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Getting the picture on mobile TV

WE WILL, IF THE PRODUCT-MARKETING PEOPLE SEE THE FUTURE CORRECTLY, VERY SOON ALL BE WATCHING TELEVISION ON OUR MOBILE HANDSETS. WE WON'T—AS AT ONE TIME THE INDUSTRY'S VISIONARIES WOULD HAVE HAD US BELIEVE—BE DOWNLOADING THAT CONTENT OVER 3G NETWORKS. INSTEAD, A NEW GENERATION OF HAND-HELD DEVICES IS IN DESIGN, INDEED IS ALREADY COMING INTO SERVICE, WITH YET ANOTHER OPERATIONAL MODE. WE DON'T KNOW EXACTLY WHAT THE CONTENT WILL BE, NOR WHO WE WILL BUY IT FROM—BUT THE SILICON IS HERE, THE TRIALS ARE DONE, AND IT'S FULL STEAM AHEAD WITH PRODUCT DESIGN.

The mobile services market is no place for the timid. Operators across Europe are engaged in a grim search for some service—any service, you might say—that they can persuade subscribers to pay for, other than voice and text messaging. Any prospect of recovering the huge sums paid, several years ago now, for 3G licences is still a distant hope, if not abandoned altogether. Meanwhile, the revenue stream from those voice calls is far from safe—European regulators have their sights fixed on lucrative international roaming charges, while competitive pressures in the various domestic voice-call markets continue unabated. Meanwhile, Wi-Fi hotspots proliferate and the first WiFi/cellular handsets capable of VoIP (voice-over-internet-protocol) are entering the market, further threatening the only secure revenue base that the operators have. Service providers must look with envy at their counterparts in territories such as Japan and Korea, with their long-distance-commuting populations ready and willing to part with their money for extended mobile services. But, as the operators have learned to their cost, extrapolating from the reactions of Pacific-rim consumers to infer customer behaviour in the West is a risky business.

As if to make things worse, the next attempt to part mobile consumers from their money may not even send much— if any—revenue the way of the cellular operators. The aspect of provision of mobile TV that is least clear is who will pay for it, how it will generate a revenue stream and how, and how much, the consumer will pay—if anything at all. TV that users watch on a cellular handset has become the most common expectation for the mobile terminal, but the growth in alternative hand-held platforms is departing from that model—manufacturers are considering adding the reception capability to products such as portable media players and gaming platforms. Nevertheless, operators appear to be joining the two statements, “some mobile services make money,” and “television is a saleable commodity”— underpinned as much by hope as anything else—into a solid equation from which the product is revenue.

If commercial viability is uncertain, it is not slowing the pace of product development at all. In recent weeks and months, semiconductor companies have announced a large number of chip and chipset products to support the development of terminal products. The choice of standards that was such a big issue in the initial phase of planning services and launching trials is already almost irrelevant in the design of mobile terminals, as silicon vendors are announcing multistandard chipsets. It would be convenient for product planning if—given that different standards exist—each geographical region had opted for a single type of service. As ever with standards issues, the reality is not so simple.

Several trials and initial service around Europe, and in the USA, employ the DVB-H (digital video broadcasting to handsets) standard, which ETSI codifies. In Beijing, operators are commencing services now, with the objective of having the system in widespread use for the 2008 Olympics, using DMB (digital-multimedia broadcasting) in its T-DMB (terrestrial- DMB) variant. Korean operators already have the same standard iin service. DVBH is a derivative of the DVB-T digitaltelevision standard that is already in place in many countries. The DVB-H standard allows transmission either embedded within a DVB-T service, using the same transmitters, or alongside DVB-T, broadcast from an independent transmitter network. In the channel space that one full-rate DVB-T signal would normally occupy, the DVB-H format transmits several television channels at a lower data rate. To the DVB-T standard, it adds features such as time-slicing and forward-error-correction. Time-slicing packages multiple data streams (TV signals) as time-multiplexed bursts that—obviously—allow for multiple channels: but the multiplexing serves a further major purpose for the mobile terminal. With prior knowledge of when to expect the next burst of data for the channel it is receiving, the terminal can operate its receiver on a low duty cycle, only powering up when it “knows” a burst is due. This drastically reduces the power needed, and is key to making a batterypowered terminal viable. Extensive FEC techniques, together with the well-known resistance of OFDM (orthogonal frequency- division multiplex) modulation provide sufficient resistance to fading and multipath effects to ensure reception in moving trains and vehicles.

