Electronic Design

Move Over, Couch—The Cell Potato Is Here

From the fancy flatscreen to the mini-screen, movies and television will literally be at your fingertips.

It’s hard to keep up with today’s cell-phone functionality, with voice calls, text messaging, e-mail, Web surfing, GPS navigation, cameras, FM radios, and MP3 music. Now television has jumped headlong into the mix. A few carriers already offer TV programming over their networks, and new broadcast services have come online. Expect an even bigger push for mobile TV later this year and next year.

BIG CONTENT, LITTLE SCREENS
Nearly everyone watches their favorite programs and movies on a typical television screen, regardless of size or format. And broadband has more and more consumers checking out video on their computer monitors. So how can cell phones and their 1- and 2-in. screens hope to compete? Can you even read a movie’s credits on a handset? Probably not.

Even so, the viewing experience isn’t impossible. The screen’s tilt may present some problems, but new mobile TV content should be able to work around it. There’s also increasing demand for larger cell-phone screens. Look no further than the Apple iPhone, which is already establishing a trend with its 3.5-in. screen.

Do we need mobile TV? Did we ask for it? No and no. So why are we getting it? Because we can. More importantly, though, because it’s a new revenue source for carriers—and a new advertising outlet for sponsors. It won’t be for everyone, but many consumers will clamor for this “latest and greatest” technology.

It’s anybody’s guess on how many future cell phones will carry this capability. Most research firms see it as a very successful new handset venture, despite the lower-quality TV viewability.

HARDWARE/SOFTWARE ENABLERS
The technology and new broadband spectrum are driving mobile TV. Some mobile TV is available through the cell-phone networks, but it requires lots of high-speed data capability in the handset—a capability that’s already there. But if network mobile TV gets popular, the carriers will quickly run out of bandwidth and backhaul capacity. Potentially, this could hurt their ability to handle other broadband services like texting and e-mail, not to mention restricting expansion of their voice service. YouTube and Facebook already are taking their toll on cellular networks.

Thus, the move to broadcast mobile TV. A new network of broadcast stations in major markets will mainly supply cell-phone TV. These stations will send multiple channels of video to a separate receiver chip in the cell phone. With this setup, mobile TV can turn into a very successful reality. In fact, it’s already happening with services from both AT&T, called Mobile TV, and Verizon, known as V Cast.

So while the physical implementation problem has been solved, the greatest factor in its success will be content. Some existing TV shows, movies, and videos can be repurposed for mobile TV, but a whole new content industry is emerging. The goal is to create content especially for the small screen (see “Expected Mobile TV Content,” below).

Music videos should do well in mobile TV. But TV shows like sitcoms are too long, and movies even more so—a single film could spell the early death of a handset’s battery. Currently, the largest and most lucrative Internet video market is adult content. While such content for cell phones would be similarly successful, it’s doubtful the carriers would allow it. Besides, phones with Internet access could get that content anyway.

Video on demand (VOD) will be very desirable. So will podcasts, which could be used to provide educational content. Cell phones with mobile TV probably will have a flash-memory slot for pre-loaded content as well. Games may use video, but they won’t play a role in the mobile TV market.

So once you have your mobile TV, where and when will you watch it (see “Top 10 Places To Watch Cell-Phone TV,” p. 68)? Most of our viewing will likely take place when we’re in waiting mode, say at the train station or in the doctor’s lobby. But its convenience may tempt us to watch TV when we can least afford the distraction. How many people have you seen sending text messages while they drive? And mobile TV at work could hurt productivity more than the Internet and e-mail combined.

MOBILE TV TECHNOLOGY
Like any new wireless service, mobile TV is moving ahead quickly because of the currently available hardware and software, and multiple standards already exist. All of the standards use a coded orthogonal frequency-division multiplexing (OFDM) with quadrature phase-shift keying (QPSK) and quadrature amplitude modulation (QAM) as the basic modulation choices.

There doesn’t seem to be any method more spectrally efficient, especially with the robustness in a multipath environment with moving receivers. Also, all of the standards use the same video-compression method that provides a streaming data rate in the 256- to 300-kbit/s range.

The most common screen size, QVGA, has a basic pixel resolution of 320 by 240. Other sizes and formats are possible, but this is a good fit for screens in the 2- to 4-in. range with video rates of 256 to 300 kbits/s and a screen refresh rate of 15 or 30 frames/s. Other video formats supported include CIF (common intermediate format) with a 352- by 288-pixel count and a quarter-size version (QCIF) with a 176- by 144-pixel resolution.

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Of particular interest is the MediaFLO standard selected by AT&T, Verizon, and others for U.S. mobile TV. DVB-H was also widely considered, but not chosen for reasons unknown to this point. (The European Union did adopt DVB-H, though.) Old UHF TV channel 55 (716-722 MHz) will be used throughout the U.S. in all major cities with MediaFLO.

