ADAPTIVE BROADBAND VIDEO STREAMING FOR IPTV WIRELESS ACCESS

摘要

Broadband wireless access supports mobile applications, which may soon extend to Internet Protocol TV (IPTV). IPTV streaming from a localized server is likely to be across a wired path through a metro network before crossing the wireless link. In this scenario, the paper proposes Broadband Video Streaming (BVS), which enhances UDP transport with a single, negatively acknowledged, lost packet retransmission. Taking IEEE 802.16e access as an example, results demonstrate that BVS is sufficiently able to compensate for packet losses without overly increasing delay and without the overhead of application forward error correction, whereas unembellished UDP, and two alternative congestion controllers (single- and multi-connection versions of TCP-Friendly Rate Control (TFRC)) are unable to both reduce packet loss and streaming delay. The paper exposes asymmetrical streaming behavior between downlink and uplink streaming and finds that, for downlink streaming, packet reordering by video picture-type packet is sensible. The paper then extends the classic BVS scheme with an adaptive scheme that takes into account whether packet losses are from congestion or wireless channel conditions or a mixture of both. To cope with this, adaptive BVS adopts differentiated lost packet retransmission according to the picture type of a lost packet. It is found that for greater packet loss, adaptive BVS achieves equivalent objective video quality to BVS but with reduced delay and bandwidth consumption.