Massive Uncoordinated Multiple Access

The wireless landscape is poised to change, once again, within the next few years with the emergence of machine-driven communications, vehicular networks, cyber-physical systems, and other large-scale wireless networks, which are all important components of the Internet of Things (IoT) and 5G wireless systems. This new reality will impact the statistical profile of typical wireless traffic. Indeed, in addition to having individual users interact with personal phones or mobile computers, a sizable portion of wireless resources will be consumed by legions of unattended devices that seek to disseminate information in a random fashion. Currently deployed access schemes based on sustained connectivity, channel estimates and scheduling policies are ill-equipped to deal with data packets generated sporadically by myriad wireless agents. The overarching goal of this research initiative is to address this deficiency and devise access schemes for massive uncoordinated and sporadic multiple access, thereby readying the wireless infrastructures for the traffic of tomorrow.

This project will address this pressing need by generating randomized access strategies for massive uncoordinated and sporadic multiple access. Our efforts will be guided by two fundamental questions - i) How can one design good random access protocols (or joint MAC and physical layer schemes) for massive, uncoordinated wireless networks?, ii) What is the price to pay for the lack of coordination among active devices? These research directions are supported by our results which indicate that, in cases of interest, uncoordinated random access can be as throughput efficient and computationally efficient as coordinated schemes. We seek to leverage tools and powerful recent advances from information theory and coding theory such as physical layer network coding, codes on graphs, EXIT charts, message passing decoding etc for the design of novel multiple access paradigms and their analyses.

5G changing landscape figure taken from paper by Popovski et al, copyright belongs to IEEE


  • K. R. Narayanan and H.D. Pfister, Iterative Collision Resolution for Slotted ALOHA: An Optimal Uncoordinated Transmission Policy, in Proceedings of the International Symposium on Turbo Codes and Related Topics, August 2012 | pdf
  • S. Madala and K.R. Narayanan, Uncoordinated Rate Selection: Approaching the Capacity of Gaussian MAC without coordination, in Proceedings of ICC, Workshop on Massive Multiple Access, 2057-2062, June 2015 | pdf
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