## 2 An Optimized Handover Based on Context Information
### An Optimized Handover Scheme
\begin{table}
\begin{tabular}{c l} \hline \hline
**Value** & **Description** \\ \hline \(\text{B}_{\text{Mm}}\) & A macro cell BS m \\ \(\text{B}_{\text{Ss}}\) & A small cell BS s \\ \(\text{u}_{\text{k}}\) & A user equipment k \\ \(\text{w}_{\text{Mm}}\) & State of a macro cell \\ \(\text{w}_{\text{Ss}}\) & State of small cell \\ \(\text{a}_{\text{Mm},\text{k}}\) & Service state of \(\text{u}_{\text{k}}\) in a macro cell \\ \(\text{a}_{\text{Ss,k}}\) & Service state of \(\text{u}_{\text{k}}\) in a small cell \\ \(\text{d}_{\text{k}}\) & Existence of data service requested by \(\text{u}_{\text{k}}\) \\ \(r_{\text{k}}\) & Required data type by \(\text{u}_{\text{k}}\) \\ \(\text{r}_{\text{k}}\) & Speed of \(\text{u}_{\text{k}}\) \\ D\_Cell\_based\_input\_net\_k, k & Traffic load of a target cell \\ \(\text{B}_{\text{target\_m},k}\) & A target macro cell BS m of a UE k \\ \(\text{B}_{\text{target\_s},k}\) & A target small cell BS s of a UEk \\ \(\text{B}_{\text{per\_m},k}\) & A serving macro cell BS m of a UE k \\ \(\text{B}_{\text{per\_s},k}\) & A serving small cell BS s of a UE k \\ \(\text{B}_{\text{per\_s},k}\) & A set of available macro cell BS m \\ \(\text{B}_{\text{avail\_sm}}\) & A set of available small cell BS s \\ \(\text{P}_{\text{max}}^{\text{max}}\) & Maximum power consumption in macro cell with on state \\ \(\text{P}_{\text{Small}}^{\text{max}}\) & Maximum power consumption in small cell with on state \\ \(\text{P}_{\text{Small}}^{\text{static}}\) & Static power consumption in macro cell with on state \\ \(\text{M}_{\text{Moro}}\) & Static power consumption in macro cell with on state \\ \(\text{P}_{\text{Small}}\) & Static power consumption in small cell with on state \\ \(\text{P}_{\text{Marco\_linear}}\) & Slope of power consumption in macro cell to transmit UE data \\ \(\text{P}_{\text{Small\_linear}}\) & Slope of power consumption in small cell to transmit UE data \\ \(\text{P}_{\text{Marco\_total}}\) & Total power consumption of a macro cell \\ \(\text{P}_{\text{Small\_total}}\) & Total power consumption of a small cell \\ \(\text{P}(\text{Ss})\) & Total power consumption of s-th small cells \\ \(\text{P}_{\text{total}}\) & Total power consumption of BSs \\ \(\text{u}_{\text{Mm\_served}}\) & A set of served UEs by \(\text{BS}_{\text{Mm}}\) \\ \(\text{u}_{\text{Ss, served}}\) & A set of served UEs by \(\text{BS}_{\text{Ss}}\) \\ \(\text{RSRP}_{\text{Bar\_m},\text{k}}\) & Reference signal received power of \(\text{BS}_{\text{ever\_m},\text{k}}\) \\ \(\text{RSRP}_{\text{Bar\_s},\text{k}}\) & Reference signal received power of \(\text{BS}_{\text{ever\_s},\text{k}}\) \\ \(\text{C}_{\text{R}_{\text{target\_s},\text{k}}}\) & Condition of Admission control level \\ \(\text{C}_{\text{Total capacity of a cell}}\) & Total capacity of a cell \\ \(\text{C}_{\text{Marco}}^{\text{max}}\) & Total capacity of a macro cell \\ \(\text{C}_{\text{Small}}^{\text{static}}\) & Total capacity of a small cell \\ \(\text{C}^{\text{*}}\) & Actual capacity needed for an active user \\ \(\text{C}_{\text{req}}\) & Requested capacity by a handover call \\ \(\text{C}_{\text{req,high}}\) & Requested capacity by a handover call having high rate data service \\ \(\text{C}_{\text{req,low}}\) & Requested capacity by a handover call having low rate data service \\ \(\text{No\_U}_{\text{High\_rate}}\) & Number of users requiring high rate data service \\ \(\text{No\_U}_{\text{Elow\_rate}}\) & Number of users requiring low rate data service \\ \(\text{TH}_{\text{HO}}\) & Percentage of cell capacity reserved for handover calls \\ L\_threshold & Threshold of supposing cell has low traffic loads \\ V\_threshold & Threshold of user speed having high and low speed \\ HO\({}_{\text{case}}\) & The case of commuting handover \\ HO\({}_{\text{total}}\) & Total number of handovers \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Notations. Figure 4 shows the flowchart of the proposed handover. A UE checks the RSRP of a serving cell and compares it with a threshold value.