaussian distribution of triangle k with uniform triangle k by plotting spectral efficiency against variance, SINR and interferers.