Understanding the GSM specs

[David A. Burgess]

Nordin -

You will probably find GSM 04.07 Appendix B of some use here.   
Specifically, for a description of the padding sequence and the  
meaning of "H" and "L" see GSM 04.07 B.1.2.2.

-- David



On Jun 18, 2009, at 9:12 AM, Nordin wrote:

> Well guys,
>
> If someone can help me with how to fill in the Rest Octets, I'll  
> send you a postcard from my city to thank you :)
> What I found out is that it uses CSN.1 notation, but the  
> description is hard to follow, I began to see words floating around  
> the screen.
>
> <SI3RestOctet>::=<Optionalselectionparameters>
>            <OptionalPoweroffset>
>            <SystemInformation2terIndicator>
>            <EarlyClassmarkSendingControl>
>            <Schedulingifandwhere>
>            {L|H<GPRSIndicator>}
>            <sparepadding>:
>
>    <OptionalSelectionParameters>::=   L |H <SelectionParameters>;
>
>    <SelectionParameters>::=
>            <CBQ:bit(1)>
>            <CELL_RESELECT_OFFSET:bit(6)>
>            <TEMPORARY_OFFSET:bit(3)>
>            <PENALTY_TIME:bit(5)>;
>
>    <OptionalPowerOffset>::=        L |H <PowerOffset:bit(2) 
> >;<SystemInformation2terIndicator>::=
>        L|H;
>
>    <EarlyClassmarkSendingControl>::= L|H;
>
>    <Schedulingifandwhere>::= L|H <WHERE:bit(3)>;
>
>    <GPRSIndicator>::=        <RACOLOUR :bit(3)>
>                                            < SI13POSITION :bit>;
>
> So, now I want to enable GPRS support by do something with  
> GPRSIndicator. This is how I thought to do that:
> L|H -> 1
> next -> RACOLOUR -> 000
> next -> SI13POSITION -> 0
> So we get -> 1 000 0
>
> Next step is to do something with padding but than I'm lost. I  
> don't have good documentations on how to use CSN.1 for GSM network.
>


David A. Burgess
Kestrel Signal Processing, Inc.