VoIP scheduling with reduced overhead and radio resource usage estimation-effect on best effort capacity

Abstract

In this work Dynamic and Semi-Persistent (SP) scheduling strategies and their capacity limits for Voice over IP (VoIP) with 1×2 antenna configuration in 3rd Generation Partnership Project (3GPP)-Long Term Evolution (LTE) network are presented. A method to reduce Channel Quality Indicator (CQI) feedback and Modulation and Coding Scheme (MCS) signaling for VoIP service has been proposed which not only saves a significant amount of overhead bits but also increases the capacity in terms of VoIP users. A model for predicting the effective radio resource usage(Physical Resource Block (PRB)s) for a given number of VoIP users, as a function of the Signal to Interference plus Noise Ratio (SINR) of the users is developed. This is useful in estimating the average number of available PRBs per Transmit Time Interval (TTI) when there is fractional VoIP load. The predicted numbers of available PRBs are closely matching with the results obtained from simulation. The model can be used to find the allowable Best Effort (BE) traffic throughput for mixed traffic scheduling during fractional VoIP load. The capacity region for mixed VoIP and BE services is also presented here.