Cell-phone handsets may soon double as video screens or home-appliance controllers thanks to third-generation wireless technology.
Edited by Leland E. Teschler
Will you be watching Phantom Menace on your next cell phone? Or perhaps using it to blast your way out of a skirmish in an online game of Quake? These are possibilities if wireless phones become platforms for games, streaming media, and other PC-style applications.
It's not clear that there will ever be much of a demand for cell phones able to handle such seem-ingly exotic uses. Nevertheless, that hasn't stopped telecom sup-pliers from doing the groundwork necessary to make such developments possible.
Planning is well underway for what are called third-generation (3G for short) cell phones. The 3G phones are envisioned as part phone, part PDA (personal digital assistant), and part video-player on demand.
A hint of these capabilities is due to soon arrive in the form of Samsung's MPEG-4 Video Phone and Nokia's 9210 Color Communicator, both powered by a special chip from Emblaze Systems Ltd. in Israel. The screen on the Samsung device is said to have 16 million-color display capability and 1 million-pixel resolution, and will allow viewing video at 15 frames/sec. It is currently operational in Korea over a 3G wireless network and is slated for U.S. debut later this year. The Nokia device is expected to become available this year as well.
Handsets able to provide such features obviously pack a lot of electronics into a small package. Therein lies a challenge for designers.
"Designing user interfaces that keep controls and displays large enough to be user friendly on increasingly smaller devices becomes extremely important," says Randy Roberts, manager, Digital Convergence for Nokia. "Additionally, people now see mobile phones as fashion accessories, rather than just communication tools. There is the challenge of making sure that phone designs are also in step with the current fashion trends."
Tony Indindoli, general manager of Innodesign agrees. "Cell-phone design used to be all about reducing size and weight, and while those are still important criteria, more and more the challenge is to differentiate your phone in the marketplace. Style and finish become important as people begin to view phones as not just a device, but as an expression of their individual identity."
Based in Palo Alto, Calif., Innodesign recently used Unigraphics CAD/CAM software to design the TouchPoint 3000, a handset manufactured by LG Electronics in Korea and marketed by Sprint. The design conceals a proprietary PDA user interface (not based on either the Palm or Windows CE platforms) beneath the keypad and LCD.
Thermal management is also becoming an increasing concern, as cell phones get smaller and more powerful. "Especially in a hot climate," says Mark Hodes, a researcher at Lucent Technologies' Bell Labs. "A cell phone can quickly become uncomfortable after prolonged use and the reliability of the electronics is very dependent on temperature."
The electronics inside most cell phones is designed to operate at temperatures up to 100°C. "But you don't want to be operating a phone near that maximum temperature," Hodes cautions.
In one effort to address this problem, Hodes and colleagues at Bell Labs and Villanova University experimented with Phase Change Material (PCM), a waxlike organic substance, lining the cell-phone handset itself. The experiments did not result in a material incorporated in an end product. Nevertheless, they illustrate the direction of current thermal-research on portable electronics.
The materials tested were alkane tricosane and Thermosorb-122, a microencapsulated PCM manufactured by Frisby Technologies, Winston-Salem, N.C. The Thermo-sorb-122 is in the form of a powder consisting of capsules of one to several hundred microns in diameter which are 80 to 85% organic PCM by weight.
As the temperature increases, the wax melts and absorbs heat. This boosts handset reliability and the time a user can comfortably hold it. The Bell Labs experiment borrowed on earlier uses of PCM in such equipment as infrared cameras used by firefighters, wearable computers, and even thermal packs which can be heated or frozen.
And then there's 3G
One reason for the excitement about 3G phones is that they will bring users an "always on" Internet connection at up to a 2 Mbits/sec rate. You're 3G phone will instantly notify you of incoming e-mail, for example, and the Internet will be available without the need to log in. (To make a call, of course, you'll still have to punch in a number or at least say it out loud). These smart phones are likely to usher in services like buying tickets over the wireless Web, or even charging vending machine purchases on your credit card.
Depending on the expert quoted, it might take as many as three years for 3G to come into full bloom. Services such as movies or news headlines beamed to handheld devices will come only when service providers make them available. For a glimpse at how such services would come about, it is interesting to see how phones equipped with the Emblaze chip will get multi-media content.
The Emblaze video decoder in the handset works in conjunction with a server maintained by Emblaze Systems Ltd. This server encodes video content in the MPEG-4 format for transmission to the handset. OEMs have to sign up with Emblaze to integrate its streaming video content. For example, Ericsson is deploying the service over the GPRS (General Packet Radio Services) it provides. Ericsson is said to have pilot programs in place with about 25 cellular carriers to deliver news content.
