by Christine Perey & Arnold Englander
February 11, 2004

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If you were buried under projects this past year and not paying attention to the industry, you might have missed the fact that streaming media is finally reaching beyond PCs and set top boxes to mobile hand sets. In 2004, mobile phone service subscribers around the world are signing up for and experimenting with new, enhanced services featuring synchronized audio and video. The first mobile rich media application to launch is video messaging, since it is a straightforward evolution of photo messaging and immediately appeals to target audiences' need to communicate personal information. Access to streaming media archives of news and sports content is also compelling to many mobile phone users.

The evolution of mobile streaming media services is a direct function of what network operators call "generations" of technology. First generation (1G) mobile networks (through the 1980s) were analog, designed to carry voice and voice-call signaling. Unlike the Internet, which is fundamentally a shared resource, their architecture was circuit-switched (like the traditional public fixed-line telephone network); for the duration of a call, two parties are the exclusive users of their particular connection (or "call path") through the network. When their call is completed and they hang up, the call path is torn down and the network resources (e.g. connections and switch ports) can be re-assigned to the next users. The second generation (2G) mobile networks deployed in the 1990s are digital but still circuit switched and began only carrying voice and voice-call signaling. Eventually data services were deployed over 2G networks, but using circuit-switched data paths at bit-rates of 14.4kbps—much like early modems over the traditional fixed line telephone networks. Given the low data communications bandwidth and circuit-switched architecture of 2G networks, video streaming to mobile phones had trouble getting off the ground. For the same reasons, other less demanding forms of data communications (e.g. Internet access, email, or data downloads) also languished behind mobile network operators' targets.

Between 1998 and 2002, as the demand for all kinds of data communications over mobile phones and mobile PCMCIA cards grew, operators upgraded their networks to two-and-half generation (2.5G) technology. These networks move data communications off the circuit-switched side of the network to a purely IP-based data platform that uses technology similar to (and integrates nicely with) the Internet. The increased bandwidth and new application flexibility offered on the new platform create opportunities for developers of streaming media systems to leverage their core technologies to enable what we see emerging today.

The dominant 2.5G network technology is GSM-GPRS (Global System for Mobile communications-General Packet Radio Service). GPRS is theoretically capable of just over 100kpbs, but more realistically delivers a consistent overall average of 30kbps. Even faster 3G networks (theoretically promising 384Kbps to 1Mbps) are already being built and some 3G services have been launched. But 2.5G is proving to be more than adequate to get mobile video streaming and messaging into the market, largely using extensions of current Internet streaming media technology.

In contrast with content prepared for PC monitors, the content streamed to mobile users is much smaller. Screen sizes vary from 128 x 160 pixels to 208 x 320 pixels and color depth varies from 12-bit (4096 colors) to 16-bit (over 65,000 colors), depending on the handset manufacturer and model. Over GSM-GPRS mobile networks, streams start playing five to 10 seconds after the mobile user’s click and frame rates range from four to eight frames per second.

Mobile Streaming Versus Messaging
In general, mobile streaming media experiences are brief. The main difference between mobile streaming and messaging is that with streaming, the media begins playing quickly after a user request. The content streamed from the server is typically commercially prepared. Since the files are not stored in the user’s handset, all kinds of intellectual property/copyright and handset design issues are skirted.

According to Dror Zelber, product manager at Emblaze Systems, the two most promising usage paradigms for video streaming are portals (where users browse and select clips they want to watch), and "push engines" (where a server automatically sends subscribers alerting messages when new mobile-ready content fitting their preference profile and/or whereabouts becomes available). Mobile streaming video portals are commercially deployed today and push engines will be available in the near future. Depending upon service provider and service plan, prices for streaming media clips typically range from $0.25 to $1.00 for a half-minute clip, to on "all-you-can-watch" package ranging from $5 to $15 per month.

In addition to Emblaze, RealNetworks and PacketVideo are very active in this market. For example, subscribers of RealOne for mMode, a new service combining RealNetworks’ technology and expertise with AT&T Wireless service, have access to hours of content, including frequently refreshed news and business updates, entertainment, sports, and weather. PacketVideo is differentiating itself as a "mobilemedia" technology provider focusing on the delivery of MPEG-4-based, embedded software for advanced mobile handsets and solutions for mobile network operators.

In contrast with mobile streaming of canned content, mobile video messaging involves capturing, uploading, and downloading entire clips as files, and sending them to other users on PCs or mobile handsets as Multimedia Messages (MMS), similar to a photo and sound clip. Applications for mobile video messaging are expected to include personal video greeting cards, mini-press interviews, and newsreels, on-the-ground video reports from service technicians in the field and executives’ directives to their subordinates.

To record a clip, mobile camera-phones are morphing into mobile camcorder phones, including a built-in 640 x 480 pixel color camera capable of capturing media to the handset’s memory. Clips range from a few seconds to a few minutes long, consuming somewhere between a few hundred Kilobytes and a few Megabytes of memory. Downloading or uploading a video message typically takes a half-minute to a few minutes on a 2.5G GSM-GPRS network and pricing is similar to streaming service rates cited previously.

Growth Expectations and Early Deployments
No matter how you count it, streaming to mobile phones is big business. Ovum senior analyst Dario Betti predicts that video messaging will generate $650 million in worldwide service revenues in 2005. But Betti adds, "Mobile video will really take-off in 2007 and 2008. By then one in four users will be sending video messages." By 2007, this could be one in four of over a billion subscribers of next-generation mobile services worldwide. Using its model, Strategy Analytics estimates that by 2008, over 150 million users worldwide will be wirelessly accessing video clips (including sports, movies, and adult entertainment), generating revenues of just under $4.7 billion.

