On Monday, July 8, 2002, at 02:00 , Ken Chang wrote:
<about WLAN and PHS>
> - neither have hand-off (we can discuss later)
both have hand-off (albeit far less complex that cellular systems)
I have built WLAN's which do hand-off from one to another base (where
you even keep you IP address and traffic in progress while hand-off
takes place is not negatively impacted). This comes out of the box with
each Airport base.
PHS, too does hand-off up although the maximum speed you can move at
while a call is in progress is somewhere around 100Km/h (originally it
was 40 Km/h).
> - neither can have full coverage
There is no such thing as full coverage. There is not a single PDC nor
GSM, nor CDMA network on the planet with full coverage of any country.
Even satellite doesn't have full coverage although it comes pretty close.
More importantly, there is no point in having "full coverage" - It is
simply a matter of "how much premium are you willing to pay for the odd
chance you may want to call from Mt.Everest".
> about the differences
>
> - companies will use WLAN and not PHS for LAN access.
Why are you so limited by your own perception ? Data as a driver for PHS
in Japan is an odd outcome of a very odd situation which is only present
in Japan, but nowhere else. Namely, the Japanese government forcing the
PHS operators to make a loss on voice. Because of an oddball government
conflict of interest situation, PHS companies in Japan are not allowed
to make any money on voice. Therefore, the only chance for them to
become profitable is to focus on data.
In China, PHS operators do not face such a dilemma and they are focusing
on voice, hardly any data services at all. Yet they are profitable at
rock bottom prices and PHS is the most popular mobile phone system
(competing with both GSM and CDMA).
> this makes
> good advantage for the WLAN market that, if enough hot-spots,
> everyone will only invest in and use WLAN instead of PHS, that
> the PHS subscription may dive like a stone.
We shall see. I predict that PHS technology will outlive PDC. It will
take a long while before we will see this, because both technologies
will be around for years and years to come, but PDC will take a dive
before PHS does.
Besides, where is WLAN in the VHE market ? PHS is the only technology
that can deliver VHE seamlessly and affordably. There aren't even any
white papers out for VHE using WLAN. PHS manufacturers have been
shipping cheap VHE solutions in millions of units during the last 5 or
six years all over the world.
> accually, WLAN and PHS competes in the same market segments -
Oh yes ? Ask a village monk in Thailand whether he'd consider a WLAN
base, ask a worker in China, a farmer in Bangladesh, villagers in remote
communities all over South America. Nobody will want WLAN because it
would be absolutely useless for them. However, they will all recognise
PHS as a blessing that has brough telephony to their communities.
> those who use computers extensively in the office and at home.
That's just one application in just one country. Even then, there are
plenty of PHS users in Japan who use it because of VHE and not data.
> ... and you can say we won't need public WLAN in Japan at all.
I never said that. I said that there are always various alternative
technologies which overlap in certain applications. Coexistence is the
word !!!
> - the WLAN access points can reverse-bill the service providers,
Not at present. there are no standards for inter-connect billing, none
for clearing and none for settlement. Nothing that could not be overcome
eventually, but right now there is nothing and it will take a long time
before there will be a viable standard.
> - WLAN is a world, oops, US standard and the chips and equipment
> will be cheaper than PHS (several million yen for a 3 channel
> basestation?).
That would be the pricing for a GSM pico-cell base. PHS can be had
starting at about 10% of that. UT Starcom's PHS system is very cheap,
around 1000 USD per unit at volume, IIRC. And with it you get QoS,
which you don't get with 802.11b, BTW.
> - also as a standard, you can have one card to use anywhere and
> access any service provider,
Only if you happen to be in the right place *and* signed up for a
multitude of monthly subscriptions, ...
> as opposed to PHS
... where you sign up with one operator and coverage is pretty much
everywhere.
> (though it's
> a non-brainer to choose H").
Q.E.D.
> same for roaming/abroad use.
Actually, the Taiwanese PHS users who are using the new roaming service
will find it far easier to use PHS data service while roaming over here
than they will with WLAN and it will take a long time before we will see
WLAN in the context of international seamless roaming (emphasis on
seamless).
> - the Japanese regulators make more hassles than yakuza, and
not quite sure what your point is.
> I'd not say it's a demerit if WLAN is not treated as telecom
you didn't - Curt and I did. And we have provided good reasons to back
it up.
> service, which will make it cheaper and easier to roll-out.
Misperception. You can't just look at the price tag at Sofmap in
Akihabara when you buy the base. You have to look at the overall cost.
Particularly the cost of inter-operator settlement is likely to be
horrendous. Not to mention the cost of missing QoS.
regards
benjamin
Received on Mon Jul 8 11:04:29 2002