A Study of Random Access for Massive Machine-type Communications: Limitations and Solutions

Massive connection of machine-type communications devices is one of major issues for next-generation wireless communications technologies. In particular the contention-based random access method used in long-term evolution has many difficulties to support massive connection scenario of next-generation wireless communications technologies. This paper investigates the limitations in which the random access method currently used in cellular networks is difficult to apply to the massive connection scenario of the next-generation network. This paper firstly described the procedure of random access used in long-term evolution. This paper also describes the limitations of random access technology with respect to the collision probability and quality-of-service degradation due to retransmission. In addition, this paper introduces candidate solutions that can solve the described limitations of existing random access method and support massive connection requirements for the next-generation wireless communication technologies.