Turbo码有效自由距离d_2上限的证明

THE PROOF OF UPPER BOUNDS OF EFFECTIVE FREE DISTANCE FOR TURBO CODE

Turbo码是一种新的纠错码,具有十分突出的纠错能力。Turbo码编码器由两个或两个以上的分量码编码器和交织器并行级联而成。S.Benedetto和G.Montersi(1996)中提出了设计Turbo码的新参数——有效自由距离d_2(Effective Free Distance)。D.Divsalar和R.J.McEliece(1996)给出了有效自由距离的两个上限,但未给出证明。本文从理论上对d_2的两个上限进行证明。

Turbo code is a new class of error correcting and achieves almost reliable commu-nication when SNR is very close to the Shannon-Limit. Turbo encoder consists of a parallel concatenation of two or more convolutional codes and interleaver. A new parameter effective free distance d2 was proposed by S. Benedetto and G. Montorsi(1996) and two upper bounds on d2 were stated without proof by D. Divsalar and R. J. McEliece (1996). This paper proofs the two upper bounds on d2.