Iteration-constrained design of IRA codes
Alex J. Grant, Land, Ingmar, Wang, Guangsong · Repository for Publications and Research Data (ETH Zurich) · 2012
This paper addresses extrinsic information chart based design of non-systematic irregular repeat-accumulate codes for a given number of decoding iterations.This criterion is of practical importance in many applications where complexity or latency is limited.Our main contribution is a novel formulation of the optimzation problem in a particular way that makes its actual evaluation possible.This is achieved by introducing additional optimization variables and constraints which have the effect of "unrolling" the iteration.Our approach enforces the finite iteration condition, while avoiding the need to know arbitrary repeated functional compositions of the component EXIT functions.We restrict attention to the binary erasure channel, for which the EXIT chart approach is exact.Extension to other sparse-graph codes and other communication channels is straightforward.