Distortion-aware MIMO link adaptation for enhanced multimedia communications

In wireless multimedia communications, optimizing the quality of user experience is a major design goal, which is often quantified by the end-to-end distortion between the actual multimedia source at the encoder and its reconstructed version at the decoder. Joint source-channel coding (JSCC) techniques aim to optimize codec and radio system parameters in order to minimize end-to-end distortion and yield enhanced quality of user experience when compared with separate source-channel coding techniques. With the motivation of applying JSCC-based cross-layer optimizations to PHY/MAC layer design for practical wireless systems, this paper proposes new techniques for MIMO link adaptation toward enhanced multimedia communications. In particular, we propose new distortion-aware MIMO link adaptation techniques toward the selection of modulation and coding schemes (MCS) and MIMO space-time modulation (including MIMO diversity and spatial multiplexing) schemes with the objective of minimizing end-to-end distortion, different from classical approaches that aimed for other optimizations such as maximizing spectral efficiency or goodput. Furthermore, we investigate the performance of distortion-aware MIMO link adaptation in realistic link-level simulation (LLS) and system-level simulation (SLS) environments based on orthogonal frequency division multiplexing (OFDM) under broadband frequency-selective fading with special focus on multicast broadcast services (MBS), and demonstrate their advantages over goodput-maximizing MIMO link adaptation techniques in terms of reduced end-to-end distortion and higher peak signal-to-noise ratio (PSNR).