Browsing by Author "Wang, Li-Chang"

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eSES: Enhanced Simple Energy Saving for LTE HeNBs
(2017-11-01)
Lin, Yi-Bing
;
Wang, Li-Chang
;
Chen, Wei-Cheng
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資訊工程學系
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Department of Computer Science
This letter proposes enhanced simple energy saving (eSES), a simple yet novel scheme, that turns off the RF module of inactive low-power LTE Home evolved Node B (HeNBs), and accurately wakes up these dormant HeNBs when there are connection requests. The eSES does not modify the 3rd Generation Partnership Project (3GPP) specifications, and can co-exist with other HeNBs that do not exercise the eSES. We show that the eSES effectively saves the energy consumption of a dormant HeNB at the cost of moderately increasing the connection time of the first call request to the HeNB.
Performance of Splitting LTE-WLAN Aggregation
(2019-10-01)
Lin, Yi-Bing
;
Tseng, Hung-Chun
;
Wang, Li-Chang
;
Chen, Ling-Jyh
;
資訊工程學系
LTE-WLAN aggregation (LWA) combines the radio resources of LTE and WLAN to take advantage of Wi-Fi's high availability and indoor coverage, which provides better usage of both WLAN and LTE. In LWA, a user data radio bearer (DRB) is split if its packets are delivered through both LTE and Wi-Fi. For a split DRB, it is important to determine the LTE-to-WLAN ratio (LWR) or the ratio of packets delivered by LTE over WLAN. Based on WLAN's Received Signal Strength Indicator (RSSI), we propose a simple LWR selection rule. Using this rule, we describe a user plane implementation for LWA, where the adaptive LWA routing procedure can be easily implemented in the Radio Resource Management (RRM) and the Packet Data Convergence Protocol (PDCP) layer at the LTE eNB. In our implementation, the maximum LWA throughput is 99.14 percent of the optimal cases, and the packet loss rates are less than 0.0042 percent.
SES: A Novel Yet Simple Energy Saving Scheme for Small Cells
(2017-09-01)
Lin, Yi-Bing
;
Wang, Li-Chang
;
Lin, Phone
;
資訊工程學系
;
Department of Computer Science
Energy saving of small cells is an important issue for a mobile network deployed with a large number of small cells. These small cells are typically overlapped with macro cells. When the call traffic is light, a small cell enters the dormant mode to save energy. Therefore, its call traffic is directed to the overlapped macro cell. When the traffic load of the macro cell becomes heavy, the macro cell wakes up the dormant small cells to share the traffic load. It is a nontrivial task to wake up the "right" dormant cells. This paper proposes simple energy saving (SES), which is a simple yet novel scheme, to accurately wake up the dormant small cells. In a low-traffic environment, our scheme enables the small cells to quickly enter the dormant mode. When the macro cell is heavily loaded, it wakes up the dormant small cells to share its traffic load. Specifically, with 90% of energy saving in our scheme, a dormant small cell can be detected and reported to the macro cell in 1.3716 s. When the macro cell conducts the wakeup mechanism, with a probability of 0.9, more than 75% of the dormant small cells are not affected and can stay in the dormant mode. We also show that energy saving of the SES scheme is more effective when the macro cell covers a larger number of small cells.