Small screen, big challenge

The recent Ukraine versus England football match streamed over the internet was a landmark broadcast, but only because it was not shown on domestic tv. The event highlighted how broadcast entertainment no longer needs a tv to reach a mass audience. Yet delivering tv to the most ubiquitous consumer device of all – the mobile handset – continues to be a struggle. In Japan and South Korea, mobile tv has been widely adopted. According to ABI Research, 40million handsets in Japan alone – 90% of mobile users – receive mobile tv. But the service is known as free to air – tv broadcasts are received by handsets and laptops equipped with receiver and decode hardware. Mobile operators support the service, but they don't get paid for it. "Mobile tv generically is broadcast tv," said Kent Walker, vice president of technology at Qualcomm, "although how it gets there is not crucial." For example, content could be sent over the internet or a 3G cellular network – unicast networks that deliver unique content to the user. Mobile tv also implies tv on your phone, says Walker. "There are other markets emerging [laptops, netbooks], but it's dominated by handsets." Ronen Jashek, vp of marketing at mobile tv chip firm Siano Mobile Silicon agrees that mobile tv is a vaguely defined term. But he stresses it implies broadcasting. "It's a real time tv service that is high quality and high bit rate – at least 384kbit/s," said Jashek. "It can only happen with broadcast technology, not with 3G, 3.5G networks and maybe not 4G." Mark Heath, analyst and cofounder of Unwired Insight, believes there is a disconnect between what the industry regards as mobile tv and what end users want. He argues the industry equates mobile tv with broadcast standards delivering tv content, whereas users want to watch video when they choose. "For the industry, mobile tv is the thing that delivers it, it's not about video and time shifted video," says Heath. "This is absolutely wrong." Jeff Orr, senior analyst, mobile devices, at ABI Research, highlights other challenges facing mobile tv. "There is a lack of a global standard – even a major regional standard," he said. Indeed, there are more than six mobile tv standards in use worldwide. In Europe, and parts of South East Asia and Latin America, Digital Video Broadcasting – Terrestrial (DVB-T) is used, while the handheld variant DVB-H has been adopted sporadically in Europe, as well as in South East Asia and South Africa. The ISDB-T standard is used in Japan, while South Korea uses T-DMB. And in the US, Qualcomm's MediaFlo is used, as well as ATSC (similar to DVB-T). Meanwile, a mobile variant dubbed ATSC-M/H is set to appear in 2010. On top of this, China has added its own standard: CMMB. "Almost every 3G phone sold by China Mobile will support CMMB," said Jashek and Siano has developed a CMMB device solely for the Chinese market. Europe at least had the foresight to adopt DVB-H, but even here there is a question as to whether DVB-H will work in different countries, said Orr. Moreover, regulatory and spectrum license issues have meant the vision of widespread adoption of DVB-H in Europe has not happened. "Such [multistandard] fragmentation has not helped motivate advertisers and has meant that prices are artificially high," said Orr. The business case for mobile tv also remains unproven. Mobile tv requires operators to install a parallel infrastructure alongside their cellular networks which is costly. In contrast, using a 3G network for video delivery requires no additional infrastructure and acts as a de facto mobile tv standard the industry lacks. However, it has a flaw: video hogs the precious cellular network capacity needed to deliver operators' premium paying services, such as voice and data. Operators are thus in a bind; they need to support mobile tv, yet baulk at the cost of rolling out a broadcast network. And while operators can deliver content to users via the 3G network, they know that if personalised video viewing takes off, network capacity will not meet demand (see box). This explains why chip vendors remain confident about broadcast mobile tv. "If consumers want tv, one way or another it will need to be broadcast to the handset," said Yannick Lévy, ceo of mobile tv chip firm DiBcom. ABI Research confirms its optimism, forecasting that cellular mobile tv subscribers will grow from 23.1million in 2008 to 216.2m in 2013. This growth, says ABI, will occur once mobile tv becomes an extension of broadcast tv services, rather than an add on to a long list of preferred cellular services. Serving tv on the go Delivering broadcast tv, like cellular, requires radio spectrum and sites for equipment and antennas. And, like cellular, hefty investment is needed for good signal coverage. "Cellular operators have had coverage problems for years and mobile tv will be no different," said Heath. Moreover, users tend to watch mobile tv indoors, where the signal strength is reduced, impacting viewing quality and further adding to the cost of achieving good coverage. "Outdoors coverage is not an issue," said Jashek, citing DVB-T coverage. "But indoors, depending on the country, it [signal coverage] is a challenge." Qualcomm's MediaFlo network provides broadcast tv to 84 US metropolitan areas and will top 100 by the end of 2009. Walker argues that operators can share broadcast networks just as they are starting to do with cellular. "A mobile operator can run a broadcast network or can share a network with others," said Walker. "There is no need if the content is the same, it is a terrible waste." Two operators in Italy already share a DVB-H network, he said. The chip vendors have long believed that multiple tv standards will coexist. "We realised the market would be fragmented from day one," said Jashek. Siano's latest ic, the SMS1230, supports DVB-T, T-DMB, and ISDB-T, as well as DAB/+ and FM radio. DibCom's DIB10098 supports all flavours of DVB, including