Volterra/Hybrid Equalization of Nonlinear ISI in a Magneto-Optic Data Storage Channel

This paper presents performance analysis of an adaptive Volterra/Hybrid equalizer in a nonlinear magneto-optic data storage channel. In a data storage system, nonlinear intersymbol interference (ISI) is one of the limiting factors for high storage density. Volterra and Hybrid (combination of linear and Volterra) equalizers are proposed and developed for compensation of nonlinear ISI. The use of Volterra/Hybrid equalizers provided an extra 1.3-1.5 dB SNR gain over linear equalizers. Performance and complexity of these equalizers are compared. Convergence issues are also investigated by examining the eigenvalue spread of the covariance matrix. The techniques proposed here are applicable to other communication systems (e.g. wireless, optical) exhibiting nonlinear ISI characteristics. Key-Words: ISI, Nonlinear Equalization, Volterra, Optical Data Storage, SNR, eigenvalue, convergence ratio