Siemens promo blurb on TD-SCDMA
JOhnG
globalsources.com
Expert Talk: Florian Kreutz, Siemens ICM
Posted: July 25,
2000
TD-SCDMA can
re-use major part of
existing GSM
networks
Since 1998, the China Academy of
Telecommunications Technology
(CATT) and Siemens have been
jointly developing a new standard
for 3G mobile networks, the time
division-synchronous
code-division multiple access
(TD-SCDMA) technology.
In an exclusive interview with
Global Sources Telecom
Products, Florian Kreutz, senior
press officer at Siemens ICM,
outlines why TD-SCDMA is
efficient in terms of radio
spectrum and the implementation cost is much lower than
that for any other 3G system. Excerpts:
Q: What exactly is the TD-SCDMA standard and what
can it do?
A : TD-SCDMA is a "real" 3G standard. It has been
accepted by the ITU as a 3G standard and is part of the
IMT-2000 radio standard specification, carrying, together
with TDD-UTRA, the official name IMT-TC (time code).
As far as the specifications are concerned, it satisfies 3G
requirements for a radio interface, supporting transmission
speeds from 384Kbps up to 2Mbps. It is also designed to
be compatible to UTRA (UMTS) networks. Work toward
integrating TD-SCDMA with UTRA (the UMTS network)
is undergoing in 3GPP. It is expected that TD-SCDMA
will, in fact, be included in release 2000 of 3GPP.
Among the main features of TD-SCDMA, it is important to
point out that it can support both symmetric and asymmetric
traffic. Whereas, symmetric traffic is generated by voice
and video, data transmissions (such as wireless Internet
surfing) work best with asymmetric traffic, since most of
the data goes from the Internet to the terminal
(transmissions from the terminal to the Internet are mostly
just "clicks").
This makes TD-SCDMA very similar to TDD-UTRA.
However, TD-SCDMA is also capable of supporting
larger cell sizes, similar to FDD-UTRA, while still
providing the data transmission advantages of a TDD
transmission mode. Data transmission and connecting to the
Internet are among the most important application scenarios
for 3G networks.
An additional advantage is that TD-SCDMA can re-use the
major part of the existing GSM networks. This makes
migration from a 2G to a 3G system for an operator easier
and with lower risks. In fact, the revenue streams can be
generated already during the transition phase, and not only
once the complete 3G network is up and running. So you
can say that it is a "true" on-top system for GSM.
Q: When will it become available? How is it superior to
other 3G technologies?
A : Firstly, it is still in the prototype stage. The first
working test bed will be available in Q1 2001, when it
will be offered to the operators for testing. TD-SCDMA
appears superior to some other 3G technologies, especially
W-CDMA (FDD-UTRA). These are especially with regard
to network planning, spectrum efficiency and mobile
Internet applications. With TD-SCDMA, the traffic
symmetry can be adjusted according to current demand in a
specific cell, so that voice (symmetric) or asymmetric
(Internet surfing) traffic can be optimized.
Elaborating, for TD-SCDMA, the cost of implementation is
much lower than that for any other 3G system. It is very
efficient in terms of radio spectrum, with 1.6MHz carrier
spacing -- either symmetric or asymmetric paired/unpaired
spectrum.
Q: What is the level of interest among the mainland
Chinese operators toward TD-SCDMA?
A : The mainland Chinese operators are very interested.
They are very independent, but nevertheless listen to what
the ministry of Information Industry (MII) says. We plan to
have the first trial system early next year. Mainland China
will adopt the system that is most advanced and suits them
best.
Q: So what compelled Siemens to jointly develop this
technology with the CATT?
A : In general, TD-SCDMA belongs to the mainland
Chinese part of Siemens. Therefore, operators will not
have to pay for the IPR (intellectual property rights) as it
has been jointly developed with the China Academy of
Telecommunications Technology (CATT).
There are around 32 million GSM subscribers in mainland
China. They need a 3G technology compatible with GSM.