satellite, T-DMB and DAB/+, while Qualcomm's silicon supports MediaFlo, DVB-H and ISDB-T. According to Walker, implementing multistandard silicon is not particularly taxing: all the standards use orthogonal frequency division multiplexing (OFDM) as the transmission signalling scheme. And the OFDM unit, which performs signal processing techniques such as the fast Fourier transform, comprises a large part of the silicon. OFDM encodes video data across a wide channel signal that is robust to frequency selective fading. A mobile tv receiver within a handset or netbook requires an rf front end and baseband ics. The baseband ic comprises two main functions – the OFDM unit and error correction. In addition, each company adds its specific distinguishing hardware to enhance the quality of the video bit stream. DiBcom, for example, compensates for Doppler shifts in the received signal if the handset is on the move – in a car or on a train, for example. "This results in a loss of orthogonality [between the OFDM tones]," said Lévy. DiBCom also supports reception from more than one source. The received broadcast can thus arrive via two antennas, each path experiencing its own channel fades. By combining the two received signals, reception is improved since different tones are likely to suffer fading in each of the signals. However, such an approach adds silicon complexity. Belgian microelectronics research institute IMEC is taking mobile tv hardware one step further by developing a software defined radio that implements mobile tv on a general programmable processor. IMEC views mobile tv as no different to any other wireless protocol that a handset processor will need to implement, such as Long Term Evolution (LTE) and Wi-Fi. "We see the mobile tv as part of the software defined radio," said André Bourdoux, principal scientist at IMEC's wireless research group (see NE, July 3, 2008). IMEC has developed an rf front end that captures signals from 88MHz (fm radio) to 5GHz, while its programmable baseband processor supports LTE, IEEE 802.11n, DVB-T and DVB-H. A multistandard solution requires 25% more silicon than a single standard ic, said Bourdoux, but it has a significant effect on overall space and system cost compared to a multiple ic design. Reasons to be cheerful The chip firms point to several factors why mobile tv will ultimately succeed. Japan is working on next generation networks and operators are moving to a paid for service, rather than free, said Lévy. Siano's Jashek highlights China as a key test case market as mobile tv will move from a free to a paid service. "But, unlike Europe, it will be reasonably priced," he said. Qualcomm's Walker points to events like the Olympics and Michael Jackson's death, instances where US 3G networks were unable to meet viewing demand. "There are circumstances where you need broadcast networks." But Heath is not so sure that broadcasting networks are the only solution. "The only viable approach to get to every device is 3G," argues Heath. "But the looming issue is that, if it takes off, the 3G network does not have the capacity." He believes mobile operators will use femtocell and Wi-Fi networks to deliver video, as well as 'sideloading', where video is downloaded to a pc hard disk and synchronised with the handset for later viewing. "Wireless LANs, femtocells and sideloading can substantially reduce the loading on 3G networks," said Heath. The reality is that a combination of broadcast, cellular and other wireless and wireline networks will be required for mobile tv. New consumer designs, such as mobile innternet devices and netbooks, will likely further grow the mobile tv market. "Mobile internet devices and netbooks have bigger screens and will have access to video – even high definition," said ABI's Orr. Such devices are appearing that require higher data rates, from 256kbit/s to 1Mbit/s, he said. At September's IBC show, 3d tv was the big theme. That will require two high definition video streams. "History has shown that processing power has always advanced faster than transmission bandwidth," said Lévy. "That has been true until now, but will it continue forever?" A history of mobile tv Companies have long believed that tv on the go can repeat the success of the transistor radio market, from one per home to one per user. Early portable designs had to deal with reducing the size of a tv's cathode ray tube. In 1970, National Panasonic launched the TR-001 mini tv that weighed about 1kg. Yet, despite its bulk, it only had a 1.5in screen. Sir Clive Sinclair launched his first design in 1977. The MTV1 looked like a portable oscilloscope and cost £200. He tried again in 1983 with the FTV1, which followed a year after Sony's first mass produced Watchman TV. The FTV1 was an £80 2in flat screen tv, involving a who's who of UK design and manufacturing firms. The tv's ic was codesigned and manufactured by Ferranti, Timex assembled the flat screen tube, while Thorn made the sets. Yet, despite Sir Clive's hopes, the device never took off; one reason being the tv required 6V lithium batteries that cost £10 a time. Sony's Watchman fared better and, in 1990, Sony launched the first colour tv that used an active matrix lcd. "It had a limited success and wasn't intended for the mass market," said Jeff Orr, senior analyst at ABI Research. "Its usage was mainly part time – for camping and travel – something you'd keep in the car." DiBcom started work on delivering tv to cars in 2000. In 2003, it developed a USB stick to deliver DVB-T to laptops. It was only in 2005 that interest in handsets for mobile tv took off, first in Japan and South Korea, and then Europe with the DVB-H standard. Why TV over 3G hogs capacity For chip companies like Siano and DiBcom, broadcast mobile tv has a minimum performance specification – a data rate of 384kbit/s and a display rate of 30frame/s. Yet, for 3G networks, the data rates are more modest: 128kbit/s and 15frame/s being common.