A Simple Converse of Burnashev's Reliability Function

Berlin, Peter
Nakiboğlu, Barış
Rimoldi, Bixio
Telatar, Emre İ
In a remarkable paper published in 1976, Burnashev determined the reliability function of variable-length block codes over discrete memoryless channels (DMCs) with feedback. Subsequently, an alternative achievability proof was obtained by Yamamoto and Itoh via a particularly simple and instructive scheme. Their idea is to alternate between a communication and a confirmation phase until the receiver detects the codeword used by the sender to acknowledge that the message is correct. We provide a converse that parallels the Yamamoto-Itoh achievability construction. Besides being simpler than the original, the proposed converse suggests that a communication and a confirmation phase are implicit in any scheme for which the probability of error decreases with the largest possible exponent. The proposed converse also makes it intuitively clear why the terms that appear in Burnashev's exponent are necessary.

Citation Formats
P. Berlin, B. Nakiboğlu, B. Rimoldi, and E. İ. Telatar, “A Simple Converse of Burnashev’s Reliability Function,” IEEE TRANSACTIONS ON INFORMATION THEORY, vol. 55, no. 7, pp. 3074–3080, 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48630.