Impact of Acknowledgments on Application Performance in 4G LTE Networks

Abstract

Fourth generation (4G) Long Term Evolution (LTE) is a new mobile phone network standard designed to provide both the capacity and Quality of Service (QoS) needed to support multimedia applications. Recent research in LTE has explored modifications to QoS setups, creating MAC layer schedulers and modifying the current QoS architecture. However, what has not been fully explored are the effects of LTE retransmission choices and capabilities on applications and quality of experience. This work examines the impact of LTE wireless acknowledgment modes and timer settings on Voice over IP (VoIP), file transfer and video streaming applications. Issues explored include interaction between application performance, network transport protocols, LTE acknowledgment mode, and wireless conditions. Network Simulator 3 simulations show that LTE retransmissions improve FTP throughput. With delay sensitive applications, such as VoIP and video, the benefits of LTE retransmissions are dependent on the loss rate and specific LTE settings. LTE providers should configure their networks to use retransmission policies appropriate for the type of application traffic.