A Study on Delay-Tolerant Voice Service in Mobile Network

摘要

Voice over Internet Protocol (VoIP) mainly includes Voice over LTE (VoLTE) Voice over Wi-Fi (VoWiFi) and Over-The-Top (OTT) Among VoLTE VoWiFi and OTT OTT voice service is more popular than the others because of its free calling fee Besides people prefer to use OTT service with Wi-Fi connection since most Wi-Fi is free to use otherwise using OTT with LTE connection is charged by the data transmission volume by the operator When people use OTT in a Wi-Fi intensive area it is possible that the UE may handover frequently between Wi-Fi and LTE However if the time period between when the UE handovers from Wi-Fi to LTE and when the UE handovers from LTE back to Wi-Fi is too short to transmit data the handover procedure from Wi-Fi to LTE can be considered unnecessary and power-consuming As a result this thesis proposes Delay-Handover-Algorithm (DHA) to avoid the unnecessary handover procedures by postponing the timing to handover from Wi-Fi to LTE This thesis also proposes an analytical model which is validated against the simulation model With the simulation experiments this thesis analyzes the performance evaluation of DHA and offers a guideline to configure the settings of DHA As a whole DHA can avoid the unnecessary handover procedures and cut down the using time within LTE

獎項日期	2018 8月 30
原文	English
監督員	Meng-Hsun Tsai (Supervisor)