Five standards have been specified for 3G. Of these,
W-CDMA (FDD-UTRA) and cdma2000 are the ones that
have been pushed the most. The operators are doing trials
on both and are looking for the best solution to suit their
needs.
TD-SCDMA and the TDD component of the UMTS
(TDD-UTRA) air interface are pretty similar. Our
engineers joined CATT to harmonize these two modes in
early 1998. That's when CATT and Siemens jointly started
developing TD-SCDMA.
Q: So what is the real reason behind Siemens putting its
weight behind the technology?
A : It is has always been Siemens' strategy to provide what
the market demands. Mainland China operators like both
W-CDMA (FDD-UTRA) and cdma2000, and Siemens will
also deliver its UMTS solution comprising W-CDMA and
TD-CDMA.
But they prefer a standard that is more tailored for the
mainland. Siemens will try and fulfil their needs. Right
now, however, it is too early to say either how many
licenses will be given away or how many operators will be
there.
Q: If this technology comes out, then what happens to
the so-called goal of a unified 3G standard?
A : Currently, there are several competing 3G technologies.
Under IMT-2000, you cannot, in fact, talk of a single
unified standard. It was clear early on in the 3G definitions
that there would have to be a family of standards, and that
each standard will be tailored to specific regional
requirements and preferences.
On the radio interface side, we have FDD-UTRA
(W-CDMA), TDD-UTRA, cdma2000, UWC-136 (often
called TDMA), DECT and TD-SCDMA. Additionally, you
have different network architectures depending on the radio
standard. Already, a really unified 3G standard would also
not be possible without TD-SCDMA.
Q: What sort of handsets will we be looking at, if and
when TD-SCDMA is up and running?
As far as handsets are concerned worldwide, you will
probably see multimode, multifrequency and multiband
handsets. There is a frequency issue involved, as there is
no global frequency band for 3G allocated yet. So we will
definitely have multimode handsets.
As for roaming, operators will probably make use of an
existing 2G technology for roaming. We will certainly see
next to normal voice terminals, and also terminals, which
group several functions in one device, such as a PDA, a
video terminal or an Internet surfstation. Don't forget that
one of the main applications for 3G is data transmission,
and in fact, much higher data rates will be possible with
3G, than with most desktop modems.
Q: If and when TD-SCDMA is allowed, what sort of
threat will Siemens pose to other leading network
vendors?
A : Siemens will certainly not remain alone in the
development of TD-SCDMA products. There is a lot of
interest not only from other network vendors, but also from
handset manufacturers, equipment tool suppliers and
semiconductor manufacturers. In fact, Nokia has already
shown strong interest in developing TD-SCDMA handsets
alone for mainland China with its huge market potential.
Siemens will develop TD-SCDMA handsets directly in
mainland China, together with a local company — in an
arrangement similar to CATT for the network. It can be
expected that these products will offer comparable feature
sets to the ones designed for other standards. Whether the
handsets will be dual- or triple-mode, it's too early to say.
It will probably be a GSM/TD-SCDMA handset, so that
will make a dual-mode handset an entry model. GSM will
be used to take care of the roaming part.
Q: What sort of opportunities do you see for
TD-SCDMA in the Asia Pacific and other areas?
A : It may suit a lot of other countries. That's up to the
operators. TD-SCDMA is especially interesting for those
countries looking for a smooth and risk-minimized
migration from 2G to 3G networks. Right now, mainland
China is mainly demanding this standard. If other countries
demand it too, we will provide it for them as well.
Q: And what sort of opportunities will it throw open for
the Asian makers of telecom equipment and
accessories?
A : We would like to have a lot of local development, so
that many products can be developed locally and, meet in
the best possible way, specific local requirements. First,
the standard has to be accepted by the operators on the
mainland. CATT and Siemens will like to include as many
parties as possible. We are talking with a lot of local
companies on the mainland. But it's still too early.
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