An Energy-Efficient Coverage Algorithm for Macrocell—Small Cell Network Systems
Abstract
:1. Introduction
2. Related Work
3. Problem Description
3.1. System Model with Novel Configurations
3.2. Problem Formulation and Goal
- ;
- ;
- , ;
- , i = 1, 2, …, M.
4. Proposed Algorithm
- Service is provided at the starting point of user i in the SBS service state, and SBS service is also available at the end point.
- The path process has SBSs providing support overlay. In this case (SSS), service is provided using the corresponding SBSs in the path process. An example is shown in Figure 5a.
- The relay process does not have SBSs providing support overlay. However, the two SBSs that cover the starting and end points can be jointly used to provide relay process coverage after the adjustment of their power levels to , respectively. In this case (YNY), service is provided by these two cell-enlarged SBSs in the path process. An example is shown in Figure 5b.
- The relay process does not have SBSs providing support overlay, and the relay process coverage cannot be compensated by the starting and end point SBSs after the adjustment of their power levels to , respectively. In this case (XNX), service is provided by switching to the MBS in the path process. An example is shown in Figure 5c.
- Service is provided at the starting point of user i in the SBS service state, but SBS service is not available at the end point.
- The relay process has SBSs providing support overlay, and coverage can include the end point after adjusting the power level of the SBS closest to the end point to . In this case (SYN), the cell of this SBS is enlarged, and service is provided using the corresponding SBSs in the path process. An example is shown in Figure 6a.
- The relay process has SBSs providing support overlay, but coverage is unable to include the end point after adjusting the power level of the SBS closest to the end point to . In this case (SXN), the path process connection is switched to the MBS to provide service. An example is shown in Figure 6b.
- The relay process does not have SBSs providing support overlay. In this case (SNN), the path process connection is switched to the MBS to provide service. An example is shown in Figure 6c.
- Service is provided at the starting point of user i in the MBS service state, and SBS service is available at the end point.
- The relay process has SBSs providing support overlay, and coverage can include the starting point after adjusting the power level of the SBS closest to the starting point to . In this case (NYS), service is provided by transferring the original user-MBS connection at the starting point to this cell-enlarged SBS, with the corresponding SBSs being used in the remaining path process. An example is shown in Figure 7a.
- The relay process has SBSs providing support overlay, but coverage is unable to include the starting point after adjusting the power level of the SBS closest to the starting point to . In this case (NXS), service is provided by using the MBS in the path process. An example is shown in Figure 7b.
- The relay process does not have SBSs providing support overlay. In this case (NNS), service is provided by using the MBS in the path process. An example is shown in Figure 7c.
- Service is provided at the starting point of user i in the MBS service state, but SBS service is not available at the end point.
- The relay process has SBSs providing support overlay, and the starting and end points can be covered after adjusting the power levels of SBSs in the relay process closest to the two points to , respectively. In this case (NYN), the power levels of both SBSs are each adjusted to , and service is provided using the corresponding SBSs in the path process. An example is shown in Figure 8a.
- The relay process has SBSs providing support overlay, but the starting and end points cannot be covered after adjusting the power levels of SBSs closest to the two points to , respectively. In this case (NXN), service is provided by using the MBS in the path process. An example is shown in Figure 8b.
- The relay process does not have SBSs providing support overlay. In this case (NNN), service is provided by using the MBS in the path process. An example is shown in Figure 8c.
- The relay process has SBSs providing support overlay.
- There is at least one available SBS next to the coverage hole center (i.e., the coverage hole can be fully covered after adjusting the power level of any available SBS to ). In this case (SSD), the cell of the SBS closest to the coverage hole center is enlarged (note that such an SBS is denoted as SBStag to facilitate description later), and service is provided using the corresponding SBSs in the path process. An example is shown in Figure 9a.
- There is no available SBS next to the coverage hole center. In this case (SSO), the power level of the SBS deployed in the coverage hole center is set to (note that such an SBS is denoted as SBSh_tag to facilitate description later), and service is provided using the corresponding SBSs in the path process. An example is shown in Figure 9b.