Shawn Ambwani, executive vice president of marketing and business development for Nextreaming, a provider of MPEG-4 solutions to the mobile streaming media market, summarizes the opportunity on behalf of many vendors investing in this market. "Video is going to be a natural part of the mobile space as it evolves from voice, to multimedia messaging including still photography, to video messaging, to videoconferencing."

Service providers are also counting on growth of mobile streaming video and video messaging services. According to Mauro Sentinelli, managing director of Telecom Italia Mobile, active data users generate four to five times more revenues for the service provider than a voice-only subscriber. MMS subscribers are spending about 8 times more than a voice-only subscriber. With MMS still being predominantly photos and sound clips, it’s easy to imagine how video messages will drive MMS revenues even higher. Some of the prominent mobile operators that have deployed streaming media services include AT&T Wireless, O2 in the U.K., Optimus in Portugal, Hutchison 3G in Austria and the U.K., WIND in Italy, Orange in Switzerland, Telstra in Australia, Vodafone in the U.K., Germany and Australia, and MobileOne of Singapore among others.

Challenges
Initially mobile video was an attractive way for mobile operators to recoup their investments in 2.5G infrastructure. With the exception of a few operators such as Hutchison 3G, who have already deployed mobile video over UTMS networks, most of the mobile service providers offering video have launched their services using underutilized 2.5G networks. But the utilization of the data capabilities of 2.5G networks is growing fast from Internet access, MMS photos, downloads of ringtones, icons, and other mobile multimedia treats. As 2.5G networks start to get heavily used, the Quality of Experience (QoE) for mobile video will degrade unless operators respond with more investment. Upgrading networks to 2.75G (e.g. GSM-EDGE) technology will help by doubling (or, in some cases, tripling) the available bandwidth per user. However, many argue that 2.75G hardly begins to address the real challenges facing mobile video as its adoption grows.

For mobile video to reach its potential, operators will need to maintain the quality of user experience as subscriber numbers rise. Subscriber satisfaction with video and audio quality depends on reasonably steady flows of sizable chunks of data to the user’s handset. Degradation of experience due to delays introduced by the mobile network congestion and bandwidth fluctuations need to be avoided. Artifacts and stream interruptions during play back are unacceptable. Further, in the case of video messaging, when downloading or uploading a clip takes 2x, 5x, or 10x longer than the length of the experience, subscribers get impatient.

Networks must provide subscribers with congestion-free service. One way to address congestion as subscriber numbers rise is to build bigger, denser cellular networks so that that they are effectively over-provisioned and underutilized. But this makes an extremely unattractive business case for mobile operators.

CellGlide’s Mobile Traffic Shaping solutions offer one approach to the problem. "Over-building infrastructure helps avoid the congestion," explains Eran Barak, director of corporate development at CellGlide, "but a platform that manages packet priorities can deliver the right subscriber experience and economic value from streaming, as well as other business applications of mobile data that require Service Level Agreements." CellGlide equipment monitors and tracks the requests for data services from users across collections of cells, and according to various priorities, can delay, throttle, or block these requests. In the process, Cellglide technology also reduces redundant requests and data transmissions. Prioritization can be based on the application (e.g. streaming video over email), the service plan (e.g. the premium plan over the value plan), or even the end-user (e.g. Warren Buffet or Donald Trump over the "low revenue" subscriber).

Others in the mobile video industry believe that for video streaming (if not video messaging), and certainly for videotelephony, the appropriate quality of service will only be met by moving the video and audio over to the switched-circuit side of the mobile network. The switched-circuit side of 2.5 and 3G networks provides low latency, relatively evenly-flowing transmissions, and seemingly dedicated connections that are less subject to choking by some other multimedia-imbibing user wandering into the cell.

Looking Ahead
When asked, several technology and infrastructure vendors say mobile videotelephony is the next frontier. But for RADVISION customers, videotelephony is already a reality. "Mobile videotelephony has been deployed in by NTT-DoCoMo’s (the world’s largest mobile service provider) network for two-and-a half years," points out Eli Doron, RADVSION’s chief technology officer. "They currently have 2 million subscribers, and all their new phones are videotelephony capable. Hutchison 3G is deploying these services around the world as well. During 2004, we will see another ten or so operators launch video telephone services, and in 2005 most of the rest will join."

Gareth Jones, chief operating officer of 3UK (the brand name for Hutchison 3G UK Limited) agrees. "International video calling is here," assures Jones. "Making a video call is as easy as making a normal phone call from your mobile, but they have much more impact, as you can see the person with whom you’re speaking. As a means of keeping in touch, international video calling allows you to see how friends and family are doing. Or maybe you have work contacts that you’ve never met. A video call will allow you to meet them for the first time." And, at typical international videotelephony calling rates in the neighborhood of $2.00 per minute, one can understand why service providers are as excited as the technologists, equipment vendors, and early adopters. Visionaries are confident that the end-user value is there as well. As Nextreaming’s Shawn Ambwani sums it up, mobile videoconferencing and videotelephony will be the natural evolution of video messaging and streaming media. "People want to be more closely connected," Ambwani states, "both in their in personal and business lives. Business is about people and levels of trust. Seeing people improves levels of trust and so mobile video helps get more business done."

Nonetheless the mobile videotelephony technology to which Eli Doron is referring, GSM-H.324M, necessarily builds on 3G mobile network technologies (W-CDMA in the case of work RADVISION is doing with NTT-DoCoMo). The opportunity to combine video telephony and streaming media in new and seamless ways will eventually drive service providers to advance their networks yet one more generation.