Mobile phone masts

I've been looking at http://www.sitefinder.radio.gov.uk/ and notice that
orange have littered my town with cells while the other networks can make do
with just one or two. It might be a dumb question but why is this? It's not
a large town and I get a reception where ever I am with only one cell!

Dan

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› See More: Mobile phone masts

[email protected] declared for all the world to hear...
> I've been looking at http://www.sitefinder.radio.gov.uk/ and notice that
> orange have littered my town with cells while the other networks can make do
> with just one or two. It might be a dumb question but why is this? It's not
> a large town and I get a reception where ever I am with only one cell!

They will be very low power microcells, more cells = more capacity.
Where as one BTS might cover the same physical area it can only handle
about 8 calls simultaneously. By having more cells the network becomes
much more robust and immune to failure.
--
Regards
Jon

"Dan" <[email protected]> wrote in message
news:[email protected]
> I've been looking at http://www.sitefinder.radio.gov.uk/
> and notice that orange have littered my town with cells
> while the other networks can make do with just one or
> two. It might be a dumb question but why is this? It's
> not a large town and I get a reception where ever I am
> with only one cell!

How do you know you are only using one cell..?

Ivor

"Jon" <[email protected]> wrote in message
news:[email protected]...
> [email protected] declared for all the world to hear...
> > I've been looking at http://www.sitefinder.radio.gov.uk/ and notice that
> > orange have littered my town with cells while the other networks can
make do
> > with just one or two. It might be a dumb question but why is this? It's
not
> > a large town and I get a reception where ever I am with only one cell!
>
> They will be very low power microcells, more cells = more capacity.
> Where as one BTS might cover the same physical area it can only handle
> about 8 calls simultaneously. By having more cells the network becomes
> much more robust and immune to failure.
> --
>

One "cell" can handle anything between 6 and 100-odd calls (possibly more I
suspect), depending on the configuration: How many "circuits" are installed,
the radio codecs used etc - then you can have multiple "cells" on one BTS.

However, you're otherwise completely correct - I'd be interested in which
town the OP saw this in. There's also the issue of in-building coverage,
which tends to attract street-level picocells and in-building "sites" to
serve.

I remember quite a few years ago, someone made the point that you could
cover central London with one or two well-sited BTS (on the BT tower, for
example) - but that you'd have air interface congestion in seconds, because
there is no way you'd be able to install sufficient capacity on one site
alone.

Regards

Jon.

--
Jon Pitts
Email: [email protected] Attachments: [email protected]

Jon Pitts wrote:

> I remember quite a few years ago, someone made the point that you could
> cover central London with one or two well-sited BTS (on the BT tower, for
> example) - but that you'd have air interface congestion in seconds, because
> there is no way you'd be able to install sufficient capacity on one site
> alone.

I remember a weekend in the late 80's when Cellnet and/or Vodafone did a
famous doubling of capacity by halving the areas their cells handled (or
something like that).

> One "cell" can handle anything between 6 and 100-odd calls (possibly more
> I
> suspect), depending on the configuration: How many "circuits" are
> installed,
> the radio codecs used etc - then you can have multiple "cells" on one BTS.
>
> However, you're otherwise completely correct - I'd be interested in which
> town the OP saw this in. There's also the issue of in-building coverage,
> which tends to attract street-level picocells and in-building "sites" to
> serve.

The town is Haverhill. Thanks for the replies.

Dan

"Colin Forrester" <[email protected]> wrote in message
news:[email protected]...
> I remember a weekend in the late 80's when Cellnet and/or Vodafone did a
> famous doubling of capacity by halving the areas their cells handled (or
> something like that).

Late eighties would be pre-GSM.

"Jon Pitts" <[email protected]> wrote in message
news:[email protected]...
> However, you're otherwise completely correct

Pray, please do tell us which bit was incorrect?

Clueless2 wrote:

>> I remember a weekend in the late 80's when Cellnet and/or Vodafone did a
>> famous doubling of capacity by halving the areas their cells handled (or
>> something like that).
>
> Late eighties would be pre-GSM.

Yes pre-GSM but how does that change my statement. Do you remember the
exercise?

I seem to recall having an NEC9a handset at the time and another fixed
handset in the car - money was no object in those days!

"Clueless2" <nospam@nospam> wrote in message
news:[email protected]...
> "Jon Pitts" <[email protected]> wrote in message
> news:[email protected]...
> > However, you're otherwise completely correct
>
> Pray, please do tell us which bit was incorrect?
>
>

> They will be very low power microcells, more cells = more capacity.
> Where as one BTS might cover the same physical area it can only handle
> about 8 calls simultaneously. By having more cells the network becomes
> much more robust and immune to failure.
> --
>

One "cell" can handle anything between 6 and 100-odd calls (possibly more I
suspect/believe), depending on the configuration: How many "circuits" are
installed,
the radio codecs used etc - then you can have multiple "cells" on one BTS

Regards

Jon.

