Massive Connectivity with Massive MIMO - Part I: Device Activity Detection and Channel Estimation

Liang Liu, Wei Yu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

386 Citations (Scopus)


This two-part paper considers an uplink massive device communication scenario in which a large number of devices are connected to a base station (BS), but user traffic is sporadic so that in any given coherence interval, only a subset of users is active. The objective is to quantify the cost of active user detection and channel estimation and to characterize the overall achievable rate of a grant-free two-phase access scheme in which device activity detection and channel estimation are performed jointly using pilot sequences in the first phase and data is transmitted in the second phase. In order to accommodate a large number of simultaneously transmitting devices, this paper studies an asymptotic regime where the BS is equipped with a massive number of antennas. The main contributions of Part I of this paper are as follows. First, we note that as a consequence of having a large pool of potentially active devices but limited coherence time, the pilot sequences cannot all be orthogonal. However, despite the nonorthogonality, this paper shows that in the asymptotic massive multiple-input multiple-output regime, both the missed device detection and the false alarm probabilities for activity detection can always be made to go to zero by utilizing compressed sensing techniques that exploit sparsity in the user activity pattern. Part II of this paper further characterizes the achievable rates using the proposed scheme and quantifies the cost of using nonorthogonal pilot sequences for channel estimation in achievable rates.

Original languageEnglish
Pages (from-to)2933-2946
Number of pages14
JournalIEEE Transactions on Signal Processing
Issue number11
Publication statusPublished - 1 Jun 2018
Externally publishedYes


  • approximate message passing (AMP)
  • Compressed sensing
  • Internet-of-Things (IoT)
  • machine-type communications (MTC)
  • massive connectivity
  • massive multiple-input multiple-output (MIMO)
  • state evolution

ASJC Scopus subject areas

  • Signal Processing
  • Electrical and Electronic Engineering


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