Design and investigation of hybrid PON-FSO system employing modified NZCC code under distinct weather conditions.

In this paper, a hybrid time and wavelength division multiplexing passive optical network (TWDM-PON) and wavelength division multiplexing optical code division multiple access (WDM-OCDMA) with free space optics (FSO) for bidirectional 160/40 Gbps transmission has been proposed. Also, to offer the information to 64 users over 60 km fiber and 600 m FSO channels under diverse climate conditions have been presented. Also, to resist the fiber impairments, interference, noise and losses under the effect of unfavorable climate conditions in hybrid fiber-FSO link, a modified new zero-cross correlation (NZCC) code is effectively used in the system to enhance the system ability to access shared bandwidth with users' security. The performance of the designed PON system has been analysed and investigated for diverse FSO (10-600 m) and fiber distance (0-60 km) under distinct climate conditions. Based on mathematical and simulation analysis, the designed system using modified NZCC code is shown to provide better performance than other OCDMA codes. The designed system with hybrid fiber-FSO link improves the performance of the system in terms of high received optical power of 3 dBm and support 110 users simultaneously at acceptable BER of 10(-9), under fiber impairments, climate conditions and turbulences. Additionally, on comparing the designed system's performance with the prior latest work in literature reveals its superiority than others in codes and system design.