MIMO-Based Reliable Grant-Free Massive Access with QoS Differentiation for 5G and beyond

Ameha Tsegaye Abebe, Chung G. Kang

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Grant-free (GF) access has been one of the enablers for the various use cases in 5th generation (5G) mobile system, especially for time-critical massive machine-type communication (mMTC). However, these use cases have diverse quality of service (QoS) requirements, which can be measured in terms of an access success rate from a GF random access perspective. Consequently, a GF scheme that enables supporting of diverse QoS is highly sought. This article proposes a GF access scheme in which high-QoS users superpose multiple preambles to improve their access success rate as a result of the diversity in access collision and multiple access interference seen by multiple preambles. We further show that in the presence of multiple antennas in the base station (BS), a low-complexity receiver can correctly detect active preambles with a significantly high probability, even under severe multiple access interference caused by non-orthogonal preamble transmission. A theoritical performance analysis is conducted by modeling the preamble reception as a multiple measurement vector-based compressive sensing problem. The preamble misdetection probability is shown to decrease exponentially as the number antennas at BS increases. Numerical results demonstrate multiple-order improvement in terms of the access success rate for critical-QoS users, even under severe noise and multiple access contamination.

Original languageEnglish
Article number9189944
Pages (from-to)773-787
Number of pages15
JournalIEEE Journal on Selected Areas in Communications
Issue number3
Publication statusPublished - 2021 Mar


  • Grant-free access
  • MIMO
  • mMTC
  • non-orthogonal Zadoff-Chu sequences
  • quality-of-services (QoS)
  • uRLLC

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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