DMB, conversely, also an ETSI standard, is a variant of the Eureka 147 DAB (digital audio broadcasting) standard. Just as with the DVB case, the detail of the signal construction and coding of the TV data stream is extremely complex, but essentially, the space that several audio (radio) channels would occupy in the DAB multiplex is concatenated to carry a TV signal. The originators of DAB created it for mobile reception, so it already has coding schemes that cater for multipath and fading effects. The USA has gone its own way in digital radio, so the spectrum allocation to carry out DAB-based trials and initial service provision is not available there. Other variants exist, notably in Japan, which has a separate system for mobile TV, known as ISDB-T.

The mobile-reception task is challenging, not least in the perennial conflict between providing sufficient receiver sensitivity while holding power to a level that will ensure battery life that is acceptable to consumers. A recent paper from Microtune neatly summarises some of the special challenges: “DVB-H tuners will need to tune across the UHF band IV-V frequency range (470 to 860 MHz) with 6-, 7- or 8-MHz channel bandwidths in Europe and the L-band 5-MHz channel at 1670 MHz to 1675 MHz in North America. The situation is particularly challenging in Europe, where the spectrum is fragmented by country, and cellular transmitters are often spread into the same bands as mobile TV.” Where the mobile platform is a GSM phone, the co-located GSM transmitter in the handset exacerbates the problem. The cellular terminal is in contact with the base station irrespective of whether or not a call is in progress: if the user is watching TV, reception must continue uninterrupted while the cell phone transmits—Microtune estimates that you need a 20-dB margin of out-of-band rejection to cope with that factor alone. Microtune, based near Dallas, Texas, designs and manufactures a range of RF products for entertainment and communications functions, one of its most recent introductions being the MT2060/ 2066 tuner chip for DVB-H hand-helds.

As is frequently the case with digital radio signals of almost any type, the design process involves a partitioning decision. Some chips on the market—the Microtune approach being an example—favour a complete tuner function, which the company builds in an RF semiconductor process and that feeds a separate, CMOS, baseband chip. Alternatively the singlechip approach integrates tuner and baseband processing functions, although you may still need some external RF filtering and, perhaps, a low-noise amplifier for a complete solution.

Last month we reported in EDN Europe on the tuner chip that start-up Mirics offers. From antenna switching through to I/Q output, the company’s MS1001 exemplifies the dedicated-tuner approach— Mirics says it can receive any known format of mobile TV broadcast that broadcasters use anywhere in the world, including DVB-H, T-DMB, ISDB-T, DAB-IP, and MediaFlo, as well as DAB, DRM and AM/FM radio, and that spans all bands from 100 kHz to 1.9 GHz.

SiGe, the chip vendor specialising in silicon-germanium devices—perhaps unsurprisingly— endorses this approach. The company does not have a mobile-TV product but hints that it may enter the market: on the occasion of the introduction of its latest GPS receiver IC (see “Softwareradio navigation receiver awaits Galileo” on pg 22 of this issue), the company indicated that it believes that the principle of building critical RF functions in a suitable technology, on a separate chip, holds good for hand-held TV applications.

Likewise, Integrant Technologies, the Korean vendor that Analog Devices recently purchased, offers low-power radio tuners for digital TV and digital radio broadcasts, especially the DMB tuners it provides to Korean cellular handset builders. Integrant also delivers tuners from the same product family to support the new ISDB-T mobile TV standard in Japan. The product line-up includes the MTV102 DVB-H RF tuner IC as well as the IDT3010 T-DMB receiver.

This year’s IBC congress, which took place in September, prompted a flurry of announcements: for example, Frontier Silicon announced its Paradiso FS1030 multi-standard digital-TV-baseband IC (Figure 1), which supports DVB-H, DVB-T, T-DMB, DAB-IP and enhanced-Paradiso to address the myriad of mobile- TV handset-receiver standards resulting from differing regional-deployment and spectrum-regulation plans. Frontier is working with a number of protocol-stack developers to optimise Paradiso operation for specific standards. Features inlcude integrated 2-Mbit MPE-FEC memory and Reed Solomon decoding for advanced Doppler and multi-path channel algorithms; enhanced-packet and data-group modes for T-DMB/DAB-IP; multiple PID, section and IP stream filters; and an extensive set of peripherals including SPI, SDIO and USB interfaces. The interface to the host-application processor offers IP datagram, MPEG-2 Transport System (TS), Fast Information Channel (FIC) or Main Service Channel (MSC) output streams with control and boot mechanisms. Frontier built the chip using the Meta multi-threaded processor and UCC (universal communications core) IP cores from Imagination Technologies.

Multi-standard is a significant theme that extends through to the software players that run on the mobile devices— whatever platform that turns out to be. At IBC 2006, software company Inter- Video teamed with silicon vendor Siano Mobile Silicon to show its iMobi DTV player with Siano's SMS1000 on handheld devices. iMobi is a universal DTV [software] player that supports DVB-H and T-DMB on both hand-held devices and laptops: the SMS1000 is a quad-band, multi-standard mobile-DTV receiver. The chip supports DVB-H, DVB-T, DAB, enhanced-packet-mode DAB (IP-DAB) and T-DMB mobile digital standards.

