Evaluation of QoS and QoE in Mobile WIMAX – Systematic Approach

Abstract

International standardization organizations, responsible for preparing specifications (such as IMT-Advanced) for emerging 4G networks, define requirements for system level simulations for the candidate technologies [1], [2]. The goal behind those documents is to facilitate System-Level-Simulations by providing common methodology to perform such simulations (i.e. for WiMAX). According to [1] cell-level simulations can be an intermediate step between Link and System-level simulation where the capacity of a single cell and a single Base Station, providing service for multiple users, is evaluated by means of comprehensive tests. Still the IEEE standardized simulation methodology [1] does not specify how to evaluate (WiMAX) system capacity with various connection admission control mechanisms. Therefore as a first step we focus on the problem of adjusting simulation methodology to facilitate simulations covering CAC with Time Division Multiplexing Access scheme (TDMA), OFDM and uplink traffic. The applied evaluation methodology is derived from the best-practices in IEEE 802.16m Evaluation Methodology Document and WiMAX Forum’s System-Level-Simulation (SLS) methodology. Afterward the introduced methodology is utilized to find answers to the following problems:  To what extent does the capacity change when different FEC codes are deployed (Convolutional Turbo Coding CTC, non binary Low-Density Parity-Check nbLDPC)  What is the user perception of the service quality (Quality of Experience QoE) and what are the differences in the system performance when different FEC codes are deployed?  How to improve resource estimation, especially when considering connection requests arriving in large batches?  How the performance of traffic – aware admission control algorithms changes, when some users follow VoIP traffic pattern with silence-suppression enabled?  Does the performance of measurement based CAC change, if the system experiences situations, in which connection requests arrive in large batches?