GPRS slots

How do I select the number of up/down slots I want to use for a GPRS
connection?
i.e. how can I select 1 down and 4 up slots on a class 12 device? or
2+3 on a class 10?

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› See More: GPRS slots

> How do I select the number of up/down slots I want to use for a GPRS
> connection?
> i.e. how can I select 1 down and 4 up slots on a class 12 device? or
> 2+3 on a class 10?

You don't. The phone picks the appropriate slot combination in conjunction
with network slot availability.
-mark

So if I want my 5 slots to be 1+4 instead of 4+1 or 3+2 .... I can't.
If the network allocates something else then I'm stuffed. My
application needs to send at high speed - I dont care about the
download speed.
Is this something I can arrange with my network provider?

> So if I want my 5 slots to be 1+4 instead of 4+1 or 3+2 .... I can't.
> If the network allocates something else then I'm stuffed. My
> application needs to send at high speed - I dont care about the
> download speed.
> Is this something I can arrange with my network provider?

You may be able to rewrite your phone's software to do this, but thats about
as far as I can help you on the subject. AFAIK, the phone software
handshakes with the network, and the network is what allocates the slots.
If your program is only uploading, I would believe the network would
re-handshake with the phone to allow it, but GPRS has always been download
over upload.

-mark

Thanks Mark.
I have now found a few more references on the web.

It seems that some devices can be pre-set. I have found two that can be
setup to operate at the different slot count for class 12 - i.e. 4+1,
3+2, 2+3, 1+4. Obviously if these slots are not available then a lower
connection will be provided.

I have also found theories and proposals for dynamic slot allocation.
As far as I can tell, non of the UK operators implement a dynamic
scheme.

My provider has informed me that it is the modem that decides how the
slots are allocated. The modem manufacturer says it's the network
provider that decides.

So, I still cant decide on Class 10 or 12. If I go for Class 12 to
achieve 4 TX slots I may still only get 1 !!

GreenPig wrote:
> Thanks Mark.
> I have now found a few more references on the web.
>
> It seems that some devices can be pre-set. I have found two that can be
> setup to operate at the different slot count for class 12 - i.e. 4+1,
> 3+2, 2+3, 1+4. Obviously if these slots are not available then a lower
> connection will be provided.
>
> I have also found theories and proposals for dynamic slot allocation.
> As far as I can tell, non of the UK operators implement a dynamic
> scheme.
>
> My provider has informed me that it is the modem that decides how the
> slots are allocated. The modem manufacturer says it's the network
> provider that decides.
>
> So, I still cant decide on Class 10 or 12. If I go for Class 12 to
> achieve 4 TX slots I may still only get 1 !!
>

Hi guys,

to be blunt: the modem manufacturer is right. The phone/modem only
declares its capabilities (multislot class) to the network, and the
allocation of slots is totally up to the network. The allocation that
will be given depends on the phone/modem's capabilities (multislot
class, support of extended dynamic allocation), traffic conditions,
congestion (etc.), and the support of extended dynamic allocation in the
network side.

Also, it should be remembered that the amount of allocated slots can
(and usually does) change dynamically "on the fly".

NOTE: without the support of extended dynamic allocation in the network
(and the phone/modem), the maximum amount of uplink (i.e. phone/modem to
the network direction) slots that can be allocated is 2. Period. So,
having class 11 or class 12 in the device doesn't help at all if the
network (or the phone/modem itself) does not support extended dynamic
allocation.

For more information, see GSM specifications 05.02 (Annex B: multislot
classes) and 04.60 for the description on the allocation modes (Dynamic
Allocation, Extended Dynamic Allocation, Fixed Allocation: Fixed
Allocation is not supported by any network, and it has been since
removed from the later versions of the specifications. Dynamic
Allocation is supported by all GPRS networks, whereas Extended Dynamic
Allocation is not necessarily supported as of yet - at least in all
networks).

The specifications (R99 versions) can be found e.g. from

05.02 : http://www.3gpp.org/ftp/Specs/latest...s/0502-8b0.zip

04.60 : http://www.3gpp.org/ftp/Specs/latest...s/0460-8q0.zip

Oh, finally, using more than 1 (or 2) uplink slots will mean a
significant increase in the phone/modem power consumption. In practise
this means that hand-held terminals cannot (whereas PC cards etc.
perhaps can) do this amny slots without reducing the maximum output
power. This means that when the phone/modes gets farther from the base
station, the amount of uplink slots will likely be reduced by the
network or the connection will/may simply break up (at least at times).

Regards,
Antti

Thanks Antii - I think you've covered all the questions.

I have downloaded quiet a few specs fro the 3gpp site recently but I
must have spent hours yesterday just looking for this information.
Their search tool is a bit limited when it comes to finding just the
right documents. I could download all of them but they keep changing.

With your information I don't think I'll go for a Class 12 device.