CMPSCI Theory Seminar

Protocols for Asymmetric Communication Channels

Louis Theran, UMass Amherst

29 April 2003

4:00 p.m., Room 142 Computer Science Building

Note:My apologies to anyone forced to miss this seminar because they are protesting in Boston. I'm afraid we've lost too many seminar sessions this term for me to reschedule another one -- DAMB.

Many recent and emerging network technologies offer substantially more bandwidth in one direction than the other. Adler and Maggs introduced a communication model for this scenario and show that a high-speed link from server to client can be used to greatly reduce the number of bits sent across the slower client to server link.

The model features a client sending an n-bit string to a server over an asymmetric channel, with only the server able to access the distribution D from which the client's string is drawn. Adler and Maggs present several protocols in which the number of server and client bits are, respectively, O(n) and O(H(D)+1), where H(D) is the binary entropy of the distribution D. I will present the communication model and a new variant of the protocol Round-efficient from the Adler and Maggs paper. Like Round-efficient, our protocol is existentially optimal. The new work reduces the computational requirements of Round-efficient from O(2n) to O(n2^H(D)).










Last modified 25 April 2003