LTE-U와 공존하는 적응적인 Wi-Fi 절전 모드

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 전기·정보공학부, 2019. 2. 최성현.LTE-Unlicensed (LTE-U) supports LTE downlink operation in 5~GHz unlicensed bands, where Wi-Fi has been a traditional incumbent for a long time. To achieve a fair coexistence with Wi-Fi, LTE-U employs carrier sense adaptive transmission (CSAT), but it does not guarantee a perfectly fair coexistence. Therefore, many studies have dealt with unfair coexistence problems of Wi-Fi and LTE-U. In this paper, our experiment results show that a Wi-Fi station not only suffers from unfair coexistence but also wastes energy and air time when it coexists with LTE-U. To cope with this problem, we propose AWARE, a station-driven adaptive Wi-Fi power save operation coexisting with LTE-U, which does not require any hardware modification. We implement AWARE on a commercial 802.11n device, and our evaluation shows that AWARE enhances throughput of Wi-Fi by up to 50% while reducing the power consumption of Wi-Fi station by up to 33% by effectively adapting Wi-Fi power state.LTE-Unlicensed(LTE-U)는 Wi-Fi가 오랫동안 사용하던 5~GHz 비면허 대역에서 LTE 하향링크 동작을 지원한다. 비면허 대역을 사용하는 Wi-Fi와의 공평한 공존을 하기 위해 LTE-U는 carrirer sense adaptive transmission(CSAT)을 이용하지만, 이는 공평한 공존을 완벽하게 보장하지 않는다. 따라서 많은 연구들은 Wi-Fi와 LTE-U의 불공평한 공존 문제를 다룬다. 본 논문에서, 우리는 실험을 통해 LTE-U와 공존하는 경우에 Wi-Fi 단말이 불공평한 공존 문제뿐만 아니라 에너지 낭비와 매체 점유 시간 낭비문제를 겪는다는 것을 확인했다. 이러한 문제를 해결하기 위해 우리는 AWARE를 제안한다. AWARE는 하드웨어의 수정없이 단말기에서 동작하는 적응적인 Wi-Fi 절전 동작이다. 우리는 상용 802.11n 장비에 AWARE를 구현하여 기존의 Wi-Fi와 성능을 비교하였다. AWARE를 통해 효과적으로 Wi-Fi 단말기의 파워 상태를 조절하여 Wi-Fi 단말기의 에너지가 약 33% 절약되었고 동시에 Wi-Fi 단말기의 수율이 약 50% 증가하였다.1. INTRODUCTION 2. RELATED WORK 3. PRELIMINARIES 3.1 LTE-Unlicensed (LTE-U) 3.2 Wi-Fi Power Save Mode (PSM) 3.2.1 Static PSM 3.2.2 Dynamic PSM 3.3 Automatic power save delivery (APSD) 4. MOTIVATION 4.1 Performance of Wi-Fi Coexisting with LTE-U 4.1.1 Scenario 1 4.1.2 Scenario 2 4.2 Energy and Air Time Waste Problem 5. AWARE: Proposed Algorithm 5.1 LTE-U Detection 5.1.1 Processing 5.1.2 Calibrating 5.2 Enhanced Power Save Operation (EPSO) 6. PERFORMANCE EVALUATION 6.1 LTE-U Detection 6.2 AWARE 6.2.1 Scenario 1 6.2.2 Scenario 2 6.2.3 Scenario 3 6.2.4 Scenario 4 7. CONCLUSIONMaste

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This paper described an analysis the different capabilities and limitation of both IEEE technologies that has been utilized for data transmission directed to mobile device. In this work, we have compared an IEEE 802.11/g/n outdoor environment to know what technology is better. the comparison consider on coverage area (mobility), through put and measuring the interferences. The work presented here is to help the researchers to select the best technology depending of their deploying case, and investigate the best variant for outdoor. The tool used is Iperf software which is to measure the data transmission performance of IEEE 802.11n and IEEE 802.11g

Performance analysis for wireless G (IEEE 802.11G) and wireless N (IEEE 802.11N) in outdoor environment

This paper described an analysis the different capabilities and limitation of both IEEE technologies that has been utilized for data transmission directed to mobile device. In this work, we have compared an IEEE 802.11/g/n outdoor environment to know what technology is better. The comparison consider on coverage area (mobility), throughput and measuring the interferences. The work presented here is to help the researchers to select the best technology depending of their deploying case, and investigate the best variant for outdoor. The tool used is Iperf software which is to measure the data transmission performance of IEEE 802.11n and IEEE 802.11g