- The relay process has no SBSs providing support overlay.
- There is at least one available SBS next to the coverage hole center. In this case, the cell of the SBS closest to the coverage hole center, which is denoted as SBStag, is enlarged.
- Together with SBStag, the coverage insufficiency in the relay process can be compensated after adjusting the starting point SBS power level to . In this case (YND), service is provided using these two cell-enlarged SBSs in the path process. An example is shown in Figure 10a.
- However, for the above power adjustment, the relay process cannot be compensated. In this case (XND), service is provided by transferring the connection to the MBS for the starting point and the relay process and by using SBStag for the end point. An example is shown in Figure 10b.
- There is no available SBS next to the coverage hole center. In this case, the power level of the SBS deployed in the coverage hole, which is denoted as SBSh_tag, is set to .
- Together with SBSh_tag, the coverage insufficiency in the relay process can be compensated after adjusting the starting point SBS power level to . In this case (YNO), service is provided using these two SBSs adjusted in the path process. An example is shown in Figure 11a.
- However, for the above power adjustment, the relay process cannot be compensated. In this case (XNO), the processing method is almost identical to that used in Case 2.B.a.ii; the only difference is that we use SBSh_tag for covering the end point. An example is shown in Figure 11b.
- The relay process has SBSs providing support overlay.
- There is at least one available SBS next to the coverage hole center. In this case, the cell of the SBS closest to the coverage hole center, which is denoted as SBStag, is enlarged.
- The starting point can be covered by the SBS in the relay process closest to the starting point after adjusting its power level to . In this case (NYD), service is provided by transferring the starting point connection to this cell-enlarged SBS, with the corresponding SBSs being used in the relay process, and SBStag being used at the end point. An example is shown in Figure 12a.
- However, for the above power adjustment, the starting point cannot be covered. In this case (NXD), the processing method is the same as the corresponding processing method in Case 2.B.a.ii. An example is shown in Figure 12b.
- There is no available SBS next to the coverage hole center. In this case, the power level of the SBS deployed in the coverage hole, which is denoted as SBSh_tag, is set to .
- The starting point can be covered by the SBS in the relay process closest to the starting point after adjusting its power level to . In this case (NYO), the processing method is almost identical to that used in Case 3.A.a.i; the only difference is that we use SBSh_tag for covering the end point. An example is shown in Figure 13a.
- However, for the above power adjustment, the starting point cannot be covered. In this case (NXO), the processing method is the same as the corresponding processing method in Case 2.B.b.ii. An example is shown in Figure 13b.
- The relay process has no SBSs providing support overlay.
- There is at least one available SBS next to the coverage hole center. In this case (NND), the processing method is identical to that used in Case 3.A.a.ii. An example is shown in Figure 14a.
- There is no available SBS next to the coverage hole center. In this case (NNO), the processing method is identical to that used in Case 3.A.b.ii. An example is shown in Figure 14b.
5. Results and Discussions
5.1. Parameter and Environment Settings
5.2. Effects of the Number of Users on the Various Performance Aspects
5.3. Effects of the Number of SBSs on the Various Performance Aspects
6. Conclusions
Acknowledgments
Conflicts of Interest
References
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Chung, Y.-L. An Energy-Efficient Coverage Algorithm for Macrocell—Small Cell Network Systems. Energies 2017, 10, 1319. https://doi.org/10.3390/en10091319
Chung Y-L. An Energy-Efficient Coverage Algorithm for Macrocell—Small Cell Network Systems. Energies. 2017; 10(9):1319. https://doi.org/10.3390/en10091319
Chicago/Turabian StyleChung, Yao-Liang. 2017. "An Energy-Efficient Coverage Algorithm for Macrocell—Small Cell Network Systems" Energies 10, no. 9: 1319. https://doi.org/10.3390/en10091319