Kyoung-Hak Jung

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While numerous efforts have been made to save energy of “client” devices but it has not been addressed for access points (APs) as they are assumed to be supported by AC power. This paper proposes E-MAP, which is an energy saving algorithm for a tethering smartphone that plays a role of mobile AP (MAP) temporarily. It saves MAP's energy by(More)
Delay Tolerant Networks (DTNs) provide message delivery services to users via intermittently connected nodes. In DTNs, routing is one of the most challenging issues since end-to-end connectivity between nodes may not be available most of the time. Although many routing protocols for DTNs have been proposed, they do not achieve satisfactory performance,(More)
Wifi tethering enables Wifi-only devices to access the Internet by sharing the WWAN (e.g., 3G and LTE) connection of a smartphone where there is no available Wifi access point. However, the current tethering schemes have a limitation as they consume a significant portion of the battery power for providing Wifi clients with the Internet connection. In this(More)
This paper proposes an energy-saving bit-rate adaptation algorithm for Software-defined Radio (SDR)-based wireless systems, called Joint Rate and Voltage Fallback (JRF). It exploits the unused network time in underutilized networks by using a lower bit-rate than what an underlying rate adaptation algorithm such as Auto-rate Fallback (ARF) or Robust Rate(More)
With the advancement and development for more than two decades, WiFi has become an indispensable infrastructure in most of indoor venues. Indoor localization using this pre-existing infrastructure has been studied in the literature and is proven practically feasible, which mostly relies on WiFi fingerprints and the corresponding radiomap database. Since the(More)
IEEE 802.15.4 has prominent advantages that are the low cost and low energy consumption. It is suitable to several energy critical applications suffered from limited resources. For this reason, many studies proposed energy-efficient solutions, however, they may waste energy caused by the frequent packet collisions since they do not consider the contentions(More)
WiFi interface is a significant contributor to battery draining on mobile device such as WiFi smartphone. Since distinguishing between unwanted packet and active packet is not feasible at MAC layer, the power management mechanism is equally affected by unwanted packets (packets with unreachable destination port). In this paper, we propose a probing and(More)
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