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Classification of N-Screen Services, Scenarios
and its Standardization
Changwoo Yoon, Hyunwoo Lee, Won Ryu*Electronics & Telecommunications Research Institute, Daejeon, Korea
cwyoon@etri.re.kr, hwlee@etri.re.kr, wlyu@etri.re.kr

Abstract— By the advent of IPTV and smart TV, the broadcasting is transmitted using Internet. Bi-directional programs are appeared onbroadcasting services. The convergence service combining with communication, information and web service are appeared too.
N-Screen service is a killer service of smart TV. It uses several terminals, either fixed or mobile, to provide bi-directional, convergenceand personal services with broadcasting service.
N-Screen service can be classified into three categories: first, OSMU (One Source Multi Use) case, providing same contents to terminals
having different capabilities such as screen size, CPU speed, memory, codec, network speed, etc. Second case is a vertical handover,continuous watching of content using different terminal. Third case is a collaborative service among multiple terminals. For example, acustomer is watching soap opera using TV, while watching a specific scene related information or advertisement using his PAD or smartphone.
In ITU-T SG13, the Y.sof (Service Scenario over FMC) was standardized. It defined detailed overall service scenarios using feature
extraction of seamless mobile convergence service on several networks such as WiFi, 3G, WiMAX/WiBro. This standard extracts key
features of five key elements: person, terminal, network, content, and service. Then, it analyzes relationships among key elements andsuggests overall service scenario model.
The service scenario model can be easily adopted on describing N-Screen service scenario because Y.sof handles scenario cases among
several fixed or mobile terminals.
In this paper, I will introduce Y.sof and classification of N-Screen service scenarios described using the standard. Also I will refer thestandardization issues of N-Screen and its technologies.
Keywords— IPTV, Smart TV, N-Screen, OSMU, FMC
Changwoo Yoon received the B.S. degree from Sogang University, Seoul, Korea, in 1990. He received M.S. degree from POSTECH,Pohang, Korea, in 1992. He received Ph.D. degree in Computer & Information Science & Engineering from University of Florida, US, in2005. Currently he is principal researcher and team leader in Virtual services platform team, ETRI and adjunct professor at UST. His
current research interests include N-Screen, IPTV, Cloud computing, SOA, Service creation/delivery technology and information retrieval.

Hyunwoo Lee received M.S. and Ph.D. degrees in 1995 and 2005, respectively, in Korea Aerospace University (KAU). He is currently aprincipal research engineer and team leader in convergence service networking research team, smart screen convergence research
department, ETRI. His main research interests include heterogeneous wireless access network, Mobile P2P, open IPTV platform in NGN.
His current research interests include cloud computing and platform.

Won Ryu, Ph.D received the BS degree in computer science and statistics from Pusan National University, Busan, South Korea, in 1983,
and the MS degree in computer science and statistics from Seoul National University, Seoul, South Korea, in 1987. He received his PhD
degree in information engineering from Sungkyunkwan University, Kyonggi, South Korea, in 2000. Since 1989, he has been a managing
director with the Smart screen convergence research department, ETRI, Daejeon, Korea. Currently, his research interests are IPTV, Smart
TV, IMT-advanced, and convergence services and networks and etc.