Estimation of Effective Radio Resource Usage for VoIP Scheduling in OFDMA Cellular Networks

This work presents a method to estimate the amount of radio resource required to support a given number of Voice Over IP (VoIP) users in Orthogonal Frequency Division Multiple Access (OFDMA) based cellular systems. The proposed method is useful for the Call Admission Control (CAC) module, which needs to estimate the radio resource utilization before admitting new calls in the system. It is also useful in predicting the maximum number of VoIP users that can be supported for different cell scenarios and spatial user distributions. The proposed method is evaluated for Dynamic as well as Semi-Persistent (SP) scheduling algorithms. Results are presented for 1×2 Maximum Ratio Combining (MRC) and 4×2 Space Frequency Block Code (SFBC)- Frequency Switched Time Diversity (FSTD) modes. The 3^rd Generation Partnership Project (3GPP)-Long Term Evolution (LTE) system parameters are used for performance analysis in this work.