Heart & Soul feelH"
Lecture by Mr. Yoshiki Chika, General Manager, Engineering Planning
Dept., DDI Pocket, Inc. at the PHS Seminar on December 14, 2000 in Tokyo.
I would like to introduce the latest PHS service and a new series of terminals,
as well as our service expected for the coming year (2001). We will start
selling a new series of PHS terminals beginning in early December 2000
under the brand name feelH". Improving upon the conventional H"
series, feelH" aims to offer a service fully utilizing capabilites
to meet consumer expectations and to offer performance that more than
matches that of cellular phones. We are sure that this service will be
on par with those available from the IMT2000 service.
When we implemented a service last year (1999) called H"LINK (edgelink)
that provided WAP-like (email and Internet access-enabling) services,
such as high-speed handover and high-quality sound, we regained recognition
that "PHS could still be active". Through consumer evaluations,
we understood that that our service provided good quality for a reasonable
cost and provided a mobility that more than matched that of the cellular
80% of all H" users and 50% of all PHS users use mail services and
Internet access. For these points, DDI-P is seen as having the biggest
There are five major features of feel H", but the most common feature
for all terminals is the large color displays that are used. It is also
possible to send photographic images taken using digital cameras. For
the handling of sound data, MP3 files can be downloaded. Moreover, as
the diffusion of content using music (call-reception melody and "karaoke"
sing-alongs) is foreseen, high-quality LSIs and wide-range speakers are
used. Since there has been much competition in the wireless field including
cellular phones over the past year, and there have been many advertisements
trumpeting that fact that so many harmonic sounds are offered, we think
at this point in time that feel H" offers the most natural and quality
A camera that can be attached externally to all handsets offers 65,000
colors and 100,000 pixels, with the capacity of some 10KB per shot. It
is possible to take pictures of one's face as a portrait photo. Compared
with conventional mail that only sent text data, transmission of mail
with images and melodies will be possible from now on. With such a capacity
level, the cost of transmitting such data would be about the same as sending
text mail, so there is great merit in terms of tariffs and of enjoyment
of service at a reasonable cost.
The downloading of feel H" MP3s was made possible by the combination
of high-speed PHS downloading and reasonable tariffs. Although 64K downloading
by cellular phones is possible with cdmaOne, PHS makes downloading of
large volumes of data at reasonable tariffs possible.
Downloading time is as shown in Fig. 6-1 on the horizontal axis and tariffs
are indicated on the vertical axis. The red line shows the tariff for
PDC and the blue line shows the PHS tariff and the download time. The
numbers refer to the content volume. For example, a 100B short message
can be downloaded for one yen at an instant on cellular phones, with 1KB
of information being handled in about a second (a few yen). This is an
area where the small capacity of content can easily be downloaded in a
few seconds for a few yen.
Since everything starts at 10 yen for PHS, a small amount of mail would
cost 10 times more as compared to using a cellular phone. But the situation
is altered dramatically when downloading large amounts of data. For example,
downloading 10KB would take a cellular phone over 10 seconds (more than
10 yen) as opposed to PHS, which would take one second (10 yen). If the
capacity increased to 100KB, PHS would take 10 seconds (still 10 yen)
but some 100 seconds (several hundred yen) for the cellular phone.
As large content capacity is becoming the mainstream in the multimedia
field, the cost-performance of PHS can be promoted. For music downloading,
since a minute of music transformed to MP3 becomes about 1MB, one song
(roughly four minutes) would mean a download of 4MB. This download for
PHS would take from a few minutes up to 10 minutes, so it would cost about
a hundred yen.
Under the current PHS infrastructure, 64kbps circuit switching is offered
at 10 yen per minute, making music downloading reasonable in terms of
cost. On the other, at conventional costs it would be impossible for cellular
phones to offer service in this market, as it would cost a few thousand
Since the size of content from next year (2001) onwards will get bigger,
from 100KB to several hundred KB, such capacity can be offered by feelH".
Specific examples would be camera and MD sound.
Fujitsu Ltd. from last month (November 2000) started sales of a new personal
computer embedded with PHS, called LOOX. Conventional PCs only have a
PSDN modem internalized, whereas the rest were attached externally, but
LOOX has a PHS as well as an internal modem, so that the Internet can
be used as soon as it is purchased. This shows that customers are recognizing
that "for data communications and large-volume downloading via the
mobile environment, PHS is best."
The graph indicates the frequency efficiency ratio for PHS, cdma2000 and
other such systems. The vertical axis shows how many bits can be carried
for one cell at one Hertz per bit. On the right it shows PHS now and a
few years in the future, but it is much higher than for cellular phones.
Since the PHS cell size is smaller than for cellular phones, the actual
difference becomes even greater. Such technological background highlights
that PHS is cheaper not because of discounts but because of relatively
cheap tariffs in principle. Even if cellular phones go from digital to
3G, in terms of frequency efficiency ratio, the gap in price per bit would
remain. Therefore, as multimedia grows, it will provide a great business
opportunity for PHS.
