Performance of LDPC Decoders with Missing Connections

Linjia Chang, Avhishek Chatterjee, Lav R. Varshney

Research output: Contribution to journalArticlepeer-review


Due to process variation in nanoscale manufacturing, there may be permanently missing connections in information processing hardware. Due to timing errors in circuits, there may be missed messages in intra-chip communications, equivalent to transiently missing connections. In this paper, we investigate the performance of message-passing LDPC decoders in the presence of missing connections. We prove concentration and convergence theorems that validate the use of density evolution performance analysis. Arbitrarily small error probability is not possible with missing connections, but we find suitably defined decoding thresholds for communication systems with binary erasure channels under peeling decoding, as well as binary symmetric channels under Gallager A and B decoding. We see that decoding is robust to missing wires, as decoding thresholds degrade smoothly. Moreover, there is a stochastic facilitation effect in Gallager B decoders with missing connections. We also conduct finite-length simulations, compare the decoding sensitivity to channel noise and to missing wiring, and perform preliminary error-tolerant manufacturing yield analysis.

Original languageEnglish (US)
Article number7776825
Pages (from-to)511-524
Number of pages14
JournalIEEE Transactions on Communications
Issue number2
StatePublished - Feb 2017


  • Decoding
  • error analysis
  • message passing
  • stochastic facilitation
  • wiring

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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