Browsing by Author "Shih, Ying-Ju"

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Design and Implementation of LTE RRM With Switched LWA Policies
(2018-02-01)
Lin, Yi-Bing
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Shih, Ying-Ju
;
Chao, Pei-Wen
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資訊工程學系
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Department of Computer Science
LTE-WLAN aggregation (LWA) combines the radio resources of LTE and WLAN, which takes the advantage of WiFi's high availability and indoor coverage to provide better usage of both WLAN and LTE. In this mechanism, it is essential that the network should intelligently switch a data radio bearer (DRB) to utilize either LTE or Wi-Fi. This paper implements the radio resource management layer (RRM) for LWA and proposes two types of the switched LWA policies: the guaranteed bandwidth and the equal sharing policies. We measure the delay times of the LWA procedures, which indicate that the switched LWA policies can be implemented at the RRM with negligible overhead. We conduct emulation, simulation, and analytic analysis to evaluate the performance of the switched LWA policies. The beauty of the LWA policies is that the performance is not affected by the DRB holding time distribution. Our study indicates that switched LWA can effectively reduce the blocking probability of the LWA's DRBs.
LWA Rate Adaption by Enhanced Event-Triggered Reporting
(2018-11-01)
Tin, Yi-Bing
;
Shih, Ying-Ju
;
Tseng, Hung-Chun
;
Chen, Ling Jyh
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資訊工程學系
Unlicensed spectrum has been utilized to open up additional capacity to support long-term evolution (LTE) service. LTE and wireless local area network (WLAN) Aggregation (LWA) is a perfect solution that satisfies this need. In 2017, Taiwan has deployed the first commercial LWA service. The deployed LWA network reuses and is nicely merged with the existing individual LTE and WLAN networks. To provide appropriate WLAN transmission bandwidth, the user equipment periodically measures the WLAN quality and reports the results to the eNB (the LTE base station). The eNB then decides if the transmission rate should be adapted. We investigate the performance of periodical reporting and then propose the enhanced event-triggered reporting to improve the performance of WLAN transmission rate adaption. We suggest how to select appropriate frequency to minimize the network traffic of periodical reporting. We also show that enhanced event-triggered reporting outperforms periodical reporting. Our solution utilizes the standard 3GPP protocols and does not modify the mobile phone's software.