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Handset features still not a wrap

Posted: 16 May 2006 ?? ?Print Version ?Bookmark and Share

Keywords:Loring Wirbel? smart phone? PDA? mobile? video?

The product-definition uncertainty that roiled the smart phone and PDA communities a decade ago has returned with a vengeance, as advanced services like mobile broadcast video and HSDPA, HSUPA for 3G mobile apps" target=_blank>high-speed downlink packet access (HSDPA) leave handset developers pondering what to keep in and what to leave out of a slim-line design.

At the recent CTIA Wireless 2006 show, the smart phones, broadband PDAs and gaming platforms displayed were all over the lot. Even as companies such as Samsung and Kyocera unveiled their first slim-line handsets in the wake of the Motorola Razr, chipset makers and OS vendors spoke of additional networking and location-based capabilities that will force handset developers into critical choices.

"There are so many combinations of services possible, but only a subset reasonable for any given phone," said Scott Bloebaum, deputy CTO at Sony Ericsson Mobile Communications USA Inc. "It's a struggle to decide how many variations of a prototype to develop because neither the handset manufacturers nor the carriers want to miss out on something that might unexpectedly take off."

A single phone can sport combinations of Bluetooth, wireless USB/UWB, 2.4GHz and 5GHz WLANs, GPS location, VoIP, voice-over-WLAN, HSDPA, IP video stream processing and true mobile video broadcasting. But in the real world, users may balk at the complexity and cost of a phone with too many bells and whistles. And for designers, a handset is limited by the power dissipation problems of large displays and 3D graphics, the QoS processing of multiple low-latency services and the multitasking demanded of an embedded OS running several applications.

The latter factor can be solved by advanced real-time kernels, said David Wood, executive VP for research at Symbian Software Ltd, but handset developers demand cut-rate, high-volume unit pricing for an OS that must carry the multithreading features demanded by high-end PCs.

"We've had to move to advanced multitasking capabilities, including individually-preemptible threads, in release 9.0 of our software," Wood said. "Just because the hardware gets better, it doesn't mean the kernel can be less complex. Unless you are very careful in choosing algorithms, software keeps expanding to fill the available space."

In supporting real-time video broadcast, for example, Symbian can't assume that customers will be interested only in non-real-time IP "clipcast" streams. Early trials in Europe and the United States suggest that many consumers will want a mix of true mobile broadcast video and short video-on-demand IP clips, Wood said. The handset's OS must support both.

Handset developers also want to expand the capabilities of true 3D graphics, betting that some gaming communication platforms may end up resembling a horizontally-oriented, large-screen PSP game player rather than a traditional phone. At some unknown crossover point, such devices might require Wi-Fi or even WiMAX client capability, but may stop embedding circuit-switched telephony, said Bloebaum of Sony Ericsson. Indeed, he said, the potential for platform iterations is "mind-boggling."

Gateway capabilities
Chipset developers are responding with capabilities previously offered in residential gateways or home routers.

STMicroelectronics, for example, bypassed early 802.11n silicon in favor of a low-power, dual-band media access controller that supports 5GHz and 2.4GHz services. Dual-band 802.11a/g support is a no-brainer at a time when 2.4GHz networks in the home are becoming interference minefields. More surprising is that ST is targeting a 5GHz chip for a cellphone, not a residential gateway.

"With packet voice and high-speed data both becoming drivers for a portable device, we see the phone and the multifunction platform as the primary market for 5GHz Wi-Fi," said John Prince, product marketing manager for WLANs at ST.

Bloebaum of Sony Ericsson sees 5GHz handset markets as a niche for the time being, and believes even 2.4GHz phones that hand off between cellular and WLAN services will be a challenge because of the high power dissipation of in-building packet voice. The popularity of VoIP will make the IP phone a popular item in a handset developer's portfolio, Bloebaum said, though a carrier may never be able to eliminate legacy connectivity to circuit-switched networks.

Freescale Semiconductor Inc.'s iMX 21 applications processor and LP1020 WLAN baseband have been recast with a new moniker, V2IP, under the assumption that handset developers will want video-over-IP as well as VoIP support, said Jim Berg, director of marketing for the cellular platform division at Freescale's wireless and mobile systems group.

