Effects of QoS Scheduling Strategies on Performance of Mixed Services over LTE

3GPP is currently in the process of defining the long-term evolution (LTE) of 3G, which will be an all-IP network. Streamlining the system for packet services will lead to improvements in the form of higher bit-rates, lower latencies and a wider array of service offerings, but will also pose new challenges that need to be overcome. This paper investigates how call setup signaling will be affected as the load on the system increases and how the delivery of important signaling messages can be ensured. A traffic scenario where all users engage in both a voice over IP (VoIP) conversation and a video session is applied in an extensive network simulator. SIP signaling is used to set up the different media connections. We find that if all traffic is scheduled with equal priority, setup signaling might become heavily impaired and the delivery of signaling messages can not be ensured. However, if these messages are absolutely prioritized and always scheduled before other traffic, the length of call setups and terminations can be kept at almost constant values even if the system load is high. The results also indicate that other service qualities are not significantly affected by such a prioritization scheme.