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Mobile Videophone. Lauri Mäkinen April 26, 2007. Outline. Videophones in Fixed Networks Mobile Videophone Overview of Standards Operator Business User Perspective. Videophones in Fixed Networks (1). ”Just around the corner!” for 80 years. Videophones in Fixed Networks (2) - History.
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Mobile Videophone Lauri Mäkinen April 26, 2007
Outline • Videophones in Fixed Networks • Mobile Videophone • Overview of Standards • Operator Business • User Perspective
Videophones in Fixed Networks (1) ”Just around the corner!” for 80 years
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
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 (n2-n)/2 where n=number of users
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
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
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
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
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 (?)