SSIM based Resource Optimization for Multiuser Downlink OFDM Video Transmission Systems

Wireless networks are poised to facilitate various looming multimedia streaming applications. With the expansion of wireless networks from a simple data transfer to delay sensitive and bandwidth-intense multimedia applications, addressing of quality of service (QoS) issues become imperative. In the proposed work, we model the video rate distortion (RD) using a distortion metric called structural similarity (SSIM) index to investigate the resource allocation and optimization issues for the transmission of multimedia traffic over wireless networks with QoS constraints. We formulate a cross-layer problem; that achieves equal structural similarity of multi-resolution video sequences among users by introducing a set of proportional rate constraints. The channel state information (CSI) from physical layer along with rate distortion (RD) information of application layer are used for allocating power and spectrum resources. Performance analysis of users preferring different video resolutions is done for a downlink system that uses orthogonal frequency division multiple access (OFDMA. With the proposed cross-layer resource allocation, SSIM is ensured equally among users. Results of bit-level simulation studies are shown for establishing the performance of the proposed method.