From my home in San Jose, CA, USA, frequently when I want to make a call, I
get "No Service". If I sit and wait -- sometimes seconds, usually less than 1
minute -- I get 3 or more bars of signal strength and can make a call. This
happens regularly, many times a day. (This is not after powering on the
phone, but when the phone has been on for hours.)
Once a connection is made, the call is good; very infrequently is my call
dropped.
What's the technical reason for this experience? If it were as simple as a
truck on the street blocking my line-of-sight to the nearest cell tower, that
couldn't be frequent enough to cause my "No Service" experience. If it was
general road traffic, it shouldn't occur with such regularity and I shouldn't
be able to maintain a call without dropping, should I?
> T-Mobile, Nokia 6200.
>
> From my home in San Jose, CA, USA, frequently when I want to
> make a call, I get "No Service". If I sit and wait --
> sometimes seconds, usually less than 1 minute -- I get 3 or
> more bars of signal strength and can make a call. This happens
> regularly, many times a day. (This is not after powering on
> the phone, but when the phone has been on for hours.)
>
> Once a connection is made, the call is good; very infrequently
> is my call dropped.
>
> What's the technical reason for this experience? If it were as
> simple as a truck on the street blocking my line-of-sight to
> the nearest cell tower, that couldn't be frequent enough to
> cause my "No Service" experience. If it was general road
> traffic, it shouldn't occur with such regularity and I
> shouldn't be able to maintain a call without dropping, should
> I?
Standard GSM is limited to 35 km (about 22 miles) range.
If you're in an area with few cells, this distance limitation
can cause the effect you're seeing. There'd need to be a
distant cell presenting a strong signal to your phone (probably
well elevated), with a closer, but usable, cell presenting a
weaker signal.
Then the phone is unable to interact successfully with the
distant cell. They'd be failing to negotiate a usable figure
for Timing Advance (TA in the range 0 to 63). The phone would
then find the weaker cell and register with that instead.
Assuming that the stronger cell is broadcasting the same
cellular Location Area Code (LAC) as the weaker one, your phone
is permitted to then camp on the stronger cell without any
interaction with it. And it would do so.
Any interaction with the distant cell would result in the
temporary "no service" outcome, as TA negotiation fails. There
are three scenarios which would trigger this: an incoming call
or SMS, an outgoing call or SMS, and an automatic periodic
location update (the timer value is set by the network).
If the above analysis is the correct one for your situation,
then your carrier could solve it for you by changing the LAC
for one of these cells, but you'd find your battery would
discharge much more rapidly because of frequent registration
attempts with the distant cell.
> Standard GSM is limited to 35 km (about 22 miles) range.
>
> If you're in an area with few cells, this distance limitation
> can cause the effect you're seeing.
I'm near downtown San Jose. I presume there's more towers around here than in
the rest of the state! (c:
Seriously, this is a major metro area, and yes, I'm sure there's lots of them
all around. Within a mile on either side of me there's 2 major thoroughfares
and 2 major freeways. Lots of towers.
Does this change your idea of what might be my problem?
> I'm near downtown San Jose. I presume there's more towers
> around here than in the rest of the state! (c:
>
> Seriously, this is a major metro area, and yes, I'm sure
> there's lots of them all around. Within a mile on either side
> of me there's 2 major thoroughfares and 2 major freeways. Lots
> of towers.
>
> Does this change your idea of what might be my problem?
Yes. I've seen the symptoms you describe only in a more rural
setting. The cells in question were broadcasting their
geographical names (as cell broadcast messages), so working out
what was going on was quite straightforward.
In your case then, I presume you're coming up against some
network configuration, propagation and/or firmware issues, but
I'd be just speculating about the exact nature.
On Sat, 9 Dec 2006 12:46:55 -0800, John E. <incognito@yahoo.com>
wrote:
>John Henderson sez:
>
>> Standard GSM is limited to 35 km (about 22 miles) range.
>>
>> If you're in an area with few cells, this distance limitation
>> can cause the effect you're seeing.
>
>I'm near downtown San Jose. I presume there's more towers around here than in
>the rest of the state! (c:
>
>Seriously, this is a major metro area, and yes, I'm sure there's lots of them
>all around. Within a mile on either side of me there's 2 major thoroughfares
>and 2 major freeways. Lots of towers.
>
>Does this change your idea of what might be my problem?
>
>Thanks,
The question is are the nearby tower the ones with transmitters from
your service provider on them?
I'm jumping in here 'cause you seem to actually know something about
these things work .
I'm using a Nokia 6820 in mid town Manhattan - which should be cell
heaven - and getting a slightly different behavior. If I'm in and out
of a no-signal zone (like the subway), the phone will not re-acquire a
signal. Yesterday I stood in the middle of Rockerfeller center looking
at zero bars for 20 minutes - well I was doing other things also....
A techie at Verizon advised me to reboot the phone when this happens -
turn it off, remove the battery and SIM, wait a few seconds then put it
back togeather and turn it on. This does work - BUT THERE'S GOTTA BE A
BETTER WAY!
> If I'm in and out
> of a no-signal zone (like the subway), the phone will not re-acquire a
> signal.
> A techie at Verizon advised me to reboot the phone when this happens -
> turn it off, remove the battery and SIM, wait a few seconds then put it
> back togeather and turn it on. This does work - BUT THERE'S GOTTA BE A
> BETTER WAY!
Power it off and on with the power button?
That worked with my ancient Nokia 8290 which had the same problem.
> This could be the issue. If you pick up your phone from the pocket, it could
> easily have lost service while it obtains "several bars" when held up in the
> hand. I'm not sure if OP observed the behaviour when the phone was e.g. on
> the table, and no persons "shielding" it.
