e2001 Your Digital Future - Bangkok Post Special Supplement

CELLPHONES

Making sense of mobiles

New technology, old hassles

Tony Waltham

The local cellular phone marketplace seems to be more like a test-bed of all the different technologies available, most of which are incompatible with each other _ or a marketplace that cannot decide which technology to adopt. We still have the early analog AMPS system and even an ancient Nordic Mobile Telephone system that chugs along, while since then every flavour of digital wireless telephony has been introduced.

All of this makes for a fragmented marketplace when it comes to both handsets and services, with a lot of expensive redundancy in equipment that has to be installed separately for each network. There have been some opening shots from operators here offering data services, although the lack of a dominant mobile phone standard here undoubtedly holds things back.

Will the promise of 3G (third generation) mobile services that the International Telecommunications Union (ITU) agreed upon last year help to resolve this problem? This agreement was known formally as the International Mobile Telecommunications for 2000 MHz or IMT-2000.

How and when will we get the promised 2 Mbps wireless data rates for indoor fixed terminals, 384 Kbps for outdoor terminals at walking speed and 144 Kbps at driving speeds?

It is very likely that we will again be facing more incompatible standards and systems that will ensure a repeat of higher costs and poorer coverage that we might have been getting were we to have a single dominant system.

Despite the fact that the ITU managed to get all major operators and equipment suppliers to sign an agreement on harmonisation for a 3G mobile system, this was not the same as a single standard.

So the world is now ready to move forward with three camps embracing mostly incompatible systems. One group is led by CDMA pioneer Qualcomm, with its cdma2000, another (of the GSM operators) is spearheaded by Ericsson, who will go for wideband CDMA, while a third offering from another group in the US is following an AT&T technology called EDGE, which extends the speed of TDMA (for definitions, see below).

Each system provider has invested billions of dollars in equipment and aggressively defends and promotes its technology, and consequently, the mobile phone subscribers of this world will be restricted in their ability to roam _ although the ability to provide dual-mode or multi-mode handsets may help overcome this.

The first broadband or 3G wireless networks are now poised to be rolled out in Japan next May by NTT DoCoMo, and the system there will offer 386 Kbps mobile links and 2 Mbps fixed links.

It will have to be seen what the schedule will be here.

CDMA: Code division multiple access: Multiple signals, each with a unique code, are sent across the same 1.25 Mhz frequency spectrum. Receivers only decode the message with their code. Used in the US (by Sprint, Verizon) and in Asia. It arrived a bit late on the scene, after GSM was established.

TDMA: Time division multiple access: Spectrum is divided into narrow channels, and sliced by time. Used in the US by AT&T, Bellsouth.

GSM: Global system for mobile communications: Established by a European-wide agreement among manufacturers, operators and governments and made popular by roaming and economies of scale. Based on TDMA. Also found in Asia and in parts of the US.

GPRS: General Packet Radio Service: Higher-speed data transmission for GSM networks with commercial operations to begin early next year.

EDGE: Enhanced data rate for global (or GSM) evolution: Will use enhanced TDMA technology for 3G data speeds and will be compatible with both GSM and US TDMA networks.

W-CDMA: Wideband CDMA. This high-speed CDMA is based on Qualcomm technology but has been significantly modified by Japanese and European manufacturers and is the GSM operators chosen 3G technology. It is expected to dominate the world outside the US.

cdma2000: Name for a high-speed version of CDMA that is compatible with existing CDMA networks and to pioneer later this year in Korea. Will be the 3G technology for existing CDMA operators in the US and Asia. Said to be more efficient and better quality.