Wireless real time video applications have become popular with the proliferation of wireless communication systems. However error prone and bandlimited nature of wireless channels make it challenging to provide reliable real time high quality video streaming to users. In order to provide robustness against fading and improve error rates, multiple input multiple output (MIMO) technology is widely used.
Space time coding (STC) is used to provide diversity in MIMO systems. It is known that there is a trade-off between rate and diversity of STC, i.e. the rate is sacrificed for increased protection. Diversity embedded space time codes (DESTC) provide a high rate code which also contains higher diversity layer(s) underneath. When the channel has a high received signal to noise ratio all the transmitted symbols can be decoded whereas under severe fading high diversity symbols may still be decodable. Therefore by providing unequal error protection for multiple layers of source streams simultaneously, DESTC makes an opportunistic use of the channel. In this paper, we explore how to make use of this property of DESTC to efficiently transmit layered video streams to a single or multiple users over wireless channels.
Layered video transmission with unequal error protection is a popular research area. The extensive work in the literature on layered video transmission over both single antenna and multi antenna systems via STC and other channel codes provide unequal error protection by using different channel codes in a time division multiplexing (TDM) fashion. But DESTC, by enabling simultaneous transmission of many layers, is a good alternative for wireless video delivery, particularly for multicast systems where users have a broad range of channel conditions. While using DESTC for scalable image transmission is considered, video transmission using DESTC is still an open area for research.
In this project we consider delivery of layered video coded with the scalable video coding (SVC) extension of the H.264/AVC standard using DESTC for wireless unicast and multicast applications.
This research is partially funded by NSF, WICAT