Client-Driven Joint Cache Management and Rate Adaptation for Dynamic Adaptive Streaming over HTTP

Due to the fact that proxy-driven proxy cache management and the client-driven streaming solution of Dynamic Adaptive Streaming over HTTP (DASH) are two independent processes, some difficulties and challenges arise in media data management at the proxy cache and rate adaptation at the DASH client. This paper presents a novel client-driven joint proxy cache management and DASH rate adaptation method, named CLICRA, which moves prefetching intelligence from the proxy cache to the client. Based on the philosophy of CLICRA, this paper proposes a rate adaptation algorithm, which selects bitrates for the next media segments to be requested by using the predicted buffered media time in the client. CLICRA is realized by conveying information on the segments that are likely to be fetched subsequently to the proxy cache so that it can use the information for prefetching. Simulation results show that the proposed method outperforms the conventional segment-fetch-time-based rate adaptation and the proxy-driven proxy cache management significantly not only in streaming quality at the client but also in bandwidth and storage usage in proxy caches. 1. Introduction Recently, Hypertext Transfer Protocol (HTTP) [1] has been widely used for the delivery of real-time multimedia content over the Internet, such as in video streaming applications. Unlike Realtime Transport Protocol (RTP) over User Datagram Protocol (UDP), HTTP typically traverses through firewalls and network address translators (NATs), which makes it attractive for multimedia streaming applications. Kim and Ammar [2] reported that short-term transmission rate variation in HTTP/TCP can be smoothed out through buffering at the receiver side. Recently, standardization projects on dynamic adaptive streaming over HTTP have been carried out, which are briefly reviewed next. Adaptive HTTP streaming (AHS) was first standardized in Release 9 of the packet-switched streaming (PSS) service [3] by the Third Generation Partnership Project (3GPP). The Moving Picture Experts Group (MPEG) took 3GPP AHS Release 9 as a starting point for its newly published MPEG Dynamic Adaptive Streaming over HTTP (DASH) standard [4]. 3GPP continued to work on adaptive HTTP streaming in communication with MPEG and recently published the 3GP-DASH standard [5]. MPEG DASH and 3GP-DASH have a common core and are therefore collectively referred to as DASH in this paper. In DASH, a client continuously requests and receives small segments of multimedia content, denoted as media segments. Rate adaptation can be easily supported by requesting media