Absolute Added Correlative Coding using APDs for LEO-LEO OISLs

In this paper, the absolute added correlative coding (AACC), a multilevel intensity modulation and direct-detection (IM/DD) format, is applied to an optical wireless communication (OWC) system and modelled to simulate an optical inter-satellite link (OISL) operating in a low Earth orbit (LEO) satellite broadband constellation network. It uses an avalanche photodiode (APD) paired with a transimpedance amplifier (TIA) as its receiver front-end (RFE). The modelled APD AACC modulated link is then evaluated for several OISL parameters. These include its power efficiency, supported transmission ranges, telescope pointing error angles, telescope aperture diameter sizes and receiver sensitivity. For each parameter, the performance of the link is further compared to its PIN equivalent, the PIN AACC modulated OISL, and a 4-pulse amplitude modulated (4-PAM) OISL. At a bit rate of 10 Gbps, the modelled APD AACC modulated OISL observed to outperform the latter two links for all five parameters whilst keeping to the bit-error rate (BER) requirement of 10
^-9
. The link also noted an increase in receiver sensitivity as it recorded a 4 dB and 11 dB improvement in signal-to-noise ratio (SNR) against the PIN AACC and 4-PAM modulated OISLs, respectively.