RE: stds-802-mobility: Hand-off question
Title: Message
Interesting question.
Surely
a 'mobile' system must support roamiong and handoff by definition ?
Unless
the expectation is that 802.20 will be ubiquituous & seamless from launch
(unrealistic given coverage, site acquisition difficulties, and current
financing situation?), then that implies handoff to other
technologies.
Consider a user experience. They are in the middle of a 802.20 session,
then leave the coverage area... Without handoff, the session breaks
and the user will likely regard that as a failure. What is more, you could argue
that broadband services tend to be less tolerant of interruptions than
narrow-band ones - the user could be watching a (paid-for) video-session, or be
in the middle of a VoIP call, or a major file synch - all of which would be
annoying to drop.
Now
consider it from an operator's perspective. That user has lost their session
(involuntarily, not a good thing for service reputation). Either they will give
up (and read a book), or they will restart, probably using a technology which
they believe will have coverage & reliability - 3G, 2.5G etc. Once they are
connected to that, if there is no mechanism to return them to MBWA the operator
has essentially lost that customer until (unless) they initiate the
transition.
While
not all operators will support two-way handoff (drop back to 3G; lift-up to
MBWA) some certainly would like it. I would suspect that any operator
launching MBWA would want a drop-back optioon in ordder to offer seamless
service (for a new entrant, they'd negotiate a wholesale or MVNO deral with an
incumbent).
To
David's question, the fact that MBWA offers higher performance than 3G is
somewhat beside the point: it is very common for newer, better, standards
to default to another (slower) if required.
For
example, 3G drops back to 2G. (The lack of this capability at launch was
one of the major reasons for DoCoMo's problems with FOMA).
Similarly, V.90 can drop back to V.34 or slower; 100baseT interoperates
with 10baseT, etc etc
To
turn the querstion around: if MBWA does *not* support handoff, then
it is essentially a hot-spot application. As such, what will be the usage cases
where it delivers better customer experience than 802.11
?
What could be the
purpose ? MBWA is just that - truly broadband, not 3G at
all.......
Will handoff be supported between 802.20 and
public 3G?