Estimates are that there will be 1.2 billion cell phones in use by 2005, and that perhaps 40% of those will be enabled for streaming media.
European cell-phone users will likely be the first to see futuristic programming simply because Europe has one standard for transmission and information encoding: GSM, for Global System for Mobile Communications. GSM was developed in the early 1980s to permit roaming throughout Europe. In contrast, the U.S. wireless industry employs multiple standards. It's unlikely they'll evolve into a single standard soon. That means vendors fielding wireless networks each have to make their own arrangements for providing entertainment and video.
In Japan, NTT DoCoMo expects next month to begin broadband mobile phone services capable of delivering video, CD-quality sound, and fast Net access. The mobile Inter-net access provider will use a transmission standard called W-CDMA. There are European mobile phone operators currently working with W-CDMA as well.
But San Diego-based Qualcomm Corp. is instead promoting cdma2000, a competing standard which will appear in Korea and Japan as well as the U.S. later this year. Both W-CDMA and cdma2000 are based on code division multiple access (CDMA). Carriers currently using CDMA technology are expected to migrate to cdma2000 for 3G phones.
CDMA uses digital-encoding spread-spectrum radio techniques. It breaks up speech into small, digitized segments and encodes them to identify each call. It lets a large number of users share the same band of spectrum. This has the benefit of greatly increasing system capacity. CDMA offers more than 10 times the capacity of existing analog (AMPS) systems and three times the capacity of TDMA (Time Division Multiple Access). TDMA is a digital wireless technology that divides a narrow radio channel into framed time slots (typically three or eight) and allocates a slot to each user.
Qualcomm has also devised a software platform for developing applications on its CDMA-based wireless devices. Called Brew, for Binary Runtime Environment for Wireless, it uses features in Qualcomm CDMA Technologies' (QCT) integrated circuits.
"Brewable" phones may be out near the end of the year. They will let users download applications over the air through the carrier network, then configure the phone to use the software based on the phone's own capabilities. Qualcomm has signed up carriers and developers like Verizon, Sam-sung, and Kyocera to use Brew.
Brew might show up on wireless devices besides those using the CDMA format. Qualcomm says it will Brew-enable chips from other wireless chipmakers.
Finally, there is also a standard designed to extend GSM networks as are operating in Europe to 3G. GPRS, general packet radio service, provides wireless packet data access to mobile GSM users. The main feature of GPRS is that it reserves radio resources only when needed and these radio resources are shared by all mobile stations in a cell. This helps use network resources effectively for bursty data applications as in telemetry, interactive data access, and Internet browsing. Data rates of up to 115 kb/sec are supported.
The GPRS is designed to be embedded in the conventional GSM network architecture.
CDMA: Roots in radar
Ideas originally developed as a countermeasure for radio and radar jamming have proven to be useful for cellular-phone systems. A time-hopping spread-spectrum multiple-access system first described in 1949 was what later gave rise to CDMA (carrier-detection multiple access) technology. In a nutshell, the technique multiplexes coded signals onto a carrier in such a way as to create a signal having a fairly wide bandwidth. The beauty of the idea is that the information content of the signal is spread out over a large band of frequencies. Interfering signals, which typically have a relatively narrow frequency bandwidth, will be able to block only a small portion of the original signal. This means narrow-band noise or interference won't prevent receivers from being able to extract enough information to recreate the original information content. (Time hopping, not used in CDMA, refers to transmitting the information-bearing signal in short bursts where the times of the bursts are decided by a code signal.)
Qualcomm Corp. studied CDMA techniques in the 1980s and commercialized a narrowband form of it in 1993. Wideband CDMA techniques (bandwidths of 5 MHz or more) have been studied worldwide for use in 3G cellular systems.
In CDMA each user gets a special code sequence used to encode the information-bearing signal. The receiver knows the code sequences and uses them to decode a received signal and recover the data. The bandwidth of the code signal is much larger than the bandwidth of the information-bearing signal. This means the encoding process enlarges or spreads the spectrum of the information bearing signal, hence the name.
If multiple users transmit a spread-spectrum signal simultaneously, the receiver will still be able to distinguish between users, because of their unique codes. Correlating a received signal with a code signal from a certain user despreads only the signal from that particular user. Other spread spectrum signals remain spread over a large bandwidth. Put another way, the power of the desired user will be larger than the interfering power provided there aren't too many interferers.
OLEDs Sine qua non for 3G?