Using a common ARM core for both baseband and applications processors, and implementing modems directly in DSP blocks allows Freescale to vary the supported applications in iMX and MXC implementations, Berg said. The flexibility of the architecture has also gained Freescale design wins in gaming-centric platforms like the Toshiba Personal Media Player.

The biggest surprise when carriers implement high-speed data is that operators do not necessarily demand the highest downlink rate possible, Berg said. At CTIA, Broadcom Corp. introduced an ARM11-based processor capable of meeting 7.2Mbps data rates, but Berg said Freescale is shunning 7.2Mbps for now in favor of supporting multiple circuit-switched calls alongside 3.6Mbit speeds. In fact, Berg said, carriers are asking chip vendors to support high-speed uplink packet access more aggressively than they are demanding downlink speeds greater than 5Mbps.

Video demands
On the video front, Texas Instruments Inc. demonstrated the viability of DVB-H video by installing its Hollywood processor in the Modeo network shown at CTIA. While Freescale's applications processor can support packet video streams, the company still is unsure what mix of on-demand packet video clips will be required. Freescale is investing in the DVB-H standard for broadcast, Berg said, but "the whole issue of dedicated video networks is still a great big TBD [to be determined]. Is the consumer going to accept a great outdoor service and a so-so indoor service on the same mobile platform?"

For the past several years, teenagers have replaced high-end business customers as the end users with greatest demand for bandwidth, graphics performance and multitasked apps. This year, China-based handset OEMs including ZTE Corp., Huawei Ltd and UTStarcomm Personal Communications are coming to North America after offering sophisticated phones to discriminating Asian teens. Often, they are brandishing midrange handsets to appeal to carriers here that are less aggressive at pushing advanced services than their Asian counterparts, said Sanjeet Pandit, senior director of global business development at ZTE USA Inc.

In addition to a San Diego-based research organization that works with its close partner Qualcomm Inc., ZTE this year established a large sales and marketing organization in the Dallas region to challenge the current mix of South Korean, American, Finnish and Japanese powerhouses among the handset OEMs. While ZTE already offers a range of GSM/UMTS phones in some regions, it will enter the U.S. market with a sole focus on CDMA.

"We find that we have to customize the applications not only to the countries and regions, but to the operators and their vertical markets," said Pandit. "Today the notion of video on the handset means video-on-demand from a centralized server. In the future, that may mean real-time broadcast or IP multicast, but the handsets must be ready for the time that becomes a reality."

Similarly, ZTE is developing high-speed graphics options for game-centric phones, but "we can't lose sight of the fact that these will be phones first," Pandit said. "Graphics performance cannot interfere with the basic ability" to take and make calls.

ZTE is backing up its IP-centric handset approach with infrastructure equipment that uses TCP/IP protocol stacks from cell tower to network switch, based on ver 5 of the Internetwork Operating System.

Just as Wi-Fi for the handset is finding a willing design base, assumptions for WiMAX are changing daily. Intel Corp.'s original push for 802.16e was to provide pseudo-mobility for the original 802.16d standard, delivering at least some of the nomadic features promised by the original proposal for mobile broadband, 802.20. Now, WiMAX Forum members assume the real drive for 802.16e is to lower the cost of customer premises equipment (CPE) client platforms. But whether that means residential gateways, laptops or even WiMAX-enabled handsets and PDAs depends on the design assumptions and the time lines envisioned.

Carlton O'Neal, VP of marketing at Alvarion Inc., said the heavy interest from municipal governments in 802.16 suggests that fixed broadband as a public infrastructure will keep a near-term focus on home-based clients operating in city environments. Alvarion thus has development efforts in 802.16d/e.

Michelle Pampin, global strategic planning director at Harris Corp.'s microwave communications division, said that the company gave up on multipoint radio in favor of point-to-point backhaul when Harris saw Intel pushing 802.16e as the only path to bring wireless broadband to mobile clients. "This could mean that 802.16d becomes a niche business," Pampin said. "The 'e' version is driven as the only viable WiMAX in the name of reduced CPE costs, and that could drive it into handsets quicker."

Motorola Inc. is offering a tiered range of services in metro markets, combining Canopy unlicensed products, MotoMesh Wi-Fi mesh networks and its first 802.16e products, using subscriber-terminal design techniques borrowed from Canopy. As Motorola moves its WiMAX networks into production, it will develop tiered bundles for cities that integrate both 802.11 meshes and 802.16e backbones.

- Loring Wirbel
EE Times

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