Effect of handover on the performance of scheduling algorithms in LTE networks

In this work, using ns-3 and different mobility models, we simulate realistic LTE network scenarios to study the effect of handover on two popular schedulers, namely the Proportional Fair (PF) and Max Weight (MW) scheduler. The performances of these schedulers are widely studied in the literature via simulation and mathematical analysis in the absence of handovers. Specifically, it has been shown that MW is throughput optimal among all scheduling policies that stabilize the system in the sense of bounding the user queues. In our experiments, however, we observe that such general conclusions may not be accurate in the presence of mobile users that hand over across multiple cells. To this end, we show that: i) MW achieves higher throughput than PF when users are confined to a single cell, but ii) when there is handover in the network across multiple cells, PF achieves a throughput similar to that of MW, and in some cases even slightly outperforms MW. Furthermore, these observations are consistent across a wide range of network scenarios in terms of round-trip delay, buffer size and channel fading.