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Mobile Videophone Lauri Mäkinen April 26, 2007
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Outline Videophones in Fixed Networks Mobile Videophone Overview of Standards Operator Business User Perspective
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Videophones in Fixed Networks (1) ”Just around the corner!” for 80 years
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Videophones in Fixed Networks (2) - History Video calling booths (1960s) Booked in advance $16 for a 3 minute call Desktop videophones (1960s-1970s) Picturephones I & II $13.50 / minute (long distance, 10 times a regular voice call) Videoconferencing (1970s-1980s) Rentable rooms at $2340 per hour Initial cost of $117 500 to own a room Videophones for the masses (1980s-1990s) Japanese enter the market Regular phonelines Employed video compression Cost no more than regular voice call
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Videophones in Fixed Networks (3) - Reasons for failure Ahead of its time Too expensive Technology-centric (advanced features) Early videophones required several regular phonelines No consumer need Although market research showed huge interest Low quality Standalone-technology Network effect Metcalfe’s law: value of a networked service is proportinal to (n 2 -n)/2 where n=number of users
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Mobile Videophone Technically very different than any other type of video service Requires: Very low latency Synchronicity To meet these requirements Efficient but computationally light compression/decompression Circuit switched data transfer
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The standard - 3G-324M Modified version of H.324 (the standard for modem based video telephony) Added error resilience by enforcing some optional features of H.324 Main parts: H.223 – Multiplexing of different media types (voice, video, data) Several levels, each adding error resilience H.245 – Call control Handles non telephone related call controls Logic channel signalling, mode request, capability exchange Video codecs H.263 – Mandatory (considered legacy) Doesn’t handle error prone bearer too well MPEG-4 Visual codec (simple profile at level 0) – Recommended Provides error resilience and cocealment
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3G-324M – Architecture Overview
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Use Perspective Purpose – sharing experiences and emotions ”See-Me” ”See-What-I-See” – thanks to mobility Used with people close to you Downsides Less discrete than pure voice Uncomfortable pose Increased cognitive load Sometimes people just don’t want show their faces
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Operator Business Helps to drive the adoption of 3G networks and services Finnish operators offer video calls by default to all 3G customers No opening fee Charged by use Example of deployment Saunalahti – first in Finland (Janury 2005) Price around 0.20€ / minute
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Success Factors Interoperability The 3G-324M standard embraced by both 3GPP (UTMS) and 3GPP2 (CDMA2000) Interoperable with VoIP by using gateways Helps reduce network effect Not a standalone product Videotelephony is a part of the 3G offering Synergy: 3G-324M used for mobile TV Easy to use Doesn’t require any setup Reasonably priced Quality of Service satisfactory (?)
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Conclusions - SWOT Strengths one standard embraced by all interoperability satisfactory quality Weaknesses satisfactory quality awkward user experience Opportunities ever increasing bandwidth videoconferencing becoming commonplace declining popularity of flight travel Threats the network effect no real use need price competition
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