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Joint Design of Coded Tandem Spreading Multiple Access and Coded Slotted ALOHA for Massive Machine-type Communications

In industrial internet of things (IIoT), massive machine-type communications (mMTC) system is introduced to provide communication services for large-scale industrial devices. To achieve massive access with scarce radio resources in mMTC, multiple access protocol has to be reconsidered to cope with the resulting collision problem. Currently, various novel multiple access schemes have been proposed. Among them, coded tandem spreading multiple access (CTSMA) is an emerging physical (PHY) layer multiple access scheme to resolve the collision in mMTC. In this paper, a multislot design scheme of CTSMA is proposed to further promote the collision resolution capability. In this scheme, CTSMA is combined with the MAC layer scheme coded slotted ALOHA (CSA). The analysis shows that the multislot design can effectively take advantage of CTSMA and CSA to enhance the mMTC system performance for the short uplink contention period, which is suitable for the IIoT applications.