Fast-decodable MIMO HARQ systems

Seyyed Saleh Hosseini, Jamshid Abouei, Murat Uysal

Research output: Contribution to journalArticlepeer-review


This paper presents a comprehensive study on the problem of decoding complexity in a Multi-Input Multi-Output (MIMO) Hybrid Automatic Repeat reQuest (HARQ) system based on Space-Time Block Codes (STBCs).We show that there exist two classes of fast-decodableMIMO HARQ systems: independent and dependent STBC structures. For the independent class, two types of protocols namely, fixed and adaptive threshold-based are presented and their effectiveness in both computational complexity reduction and spectral efficiency preservation are discussed. For the dependent class, a fast Sphere Decoder (SD) algorithm with a low computational complexity is proposed for decoding process of HARQ rounds. Two new concepts are introduced to leverage the fast-decodable notion in MIMO HARQ systems. Simulation results show that the proposed fast-decodable MIMO HARQ protocols in both classes provide a significant reduction in the decoding complexity as compared with the original MIMO HARQ method.

Original languageEnglish (US)
Article number7018101
Pages (from-to)2827-2840
Number of pages14
JournalIEEE Transactions on Wireless Communications
Issue number5
StatePublished - May 1 2015


  • Fast-decodable
  • Hybrid automatic repeat request (HARQ) systems
  • Multi-Input Multi-Output (MIMO)
  • Space-Time Block Codes (STBCs)
  • Sphere Decoder (SD) algorithm

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


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