Likewise, Frontier is partnering with and Silicon and Software Systems (abbreviated to S3), a provider of mobile-DTV client software, to develop a reference turnkey solution for multi-standard mobile DTV, enabling handset manufacturers to deploy “world-ready” mobile devices based on DVB-H and T-DMB standards. S3 named its mobile-TV client software onHandTV.

Time-to-market pressures to get mobile TV into consumers’ hands will prompt many more such alliances that will spawn complete RF-to-software reference designs. S3 is also involved with Texas Instruments and PacketVideo in a demonstration of PVR (personal-video-recorder) and PIP (picture-in-picture) functions within a mobile-TV environment. TI is an exponent of the single-chip approach to mobile TV, with its Hollywood highlyintegrated offering.

With the Hollywood chip (DTV1000) and TI’s OMAP mobile-phone processorbased product, consumers can watch live TV and store broadcast content on their mobile devices. The PVR and PIP demonstration uses PacketVideo's pvTV client solution for DVB-H, which combines the pvTV client software and the pvTV reference hardware platform. TI builds its single-chip DVB-H solution, DTV1000, in 90-nm RF CMOS, positions it as a solution for mobile DTV-enabled personal media players, and provides an integrated tuner, demodulator, decoder and memory on one piece of silicon. To enable functions such as the PVR and PIP applications, the DVB-H receiver must be able to process multiple services, such as two TV channels simultaneously (concurrently or back-to-back) without increasing system-memory cost and footprint—a capability TI says it has achieved in the Hollywood device.

On the infrastructure side of the mobile- TV equation, UK-based RadioScape— long a pioneer in the development and deployment of DAB—has announced that the digital multi-media broadcasting service that Beijing Radio Stations and its affiliated company, Beijing Jolon Media, introduced in September 2006 is employing its Professional Broadcast System. This service provides digital audio and video programs for mobile devices such as cellular phones, PDAs, and MP4s (advanced video players). Features of the system include enhanced-packet-mode data that delivers DAB-IP services, the enabling of integration of third-party conditional-access systems, advanced electronic-programmeguide (EPG) features and the ability to support Asian language labels, DLS and data carousels. RadioScape has also worked with BT in the UK on the inception of the BTMovio service, which embodies the revised EN 300 401 specification. In that specification ETSI included a facility to mix audio, video and data on a DAB network using IP (internet protocol).

In this view, delivery of service such as mobile TV is not defined by the particular standard used in the transmission, but becomes IP-centric, allowing 3G, WLA, DAB and DVB-H—and possibly others— to play a part in delivering content of all forms. BT Movio has launched with DABIP in the UK, giving access to several TV channels as well as existing DAB content, but does not rule out incorporating other IP-capable broadcast standards when and if they become available.

The mobile-TV sector continues to generate (component) announcements at a fast rate; for example from Dibcom, with its DIB7070-H, DIB7070-P and DIB7070-M single-chip (RF and baseband) parts for DVB-T and -H. Newport Media (www.newportmediainc.com) is sampling its Sundance H hardware/software solution that it based on a CMOS, quad-band direct-conversion radio tuner plus DVB-H demodulator; Samsung, as well as being a builder of handsets, also has a semiconductor-level product in the market—and the list goes on. As the membership list of the DVB-H organisation (www.dvb-h.org) reveals, there are few major semiconductor vendors that do not either have a product in this space, or look set to introduce one.

MOBILE VIDEO ARCHITECTURE CHOICES Once you have received and decoded the mobile television signal—whatever format it arrives in off-air—you will need to display it. Ron Wilson, Executive Editor of EDN in North America, writes: "Consumer-electronics manufacturers are rushing past handheld DVD players to compete against the Video iPod. Handheld receivers for the emerging DVB (digital- video-broadcast) standards are on everyone’s drawing boards. Video approaching VGA (videographics- array) resolution is flickering to life in cell-phone handsets. And in each one of these markets, the most forwardlooking pundits are predicting the arrival of highdefinition handheld devices. All of this could be an obvious benefit to consumer- electronics and handset manufacturers, persuading consumers to rush out and buy another multihundred-dollar toy and again replace their cell phone while they are at it. But the growing demand for decent video on handheld devices is posing a serious challenge to system designers, and it is confronting system architects with a too-large menu of hard choices." Read Ron’s complete article, which explores the architectural choices that lie ahead when specifying mobile video systems, at www.edn.com/article/ CA6363902.