Logical Superposition Coded Modulation for Wireless Video Multicasting
Ho, James Ching-Chih
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This thesis documents the design of logical superposition coded (SPC) modulation for implementation in wireless video multicast systems, to tackle the issues caused by multi-user channel diversity, one of the legacy problems due to the nature of wireless video multicasting. The framework generates a logical SPC modulated signal by mapping successively refinable information bits into a single signal constellation with modifications in the MAC-layer software. The transmitted logical SPC signals not only manipulatively mimic SPC signals generated by the superposition of multiple modulated signals in the conventional hardware-based SPC modulation, but also yield comparable performance gains when provided with the knowledge of information bits dependencies and receiver channel distributions. At the receiving end, the proposed approach only requires simple modifications in the MAC layer software, which demonstrates full decoding compatibility with the conventional multi-stage signal-interference cancellation (SIC) approach involving additional hardware devices. Generalized formulations for symbol error rate (SER) are derived for performance evaluations and comparisons with the conventional hardware-based approach.