Flexible FEC and Fair Selection of Scalable Units for High Quality VOD Streaming Service Over Wireless Networks

Abstract

Providing high quality video on demand (VoD) streaming service over wireless networks is very challenging due to the limited capacity and error-proneness of the wireless environment. We propose a flexible forward error correction (FEC) and a fair selection scheme of scalable units that utilize a layered coding structure of H.264/SVC (scalable video coding). Three error-resilient techniques (e.g., unequal error protection, FEC, and retransmission) are adapted to minimize the total distortion of VoD streaming service. For flexible FEC, a rate-less FEC code is adopted. The FEC code rates are based on the possible number of retransmission, the condition of the wireless channel and the layered coding structure of H.264/SVC for each packet. A theoretical study is performed to show how to utilize the possible number of retransmission for an adaptive FEC code rate. With fair selection, regular and retransmission-requested packets compete for resources without fixing the retry limit. Thus, excessive retransmission is prevented and the proposed scheme effectively provides capacity-limited and delay-constrained VoD streaming services. For this fair selection of scalable units, we formulate the problem using binary integer programming and propose an effective low complexity selection algorithm based on a priority index. The proposed algorithm prioritizes packets according to the priority index and the H.264/SVC structure. We show that the proposed scheme can minimize the total video distortion compared to other heuristic procedures. Other effects of the various factors are also considered for the performance of the new scheme.