Calculation Method of Spectrum Requirement for IMT-2020 eMBB and URLLC With Puncturing Based on M/G/1 Priority Queuing Model

The major use cases for IMT-2020 include enhanced mobile broadband (eMBB) and ultra-reliable and low latency communication (URLLC). URLLC packets occur sporadically, but each time, available resources with favorable conditions are required for their timely and trusted transmissions. To this end, an overlapping scheme of puncturing a part of resources scheduled to an eMBB packet for URLLC packets is proposed. Such a scheme causes inevitable damages to eMBB packets. Thus, additional delays due to possible retransmissions of damaged packets should be considered in the calculation of spectrum requirement for IMT-2020. So far, the method provided by International Telecommunication Union Radiocommunication Sector (ITU-R) based on an M/G/1 non-preemptive priority queuing model has been widely used in calculating spectrum requirements for mobile broadband services. In this work, we extend it to reflect the puncturing of URLLC on eMBB. We fully consider additional delays due to retransmissions by exploiting the concept of delay cycle. Numerical simulations validate the accuracy of our analytical results. Furthermore, we provide an algorithm to calculate spectrum requirement for IMT-2020 using the same input parameters as in the method of ITU-R.