Using NLMS-TEQ to reduce CP length for 20.48 Gb/s direct-detection optical OFDM transmission over 2400 km of SSMF

Normalized Least Mean Squares-Time Domain Equalizer (NMLS-TEQ) is used to reduce the cyclic prefix (CP) length in direct-detection optical orthogonal frequency division multiplexing (O-OFDM) transmission over 2400 km of Standard Single Mode Fiber (SSMF). The aim of using NLMS-TEQ is to solve the problem of choosing the gain of Least Mean Square (LMS) algorithm to make it stable since LMS algorithm is sensitive to the scaling of its input. The NMLS-TEQ can cancel the residual Inter Symbol Interference (ISI) caused by both the Group Velocity Dispersion (GVD) and the CP length being shorter than the Channel Impulse Response (C1R). Using NLMS-TEQ reduces size of the CP, and consequently leading to system performance improvement. (C) 2013 Elsevier GmbH. All rights reserved.