The phone is lying on a desk just inside the glass-paned front door to my
home office. If I want to make a call, I pick it up and hold it many
different ways, hoping for better signal. If I have "No service" displayed,
how I hold the phone seems to make no difference; service will return
regardless where I'm holding it.
> The above "signal fading" could
> happen on 900 too but normally (at least European) networks have so strong
> coverage at 900 that it is difficult to find a fringe edge of a cell. Anyway,
> at the edge of the coverage and inside, one may easily have a signal strength
> change from "no bars" to "a few". The fact that OP had hardly any dropped
> calls "could" be from the better phone position during the calls. But the OP
> seemed to have analysed the case quite a lot and a simple answer like this
> may not be sufficient.
As far as I can tell, orientation doesn't seem to make a difference. It *is*
possible that moving the phone does cause better reception, and that this
takes several seconds to register and for the display to update the signal
strength indicator. But I have no way to know this. As far as my experience
has shown me, there is not connection between phone orientation and signal
strength.
> As far as I can tell, orientation doesn't seem to make a
> difference. It *is* possible that moving the phone does cause
> better reception, and that this takes several seconds to
> register and for the display to update the signal strength
> indicator. But I have no way to know this. As far as my
> experience has shown me, there is not connection between phone
> orientation and signal strength.
The phone will have an algorithm when in a no-signal condition,
to check progressively less frequently (up to a point). This
is to conserve battery, because scanning for an acceptable
network is more "energy intensive" then simply camping on the
strongest cell (and periodically monitoring a fixed number of
neighbouring cells) of an already-registered (and visible)
network.
For this to be the explanation, you'd need to be in an area of
marginal reception where the position of the handset is fairly
crucial.
There could be a number of factors working together against you,
such as some firmware algorithm only marginally adapting to
unusual local conditions. How does the phone behave elsewhere?
> I'm using a Nokia 6820 in mid town Manhattan - which should be
> cell heaven - and getting a slightly different behavior. If
> I'm in and out of a no-signal zone (like the subway), the
> phone will not re-acquire a signal. Yesterday I stood in the
> middle of Rockerfeller center looking at zero bars for 20
> minutes - well I was doing other things also....
>
> A techie at Verizon advised me to reboot the phone when this
> happens - turn it off, remove the battery and SIM, wait a few
> seconds then put it back togeather and turn it on. This does
> work - BUT THERE'S GOTTA BE A BETTER WAY!
I had a Motorola cd928 which would get itself into a state
sometimes where it would never find a signal again, not even in
days, until physically switched off and on again.
This was clearly a bug, but Motorola would never respond to my
queries about the problem, or a firmware upgrade.
It's really a question of experimenting to find the minimal
steps that will jolt it back to life quickly. Perhaps a
"network search" or "choose new network" (but selecting the
existing one) from the networks menu might be easiest if that
works, especially if you can set that up on a key or user menu
(I'm not familiar with that phone).
On some phones, you can set the automatic network search speed
to fast or slow. Fast search should reduce this problem at the
expense of battery life.
Doesn't a simple switch off/on fix it? If not, I'd call it a
bug.
>I'm jumping in here 'cause you seem to actually know something about
>these things work .
>
>I'm using a Nokia 6820 in mid town Manhattan - which should be cell
>heaven - and getting a slightly different behavior. If I'm in and out
>of a no-signal zone (like the subway), the phone will not re-acquire a
>signal. Yesterday I stood in the middle of Rockerfeller center looking
>at zero bars for 20 minutes - well I was doing other things also....
>
>A techie at Verizon advised me to reboot the phone when this happens -
>turn it off, remove the battery and SIM, wait a few seconds then put it
>back togeather and turn it on. This does work - BUT THERE'S GOTTA BE A
>BETTER WAY!
>
>Any ideas??
>
>BC
Probably not. Looking for a BTS is fairly hard on a battery, so when
you take the phone into an area without service, it tries a few times
quickly to locate another BTS. After that, it may be 10-20 minutes
before it decides to look again. It is a way of saving battery power.
I used to see that problem in rural Australia. I'd drive right by a
tower, and still see 'no service'. Power the phone off, power it back
on, BINGO!
> I used to see that problem in rural Australia. I'd drive
> right by a tower, and still see 'no service'. Power the phone
> off, power it back on, BINGO!
I can certainly confirm the extreme manifestation of that
behaviour when the reason for the "no service" is an initial
contact with the BTS at greater than 35 km. In the absence of
another BTS, some phones don't try the TA-fail BTS again in the
time it takes to drive the 70 km across its usable range.
I've assumed that this is a result of firmware that's designed
for more populous locations.
My nokia 6256 has been rebooting for no apperent reason when I unplug it
from the charger and close the lid. It's happened like 2 times in the
last 2 days.
--
"Egun On, Lagunak" (Basque for g'day Mates)
Pete Nalda
--
"Egun On, Lagunak" (Basque for g'day Mates)
Pete Nalda
--
"Egun On, Lagunak" (Basque for g'day Mates)
Pete Nalda
>A techie at Verizon advised me to reboot the phone when this happens -
>turn it off, remove the battery and SIM, wait a few seconds then put it
>back togeather and turn it on. This does work - BUT THERE'S GOTTA BE A
>BETTER WAY!
There should be, but.......
On my Palm Treo 650 (GSM) I have the same issue, and I have to do a
power off/on routine, especially when roaming overseas and trying to
acquire a carrier for the first time.
In fact Palm recommend this if there is a problem obtaining a carrier
after turning the phone on, whether roaming or not. Power off again,
then on.
.
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