A Streaming Method for Efficient Bandwidth Utilization using QoS Control Function of LTE

摘要

Recently, mobile video streaming services become very popular. MPEG-DASH is one of the streaming schemes used for the service. In this method, a mobile terminal tries to download video chunks from a streaming server by estimating the available bandwidth of the underlying network. However, it is very difficult to estimate the available bandwidth because this method is working as an OTT (over the top) service, which means the network is regarded as a dumb pipe. Therefore some of the downloaded video chunks are discarded when the estimation is wrong. Since wireless spectrum is a very precious resource, the wasted chunks (downloaded then discarded) should be avoided. We propose a novel video streaming method in which a QoS (Quality of Service) control function of a mobile network is utilized. In the proposed method, an original video content is encoded into multiple layers. There are two kinds of layers, a base layer and an enhancement layer. The base layer is small in size but includes all the necessary information to keep playing the video content. The enhancement layer is large in size and provides better image quality when decoded with a corresponding base layer. Then the base layer is prioritized by the QoS control function in the mobile network when it is delivered to a mobile terminal. On the other hand, the enhancement layer is delivered in a best effort manner. In this way, even if there were no available bandwidth for both of the layers, the mobile terminal can keep playing the video by using the prioritized base layer. Since the enhancement layer is discarded before the wireless transmission when it is congested, the wireless spectrum is efficiently used.