VoLTE Call Blocking Estimation in Cellular LTE Network

Abstract In recent years, Voice over LTE (VoLTE) has emerged as a significant technological solution for delivering voice services in wireless cellular networks. However, it’s often observed that call blocking occurs in Long Term Evolution (LTE) network when initiating new calls and during handoff procedures from one cell to another. New call requests may be blocked due to configuration failures, and handoff call failures can result from reconfiguration issues. These failures typically arise from the unavailability of radio resources. The availability of resources, specifically within LTE cells providing VoLTE service, vary depending on the combination of voice codecs and Modulation and Coding Scheme (MCS) used. This variability significantly impacts the call blocking performance of the LTE network, and requires further investigation. In this paper, we propose an analytical model based on Physical Resource Block (PRB)s utilizing Markov chain approach to reflect LTE scenarios delivering VoLTE service. Using this model, we estimate the VoLTE call blocking probability in the LTE network while considering different combinations of voice codecs and MCSs, as recommended by Third Generation Partnership Project (3GPP).