## 3 Numerical Examples
The number of handovers in the proposed handover scheme increases as the ratio of high rate data traffic increases since more data traffic are managed by small cells and there are more handovers. If the ratio of high rate data traffic is very high, the number of handovers of the proposed handover scheme is higher than that of the CAC-based handovers due to frequent handovers since high rate data traffic is managed by small cells in the proposed handover scheme. In Figure 9, similar to the results in Figure 8, both CAC-based handover and the proposed handover have smaller number of handovers when handover minimization is applied than those when energy minimization is applied, respectively. From the aspect of total energy consumption, both CAC-based handover and the proposed handover have higher energy consumption for higher ratio of high rate data traffic since high rate data traffic consumes larger power than low rate data traffic. The proposed handover scheme has smaller total energy consumption than CAC-based handover since the proposed handover efficiently manages low rate data traffic and high rate data traffic in a macro cell and small cells, and can achieve more power saving. The energy saving is more significant if the ratio of high rate data traffic is lower since a UE with low speed and low rate data traffic can be managed by an always-on macro cell in the proposed handover scheme and thus results in more energy saving. Both CAC-based handover and the proposed handover have smaller total energy consumption when energy minimization is applied than those when handover minimization is applied. Figure 8: (**a**) Number of handovers for varying number of UEs in a macro cell; (**b**) Total energy consumption of BSs for varying number of UEs in a macro cell. Figure 10 shows the number of handovers and total energy consumption of BSs for varying the threshold of UEs speed. The number of handovers in both CAC-based handover and the proposed handover increases as the threshold of UEs speed increases since higher value of threshold of UEs speed results in more UEs managed by small cells in CAC-based handover and the proposed handover schemes. The proposed handover scheme has less number of handovers since a UE with low speed and low rate data traffic can be managed by a macro cell and results in the reduction of handovers. Both CAC-based handover and the proposed handover have a smaller number of handovers when handover minimization is applied than those when energy minimization is applied, respectively. From the aspect of total energy consumption, both CAC-based handover and the proposed handover have higher energy consumption for higher threshold of UEs speed since higher value of threshold of UEs speed results in more UEs managed by small cells in CAC-based handover and the proposed handover schemes and less small cells can be turned off. The proposed handover scheme has smaller total energy consumption than CAC-based handover since the proposed handover efficiently manages low rate data traffic and high rate data traffic in a macro cell and small cells, and can achieve  
Figure 10: (**a**) Number of handovers for varying threshold of UEs speed; (**b**) Total energy consumption of BSs for varying threshold of UEs speed. Figure 9: (**a**) Number of handovers for varying ratio of high rate data traffic; (**b**) Total energy consumption of BSs for varying ratio of high rate data traffic. more power saving. The energy saving is more significant if the ratio of high rate data traffic is higher since a UE with low speed and low rate data traffic can be managed by a always-on macro cell in the proposed handover scheme and the ratio of the UEs with low speed and low rate data traffic increases as the threshold of UEs speed increases. Both CAC-based handover and the proposed handover have smaller total energy consumption when energy minimization is applied than those when handover minimization is applied.