Many portable Internet applications now on the drawing boards will be practical only if there are economical, color video screens to display them. Enter Motorola's Timeport P8767. It is a hot-selling cellular handset that sports what is considered to be the most colorful and easy-to-read screen yet found on a wireless device. The reason: a new display technology called organic electroluminescence. Indications are that future versions of such displays could play an important role in emerging 3G wireless appliances.
The basic patents for these displays came out of Eastman Kodak in the 1980s, though organic electroluminescence was first observed in the 1960s. The display in the Motorola phone is from Pioneer in Tokyo, based on Kodak's patents. Other vendors have similar displays in the works. Industry observers think these devices could eventually edge out LCDs for small-screen displays, thanks to advances such as full-color capability and the potential for fabricating the displays on paper-thin plastic substrates. (Production devices today are on glass.)
Organic electroluminescent light-emitting diodes (OLEDs) sandwich special organic material between two electrodes, one of which is transparent. Electric current passing between the two electrodes stimulates the organic material to emit light. The color of this light depends on the particular material used. management
Compared to a pixel on an LCD, an OLED pixel has a greater viewing angle and responds more quickly. An OLED display consumes less power than an equivalent LCD because only the portions of the display actually lit up draw current.
An OLED is constructed on a glass substrate by first depositing an indium-tin-oxide electrode. On top of this transparent material goes either organic dye layers applied by thermal evaporation or polymers via spin coating. There may be additional organics layered on to enhance the injection or transport of electrons or electron holes. Total thickness of the organic layers is about 100 nm. A metal cathode made from materials such as magnesium-silver or aluminum alloy gets evaporated on top. The cathode metal is specially chosen to have a low work function for efficient injection of current carriers through the display element.
Cell-phone technology for dummies
Cellular phones are named for the system of dividing a geographic area such as a city into a number of small cells, each typically 10 square miles.
In a typical analog phone system, a carrier has approximately 800 frequencies to use throughout a municipal area, and because each cell base station uses low-power, the same frequencies can be reused, as long as they are in nonadjacent cells. The frequency range of the cellular band is 824.01 to 893.97 MHz.
Digital phones use digital transmission methodology, which effectively triples the number of available channels.
PCS (personal communications services) is essentially a digital cellular-phone network, using smaller cells, but requiring a larger number of antennas to serve a given area. It uses a different radio frequency than the current cellular system, 1850 to 1990 MHz. The FCC auctioned off the PCS frequency band to address capacity issues with cellular networks that would not allow for future growth.
There are a number of standards bodies now involved in developing mobile communications. Among the most well known is the International Telecommunications Union (ITU), an agency of the United Nations which is trying to establish standardized communications practices. IMT-2000 is the formal name for the process undertaken by the ITU to coordinate global third-generation wireless standards.
There are several modes of operation defined under IMT-2000. Among them is cdma2000 1x Multi-Carrier (1xMC), a CDMA mode which offers 3G capabilities within a standard 1.25-MHz channel. It doubles the voice capacity of existing CDMA systems and offers data speeds to 307 kbits/sec. Another is cdma2000 3x Multi-Carrier (3xMC), which uses three standard 1.25 MHz channels within a 5-MHz band and offers data speeds to 2 Mbits/sec. WCDMA/UMTS/Direct Spread uses one 5-MHz channel offering data speeds to 2 Mbits/sec. And Time Division Duplex (TDD) is a CDMA mode which allows transmission and reception of signals using the same RF band, by alternating transmission periods with reception periods.
Also active is the Operators Harmonization Group (OHG), industry operators that meet on harmonization issues. The OHG has agreed on a standard for 3G CDMA-format transmissions with three modes: Multi-Carrier (MC), Direct Spread (DS), and a Time Division Duplex (TDD).
A hint of things to come
Two new products that may be harbingers of future developments in wireless technology both garnered Best of Show distinctions at the recent Internet World Wireless Show 2001. The Digital Angel Corp. got the nod for its Digital Angel delivery system, which includes a wristwatch-sized miniature digital transceiver (bottom) that beams vital signs via wireless GPS system to a 24/7 physician-staffed call-center. Potential applications include: medical and location monitoring for at-risk patients; emergency location of lost or missing children; finding lost or missing household pets; managing livestock and other farm-related animals; pinpointing the location of valuable stolen property; and managing the commodity supply chain. Digital Angel data is transmitted wirelessly, on a real time basis, to an Internet-integrated ground station and made available on a Web-enabled desktop, laptop, or wireless device.
NeoMedia Technologies Inc. was also recognized for its PaperClick system which lets Web-enabled cell-phone users view specific pages on the Internet. A wireless bar-code scanner called the Quoder (top right) can be used to record bar codes to bring up pages later, if desired.