UMTS ASC (Access Service Class)

[cd0ekj]

Dears,

In the procedure of initial Access to the UMTS network, the UE reads the BCH information and based on the ASC (Access Service Class) retrieve the subchannels he can use later to send the RACH preambule.

My question is how the ASC is retrieved? I suppose it's hard coded in USIM

BR,

[peanut]

Dear cd0ekj,

not exactly, the information present in the USIM is AC (Access Classe) and not ASC
In brief, the UE can read its AC from USIM then there is a mapping between AC and ASC send on the SIB5.

for your information:
There is 15 AC 0 to 9 for normal users, 10 for emergency calls, 11 to 15 for special users this is the same as GSM
There a maximum of 8 ASC.

BR,

[cd0ekj]

Thanks peanut for your prompt answer,

What's the benefit of having these ASC, why just only AC like old GSM?

BR,

[peanut]

Dear,

UMTS has improved many procedures in GSM, as an example the access procedure, which is much more complex than is pair in GSM.
this procedure use ASC instead of AC.

BR,