The voice service user on average talks for about three hours per month.
For PHS, since H" is operated using 32kbps coding, by sending 32K
for three hours some 43MB can be downloaded. In contrast, since a variety
of coding is used for cellular phones, the average is some 5kbps coding
and a three-hour conversation equals a monthly download of some 7MB.
According to Internet service providers, the download amount of flat-rate
users each year is increasing, but is now about 30 to 40MB. Therefore,
if it is assumed that a full packet service is implemented, the network
capacity required for one voice user via PHS would be larger than the
amount needed by a flat-rate Internet user for now. Thus, as data communication
users grow more and more, PHS capacity would increase, and inversely the
grounds for lower tariffs would swell.
For a cellular phone voice user to fully utilize the Internet, the required
network capacity would need to jump by four to six times. Therefore, unless
the frequency efficiency ratio changes, the customer usability would fall
to one-fourth to one-sixth, and the tariffs would need to rise four to
six times. So for provision of very large-capacity service, it is better
to use PHS.
Next year (2001) packet service is scheduled to be introduced. The frequency
efficiency ratio compared with circuit switching is high, and is a service
very conducive to Internet use. Using this would be good mainly for application
such as AO/DI for Internet browsing. Since Internet browsing entails more
looking compared with downloading time, Internet resources are not being
used at all during the looking process. Thus, for this service the said
application's feature can be used to automatically switch to packet switching
while not downloading, when it is not looking at the HP.
On the other hand, for web page downloading, an immediate circuit switching-60
will enable efficient network use. If such efficient network resource
use can be realized, tariffs would become highly attractive to customers.
Although there will be a time lag, a higher speed service that bundles
several packet protocols is currently on the drawing board. Since PHS
can use four channels automatically on a wireless unit, four times 32K
means 128K, and if these could be bundled by fours, the wireless unit
could offer a speed of 512K. Although R&D is still ongoing at this
very moment to investigate how fast it can become, it is hoped that at
least 128K will be offered at an early stage. Moreover, after 2003, a
PHS system realizing a very high speed of 1MB can be foreseen.
Turning PHS into system components:
PHS is a very low powered system, as is well known. For data communications,
a PCM CIA card with an embedded wireless unit has been available for two
years, but a compact flash sized unit was put on sale by NTT DoCoMo just
last year (2000). In the future, the size is seen as falling into the
category of smart media or memory cards (memory sticks, SD cards, MMC
When this happens, PHS will no longer need to be the size of phone units.
If needed, PHS could be imbedded into watches or digital cameras. There
is a need to buy cellular or PHS phone terminals now, but in the future
PHS could become a small device that could be combined with the PDA of
choice: if carried in one hand the PDA would be called a phone, if larger
it would be called a PDA, perhaps. If held in both hands it could be called
a personal computer. The fact is that anything could become a PHS phone
unit, made possible by the low power consumption feature of the microcell
system known as PHS.
Herewith is introduced the activities to improve the PHS network quality.
PHS is a microcell system, so a neat network configuration (cell delineations
formed neatly) like cellular networks is not possible. What the customer
wants is a network that can be used anytime, anywhere whether inside the
home or a building or on platforms underground, even in resort areas.
PHS is aiming to establish such a network, but since the cell size is
small, various "uncovered holes" are to be found minutely all
over the area. If these can be found, a very low cost cell station can
be used to cover the hole, but unfortunately it is difficult to find such
Therefore, unless a new network management method is introduced, realization
of a network that can be used anywhere easily would be difficult. Our
company has a specialized team of several tens of people that has been
working to find the solution to this over the past several years, working
to improve network quality day and night.
The basic concept is to cover the regular life areas, in the home, at
the workplace and the means of transportation (roads or trains). So to
have the radio wave reach anywhere from Monday through Friday, and on
weekends, cover nearby shopping malls, and urban leisure facilities such
as Disneyland. Furthermore, in winter, the ski slopes and, in summer,
the beach and other far away resort areas as well as roads and trains
connecting these would be necessary. All fields need not to be covered,
but coverage of main areas visited by urban dwellers is the main policy
today. A marketing plan linked to this is aimed to improve customer satisfaction.
Introduction of a computer system and maintenance every month of the network
in several tens of fine items is being conducted. Looking at the parameters,
increasing antenna numbers in bad quality locations and tuning network
control parameters are being done.
For example, in cases where there is interference in a high-rise or ski
slopes across a mountain, we cover those locations by directing individual
antennas or using repeater systems. In rural areas, we have introduced
high-power stations that are proven to cover a radius of 5km. Now, PHS
can become a system for covering such areas.
Next year, our target is to achieve a transmission speed of 500kbps, resulting
in easy-to-use multimedia services within a reasonable price range.
Contact Person: Masaaki Hirose, Secretariat
Tel: +81-3-5510-8599 Fax: +81-3-3592-1103