Hi,
In response to Zeus, your problem is because Alcatel algorithm wants you to have Pref_Mark 0 i.e least prioritized for at least one TRX if GPRS / EDGE is enabled, and this is the TRX on which PDCHs would be allocated be it fixed or switchable.
You probably shifted PD to BCCH by changing its pref mark to 0 and Ps_Pref_Bcch_Trx. so automatically your GSM Calls are now disfavoured for this TRX.
What you can do is to define your BCCH on the max GSM TRX count available e.g TRX-4 if you have 4 TRXs keep all pref_marks at 0 then since alcatel uses back filling your BCCH would be preferred for both CS and PS.
This is one way around which you can use in B-9.
Hope it proves useful