Balancing the Data Transmission and Random Access Phases in 6G mMTC Radio Technologies

Modern radio access technologies (RAT) for massive machine-to-machine communications (mMTC), such as LTE-M and NB-IoT, were designed with the assumption of a completely random and low traffic load from a single ED. Nowadays, new applications appear on the market such as smart grids that are characterized by much higher data transmission requirements. To develop new 6G RATs supporting forthcoming mMTC applications, there is a need to determine the optimal balance between the amount of resources allocated for the random access and the data transmission phases. In this letter, by utilizing the saturation principle, we propose a method for determining the optimal ratio of resources at these phases maximizing the system throughput. A critical observation is that the optimal resource balance maximizing the system throughput ensures delay performance which is just 5 - 10% off the optimal for a wide range of arrival intensities. The proposed approach can be used to design new 6G mMTC RATs with flexible frame design.