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Initial ranging scheme based on interpolated Zadoff-Chu sequences for OFDMA-PON

: Razmtouz, A.; Habel, K.; Kottke, C.; Ruprecht, C.; Rosenkranz, W.

Postprint (PDF; )

Optics Express 22 (2014), No.3, pp.3669-3674
ISSN: 1094-4087
Bundesministerium für Bildung und Forschung BMBF
01BP1031, 16BP1136
Journal Article, Electronic Publication
Fraunhofer HHI ()

Initial access to passive optical networks (PONs) requires upstream (US) synchronization of multiple optical network units (ONUs). We propose a low-complexity scheme for orthogonal frequency division multiple access (OFDMA) based PONs and demonstrate it experimentally. The scheme is based on interpolated Zadoff-Chu sequences, to synchronize the signal of each ONU arriving at the optical line terminal (OLT). Our experimental test bed consists of 4 colorless ONUs seeded by a single laser located at the OLT. Thermal expansion of a fiber is utilized to emulate a dynamic time drift in the demodulation-window positioning of OLT. The detected individual offsets at the OLT are fed back to the ONUs and are compensated at every data frame transmission. In this way, both inter carrier interference (ICI) and inter symbol interference (ISI) remain below acceptable levels.