Investigating the Impacts of IP Transport Impairments on VoIP service in LTE Networks

Abstract:
Mobile network operators (MNOs) need agreements with ISPs (IP Service Providers) on the quality of IP transport networks for LTE. Owning to the fact that requirements on QoS parameters drives the bandwidth leasing costs, MNOs have great interest in defining minimum requirements of transport network QoS parameters which can still meet target QoE of the end users. This work is focused on defining such QoS parameter requirements for VoIP applications based on narrowband and wideband codec. Through an intensive set of simulations we investigate the impact on VoIP call quality caused by transport network impairments. VoIP call quality is evaluated by implementing procedures recommended by ITU-T standards into LTE system level simulator developed in OPNET. We find that user QoE of VoIP is more sensitive to packet loss than to packet delay impairments for the investigated IP network profiles. Moreover user QoE can be enhanced using wideband codec. Further investigations are encouraged to include more wideband codec and study of handover procedures in greater detail.