In article <telecom24.347.11@telecom-digest.org>, jhedfors
<jhedfors@gmail.com> wrote:
> I wonder if such a device is feasible?
> Could there be a device that gives give off a home network signal that
> your cell phone can connect to as it does your service provider? You
> could then user your cell handset for VOIP calls when near such a
> device.
> There is talk of special wi-fi enabled phones doing this, but this
> could be used with any phone, and could possibly be wi-fi enabled as
> well.
> Any thoughts?
"Feasible"?? H*LL NO!!
It would be a commercial transmitter. This requires FCC 'type
acceptance' or (in special cases) acceptance testing of the specific
transmitter. Costs are in the high-5-to-middle-6-figures left of the
decimal point.
A FCC station _license_ for that device would also be required. The
costs for generating the supporting data needed for the license are
'non trivial', to put it mildly.
That's _before_ considering the 'design' costs of such a device.
That's going to be _another_ high-5-to-middle-six-figure amount --
DESPITE the fact that you can use the basic design of a standard cell
station. You have to have 'something' to replace the functionality
for determining which cell answers a call, 'validating' the phone,
managing inter-cell hand-off, etc. Even if you're not using the
particular facilities for call management, you have to provide the
basic 'control' functions to the cell station for *it* to operate
properly. There's a *lot* of software to design/build/test, for
'emulating' the un-needed/un-used head-end functions required by a
standard cell base-station.
Next, you've got the tooling and start-up costs for the production
line to build the d*mn things.
Direct manufacturing cost is going to be in the low hundreds of
dollars, *minimum*. Plus 'overhead' costs -- things like advertising,
etc. Plus something towards recouping the 'development' costs
mentioned above. Plus distributer/wholesaler mark-ups.
If you peg the total development/start-up cost at 'a few million
dollars', you have to sell a few thousand of these devices a year,
_at_a_PROFIT_ of over $100/unit, just to cover 'debt service' on the
development costs.
Totalling: several hundred manufacturing cost, minimum $100 for debt
service, plus 'something' towards retiring that debt, plus 'overhead'
-- mgmt, marketing, etc., plus distribution costs -- I don't see _how_
such a device could carry a 'street' price much below $1,000 (probably
_considerably_ higher). Considering that the buyer also has all the
expenses of getting that FCC station license, I really question
whether the sales of 'several thousand units/year' that the
debt-service figure was predicated on is reachable. If the market is
only 10 units/year, then you've got to get circa $10-25,000 per unit
_just_ for the 'debt service'.
After all that, there is the 'minor' issue of how that base station
'knows' what the particular phone's "home network" _is_. and how to
send the right 'magic incantations' associated therewith.
*AND* the matter of either 'co-ordinating' with the "real" cell-tower
network so that call-handling is 'handed off' to this device, *or* of
providing an over-riding signal such that the phone 'cannot see/hear'
the real network when in range of this device. In the latter
scenario, you have a *major* problem in ensuring that the "effect" of
your base-station doesn't extend to anybody else's phones -- going by
outside. (Not to mention the 'minor matter' of it being illegal to
intentionally interfere with the transmissions of another licensed
station. <wry grin>)
*AND* the "problem" that arises when two people -- in adjacent
apartments, say -- *both* try to install such a device. and one
person finds that in half his apartment, he's "closer" to the other
person's base station than he is to his _own_ station. Oh, yeah, their
phones are both on the same 'real' carrier, so you can't even
differentiate by 'home' network.
To make this idea "workable" -- in a theoretical sense -- you'd need
to re-design the cell *phone* itself. with a separate "mode" of
operation, where it locked up to this 'private' base-station, and made
no attempt to query the "common-management" and/or use an alternate
cell with a "better" signal.
If there is *one* thing that this 'crazy idea' is not, that thing is
'feasible'! "Feasible" means 'practical, from a _financial_ point' --
and 'finances' do look to be a real 'killer' for this project. Not
the only one, but a killer nonetheless.
Robert Bonomi (bonomi@host122.r-bonomi.com)