Qualcomm, which developed MediaFLO, recently acquired former UHF TV channels 53, 56, and 58 in the recent 700-MHz spectrum auction for additional capacity. Broadcast stations are expected to generate up to 50-kW effective radiated power (ERP) from antennas on towers 300 m high.

Most worldwide mobile TV will use one of these common standards. However, several other standards that are kicking around could see some action. S-DMB, a proprietary format from Toshiba in Japan, uses code-division modulation (CDM) in a 25-MHz bandwidth that can accommodate up to 20 channels.

Another standard, TDtv, employs the UMTS 3G technology TD-CDMA, which uses time-division duplexing rather than the frequency-division duplexing of the 3GPP’s WCDMA cell-phone standard. With 3GPP’s Release 6 Multimedia Broadcast Multicast Service (MBMS) standard, operators using 3G UMTS WCDMA can offer broadcast TV in an unpaired 5-MHz band. The 1900- and 2100- MHz bands are available worldwide for the standard. This overlay technology is a much lower-cost alternative for mobile TV. It also offloads the video network, keeping maximum capacity for voice and data.

There’s been some discussion of a mobile version of the Advanced Television Systems Committee (ATSC) HD and digital TV system in the U.S. It uses an MPEG-2 compressed video stream and 8VSB modulation rather than coded OFDM (COFDM). Last year, the ATSC solicited proposals for a mobile and handheld (M/H) version of this standard that can provide digital programming to portable and mobile units. Nokia, Qualcomm, Samsung with Rohde & Schwarz, LG Electronics with Harris, Thomson, and other major companies all submitted proposals.

Developed jointly by multiple members of the ATSC, Advanced VSB is a slower version of the HD ATSC protocol designed for mobile TV receivers to make cell-phone and portable TV devices possible. The MPH in-band mobile digital TV system developed by LG, Harris, and Zenith provides a low-bit-rate TV signal derived from the 19.39-Mbit/s signal used for fixed digital TV in the U.S.

MPH would permit current HDTV broadcasters to supply free overthe- air programming to mobile, pedestrian, and handheld devices in current 6-MHz channels. IC receivers designed for this standard, with slower video and smaller screens, would be needed. The main question is which carriers who control handset design will build-in A-ATSC receivers.

OBSTACLES TO ADOPTION
When it comes to adoption, integration shouldn’t be a problem. IC receivers are already available from sources like Analog Devices, Broadcom, DiBcom, Freescale, Frontier Silicon, Newport Media, Qualcomm, STMicroelectronics, and Texas Instruments. Critical engineering challenges do exist, though.

For instance, there’s trying to find space for the chip and the antenna. Even more daunting may be power consumption, as the chip and larger color screens will certainly eat more energy. A real challenge for ASTC mobile receivers will be the extra-long antennas needed for good reception. Remember early portable TV receivers like Sony’s Watchman and its long whip antenna?

Another issue is cost of service. All carriers will charge extra for TV. Fees in the $15 to $30 per month range are expected, but a structured system with a selectable number of channels may get adopted. There’s no doubt the TV service will be added onto any high-speed data plan.

The business model for carriers is critical. If they can’t make money, mobile TV won’t happen. So far, TV/video hasn’t been a success with carriers offering TV over the network. But with broadcast services beginning this year, and with content already out there, mobile TV is expected to take off. Still, good content will ultimately swing the “success” pendulum one way or the other.

Qualcomm’s subsidiary MediaFLO USA offers a group of channels for its services with AT&T and Verizon, including CBS Mobile, CBS College Sports, CBS News, Comedy Central, ESPN Mobile TV, Fox Mobile, Fox News, MTV, NBC News 2Go, NBC 2Go, CNBC, MSNBC, NickToons, and Nickelodeon. Both AT&T (Mobile TV) and Verizon (V Cast) use MediaFLO and offer these channels along with two or three special channels of their own to distinguish their services.

AT&T Mobile TV subscribers get Sony’s PIX movie channel and CNN Mobile Live. All MediaFLO services from both carriers are available in more than 50 major metropolitan areas. Currently, mobile TV handsets are available from LG, Motorola, and Samsung (Fig. 1).

Another challenge involves converting existing video material to a mobile format. Screen size and data rates as well as compression formats are different from fixed video methods and products. MediaExcel solved the problem with its hardware, which performs real-time conversion from one format to another (Fig. 2).

Mobile television will mean much more than just TV on a cell phone. Other portable devices will also be available. Perhaps a new version of the Sony Watchman is in the works. Backseat TV sets for cars will be available as well, such as the Sirius Satellite Radio Backseat TV now offered in some Chrysler vehicles.

See Associated Table 1
See Associated Table 2

TAGS: Mobile
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