Transcoding Based Video Caching Systems: Model and Algorithm

Table 1

Symbol definition.

Symbols	Definition
	A set of all cache servers.
	A set of all videos.
	A set of all quality versions of a video.
	Cache space of server .
	Size of file (), i.e., quality version of video .
	Number of requests for file from the users under base station .
	Unit data delivery delay from remote source server to a user under base
	station .
	Unit data delivery delay from server to a user under base station
	Delivery delay of server for serving all its local requests in independent
	caching.
	Delivery delay of server for serving its local requests for all versions of
	video in independent caching.
	Delivery delay for serving all requests from all users in
	cooperative caching.
	Delivery delay for serving the requests from all users for
	all versions of video in cooperative caching.
	Caching vector, where each element equals the quality version of
	video to be cached at server while means no file related to
	video is cached at server .