Large-scale multiuser SM-MIMO versus massive MIMO

T. Lakshmi Narasimhan, P. Raviteja, A. Chockalingam

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearch

51 Citations (Scopus)


Spatial modulation (SM) is attractive for multi-antenna wireless communications. SM uses multiple transmit antenna elements but only one transmit radio frequency (RF) chain. In SM, in addition to the information bits conveyed through conventional modulation symbols (e.g., QAM), the index of the active transmit antenna also conveys information bits. In this paper, we establish that SM has significant signal-to-noise (SNR) advantage over conventional modulation in large-scale multiuser (multiple-input multiple-output) MIMO systems. Our new contribution in this paper addresses the key issue of large-dimension signal processing at the base station (BS) receiver (e.g., signal detection) in large-scale multiuser SM-MIMO systems, where each user is equipped with multiple transmit antennas (e.g., 2 or 4 antennas) but only one transmit RF chain, and the BS is equipped with tens to hundreds of (e.g., 128) receive antennas. Specifically, we propose two novel algorithms for detection of large-scale SM-MIMO signals at the BS; one is based on message passing and the other is based on local search. The proposed algorithms achieve very good performance and scale well. For the same spectral efficiency, multiuser SM-MIMO outperforms conventional multiuser MIMO (recently being referred to as massive MIMO) by several dBs. The SNR advantage of SM-MIMO over massive MIMO can be attributed to: (i) because of the spatial index bits, SM-MIMO can use a lower-order QAM alphabet compared to that in massive MIMO to achieve the same spectral efficiency, and (ii) for the same spectral efficiency and QAM size, massive MIMO will need more spatial streams per user which leads to increased spatial interference.

Original languageEnglish
Title of host publication2014 Information Theory and Applications Workshop (ITA)
Subtitle of host publicationConference Proceedings
EditorsScott Blair
Place of PublicationPiscataway NJ USA
PublisherIEEE, Institute of Electrical and Electronics Engineers
Number of pages9
ISBN (Print)9781479935895
Publication statusPublished - 2014
Externally publishedYes
EventInformation Theory and Applications Workshop (ITA) 2014 - San Diego, United States of America
Duration: 9 Feb 201414 Feb 2014


ConferenceInformation Theory and Applications Workshop (ITA) 2014
Abbreviated titleITA 2014
CountryUnited States of America
CitySan Diego


  • Large-scale MIMO systems
  • local search
  • massive MIMO
  • message passing
  • spatial modulation

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