--
Jon Pitts
Email: [email protected] Attachments: [email protected]

"Jon Pitts" <[email protected]> wrote in message
news:[email protected]...
> One "cell" can handle anything between 6 and 100-odd calls (possibly more
> I
> suspect/believe), depending on the configuration: How many "circuits" are
> installed,
> the radio codecs used etc - then you can have multiple "cells" on one BTS

OP specifically stated that one BTS can carry 8 traffic channels. Was that
incorrect?

On Thu, 7 Sep 2006 23:12:24 +0100, "Clueless2" <nospam@nospam> wrote:

>OP specifically stated that one BTS can carry 8 traffic channels. Was that
>incorrect?

Eight traffic timeslots per channel. There can be many channels in a
cell sector. (a BTS may have one or more sectors).

OTOH, it is possible that not all 8 timeslots will be available in a
coastal or very remote base.

So it's unlikely there will be fewer than four slots per cell, and
unlikely there will be more than 96.

So "eight" is not always correct. But it's not a bad starting point.

--

Iain
the out-of-date hairydog guide to mobile phones
http://www.hairydog.co.uk/cell1.html
Browse now while stocks last!

On Fri, 08 Sep 2006 22:27:58 +0100, [email protected] wrote:

> [re-ordered]

Excellent post, hairydog, as ever. In case readers are interested,
can I offer some detail?

>Eight traffic timeslots per channel. There can be many channels in a
>cell sector. (a BTS may have one or more sectors).
>
>OTOH, it is possible that not all 8 timeslots will be available in a
>coastal or very remote base.

As she says, there are 8 slots per channel. On the first channel on a
sector, 2 timeslots are used for GSM voice & SMS. If SMS traffic is
extraordinarily high (creating huge amounts of signalling taffic) then
a secondary signalling channel (SDCCH) will be reserved, leaving only
5 channels for GSM voice on the first sector. Each channel can only
support one active call. Though many, many, attached mobiles can be
supported - they use the signalling channels, not the voice channels
except when they are in an active call.

In a remote district there may only be a single sector (sometimes
called an OMNI), and only a single channel - one 200kHz band - out of
the frequency allocation.

But GPRS requires more capacity on the channel reserved for itself,
and hence denied to voice. GPRS requires a minimum of a single
timeslot on each sector - it is consumed by the PDCH slot. GPRS
traffic can occupy idle GSM voice timeslots, so another channel is not
normally reserved for GPRS in most networks. But if there is a need
for GPRS traffic to have more reserved capacity, aother GPRS timeslot
can be reserved, and denied to GSM voice.
>
>So it's unlikely there will be fewer than four slots per cell, and
>unlikely there will be more than 96.
>
Taking the minimum signalling (2), and GPRS (1), then unlikely there
will be more than 93. But in terms of traffic capacity, it's not
really a material difference, so using 96 as an approximation is
reasonable.

>So "eight" is not always correct. But it's not a bad starting point.
>

Exactly. For people working in the networks, who have to worry about
capacity handling at peak times, they know that it's really 5 or 6 on
the first channel, and 8 on subsequent channels (and each channel
costs an expensive TRX, as well as the backhaul to the BSC/MSC), but
the rest of us can approximate.
>
>Iain

>the out-of-date hairydog guide to mobile phones
yes, it is, rather. ;-)


______________
best wishes,
Ron

On Fri, 08 Sep 2006 22:11:10 GMT, [email protected] (Ronnie) wrote:

Sorry, missed out two vital words:

>On the first channel on a
>sector, 2 timeslots are used for
.... control of ...
> GSM voice & SMS.

Fairly vital. The remaining channels can be used for voice calls.
Apologies to those I must have confused.

______________
best wishes,
Ron

"Ronnie" <[email protected]> wrote in message
news:[email protected]...
> On Fri, 08 Sep 2006 22:27:58 +0100, [email protected] wrote:
>
> > [re-ordered]
>
> Excellent post, hairydog, as ever. In case readers are interested,
> can I offer some detail?
>

>
> >So "eight" is not always correct. But it's not a bad starting point.
> >
>
> Exactly. For people working in the networks, who have to worry about
> capacity handling at peak times, they know that it's really 5 or 6 on
> the first channel, and 8 on subsequent channels (and each channel
> costs an expensive TRX, as well as the backhaul to the BSC/MSC), but
> the rest of us can approximate.
>

True - but there are also different interpretations of what a "BTS" is -
whether you're talking about the sector itself, or the "mast site" as is
possibly more conventional. I tend to think of a BTS as the sector itself,
which was where I was coming from.

There's also HR/AMR coding that can double the voice capacity of a TRX, but
admittedly all this is picking holes in a very well explained post.

Regards

Jon.

--
Jon Pitts
Email: [email protected] Attachments: [email protected]