Wireless Cooperative Video Coding Using a Hybrid Digital–Analog Scheme
Wireless video broadcast/multicast and mobile video communication pose a challenge to the conventional video transmission strategy (which applies separate digital source coding and digital channel coding in a point-to-point communication system) and, therefore, cooperative communication has been proposed to improve the received quality of the receivers with bad channels and the robustness to fading (mobility). In this paper we propose a novel wireless cooperative video coding (WCVC) framework. Specifically, we present a cooperative joint source-channel coding scheme that is based on hybrid digital-analog coding and integrates the advantages of digital coding and analog coding. Compared with most state-of-the-art cooperative video delivery methods, no matter for cooperation scenario or noncooperation scenario, the proposed scheme can avoid the staircase effect and realize continuous quality scalability on condition that the channel quality is within the expected range, and it has strong adaptability to channel variation with higher coding efficiency and better fairness among all receivers. Therefore, it is very suitable for wireless cooperative/noncooperative video broadcast/multicast transmission and cooperative/noncooperative mobile video applications. The experimental results show that the proposed WCVC outperforms SoftCast (which is a new analog scheme) and SVC + hierarchical modulation (HM) (which combines H.264/SVC codec and HM technique) no matter the noncooperative scenario or for cooperative scenario, which verify the effectiveness of our proposed WCVC framework.