| Summary: | <p>The visible light communication (VLC) system has been considered as an alternative indoor communication method for future networks. The VLC system requires highly sensitive receivers. At present, the best existing VLC receiver is based on the Avalanche photodiode (APD). However, the excess noise generated within the APD limits its sensitivity. The excess noise can be avoided by biasing the APD over its breakdown voltage to create a single photon avalanche diode (SPAD). It is expected that the SPAD can be used to develop the more sensitive VLC receiver.</p> <p>At present, the sensitivity of the current SPADs is limited by several non- idealities, and the circumstances in which the SPADs should be preferred to APDs are still unclear. In this thesis, the first attempt at comparing the sensitivity of the SPAD-based receiver and the APD-based receiver has been presented. To figure out the criteria that determine a SPAD-based receiver is more sensitive than an APD-based receiver, analytical models for estimating the impact of the non-idealities on the SPAD-based re- ceiver's sensitivity have been introduced and verified. Based on those val- idated models, appropriate guidelines for making a SPAD-based receiver superior to the APD-based receiver in the typical indoor environment are presented.</p> <p>Pulse amplitude modulation (PAM) is potentially an attractive modula- tion scheme for the SPAD-based receiver to meet the demand for the high data rate due to its simplicity in the transmitter and receiver design. In this thesis, the efficient ways of using the SPAD-based receiver to support PAM are investigated.</p> <p>The SPAD arrays tested in this project are not optimised for the VLC application. Since SPADs are a relatively new technology, unlike APDs, the newly released product has significantly better characteristics than their predecessors. Based on the validated analytical models, it is esti- mated that the newly released SPAD arrays have the potential to support Gbps data rate with a higher sensitivity than the conventional APD in the typical indoor environment.</p>
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