Research Interests Wireless Communication Networks/Systems  - Wireless PAN/LAN/MAN (WPAN/WLAN/WMAN)  - Mobile WiMax (WiBro)  - LTE, LTE-A  - Cognitive Radio Networks  - Sensor/Ad-hoc/RFID Networks  - Mesh Networks Research Interests Internet/Home Networks  - TCP/IP, Mobile IP  - Network Mobility (NEMO)  - HomePNA, HomePlug Optical Networks  - WDM Networks  - EPON, WPON Research Field  - Medium Access Control (MAC)  - Resource/Bandwidth Allocation  - Crosslayer Design  - Cooperative Communications  - Fractional Frequency Reuse (FFR)  - Scheduling/Polling/Routing/Hand-off  - Power Control/Mobility Project "High-Speed/Reliability Monitor/Tracking Mechanism in RFID Systems with Moving Tags," 한국과학재단(Ministry of Education Science and Technology), 2009.05 - 2011.04 "Wireless Cooperative Communications," ITRC, 정보통신연구진흥원(Ministry of Knowledge Economy), 2008.7 - 2011.12 "Integrated Wired/Wireless Networks Supporting Femto-zone," 학술진흥재단(Ministry of Education Science and Technology), 2008.7 - 2009.6 "Center for Advanced IT HRD with Close Industry Cooperation," BK21 교육인적자원부(Ministry of Education & Human Resource Development), 2006.3 - 2013.2 "Increasing Capacity of Cognitive Radio Networks by Spectrum Trading," 삼성전자(종합기술원) (Samsung Electronics (SAIT)), 2007.5 - 2007.12 "Collision Resolution and Identification of RFID Tags under Unreliable Channel," 학술진흥재단(Ministry of Education & Human Resource Development), 2006.11 - 2007.10 "Fractional Frequency Reuse for WiBro Evolution," 삼성전자(종합기술원) (Samsung Electronics (SAIT)), 2006.8 - 2006.12 "Multi-Homed Network Mobility (NEMO) in Mobile Networks," 과학재단(Ministry of Science and Technology), 2006.3 - 2009.2 "Resource Allocation of PON Systems with WDM Networks," 정보통신연구진흥원(Ministry of Information and Communication), 2005.12 - 2006.11 "Design and Performance Evaluation of Tactical Mobile Ad-hoc Networks," 삼성탈레스(Samsung Thales), 2005.8 - 2005.10 "Power-efficient MAC in Next Generation Wireless LAN," 삼성전자(종합기술원) (Samsung Electronics (SAIT)), 2004.11 - 2005.10 "Design of Internetwork Communications and Security in High-rate Wireless PAN," KETI, 2005.1 - 2005.11 "Efficient MAC for Nomadic Wireless Systems," 삼성전자(종합기술원)(Samsung Electronics (SAIT)), 2003.11 - 2004.10 "High-Quality and HIgh-Reliability Lambda-Networking," 정보통신연구진흥원(Ministry of Information and Communication), 2004.6 - 2006.6 "Power Management and QoS Enhancement of High-rate Wireless PAN," KETI, 2004.1 - 2004.11 "Resource Management in Wireless LAN," 삼성전자(종합기술원)(Samsung Electronics (SAIT)), 2002.10 - 2003.9 "Next-Generation Wireless PAN," 삼성전자(종합기술원)(Samsung Electronics (SAIT)), 2001.10 - 2002.9 "Scatternet Scheduling in Bluetooth," 정보통신연구진흥원(Ministry of Information and Communication), 2002.7 - 2004.6 "Protection and Restoration in Optical Networks," 학술진흥재단(Ministry of Education & Human Resource Development), 2002.7 - 2003.6 "Mobile Healthcare System (Sensor Networks)," 경기도무선인터넷센터, 2003.8 - 2006.7