Stay in Standby despite was ready before

Hi All,

I am from PS,
But I have a ticket from first line that I can’t solved because for me the problem is on the ACCESS part:
One user is able to connected to network through GPRS, so he has his PDP context, so he has his IP address he is entering in ready state but when he stop sending information, his state is going to idle but impossible for him to come back to ready when he wants to transmit info,
If we try to send info, it seems that he is not answering the paging.
He still have its pdp context (IP adress in the core) but Impossible to ping this MS from the core.
the same customer has an other equipment from home and same problem occurs (it is an other BSC, but located in the same area)
For me the problem is coming from the access, What do you think ?.
I encountered a similar case before in an other operator, and we have just to reboot a PCU card and the problem was solved. But it seems here the problem occur in two BSCs (that is why the first line think the problem came from the Core) but in the same area
Did someone encounter the same case before ?
Could you confirm me that this problem is coming from the ACCESS part.
Thank you very much