In this paper, we characterize the performance of relay-assisted underwaterwireless optical code division multiple access (OCDMA) networks over turbulentchannels. In addition to scattering and absorption effects of underwaterchannels, we also consider optical turbulence as a log-normal fadingcoefficient in our analysis. To simultaneously and asynchronously share mediumamong many users, we assign a unique optical orthogonal code (OOC) to each userin order to actualize OCDMA-based underwater network. The most significantchallenge in underwater optical communication is in the ability to extend theshort range of its coverage. In order to expand the viable communication range,we consider multi-hop transmission to the destination. Moreover, we evaluatethe performance of a relay-assisted point-to-point UWOC system as a specialcase of the proposed relay-assisted OCDMA network. Our numerical resultsindicate significant performance improvement by employing intermediate relays,e.g., one can achieve $32$ {dB} improvement in the bit error rate (BER) of$10^{-6}$ using only a dual-hop transmission in a $90$ {m} point-to-point clearocean link.
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