Priority Encoding Transmission

We introduce a novel approach for sending messages over lossy packet-based networks. The new method, called Priority Encoding Transmission, allows a user to specify a different priority on each segment of the message. Based on the priorities, the sender uses the system to encode the segments into packets for transmission. The system ensures recovery of the segments in order of their priority. The priority of a segment determines the minimum number of packets sufficient to recover the segment. We define a measure for a set of priorities, called the rate, which dictates how much information about the message must be contained in each bit of the encoding. We develop systems for implementing any set of priorities with rate equal to one. We also give an information-theoretic proof that there is no system that implements a set of priorities with rate greater than one. This work has applications to multi-media and high speed networks applications, especially in those with bursty sources and multiple receivers with heterogeneous capabilities. *International Computer Science Institute, Berkeley, California International Computer Science Institute. Berkeley, California. Partially supported by NSF operating grant CCR-9304722, and ESPRIT BR Grant EC-US 030. $International Computer Science Institute, Berkeley, California. Supported by an NSF postdoctoral fellowship and by a Canadian NSERC postdoctoral fellowship. §International Computer Science Institute, Berkeley, California. Partially supported by NSF operating grant CCR-9304722, Israeli-U.S. NSF BiNational Science Foundation grant No. 92-00226 and ESPRIT BR Grant EC-US 030. ‘IBM Thomas J. Watson Research Center, Yorktown Heights, New York. Participated in research while visiting the International Computer Science Institute.