System and method for avoiding stall using timer for high-speed downlink packet access system

A method of processing data blocks including packet data in a receiver of a mobile communications system, the method comprising:

• if a timer is not active, starting the timer for a data block that is correctly received, the data block having a sequence number higher than a sequence number of another data block that was first expected to be received;
• and
• when the timer expires,
• delivering to a higher layer, all correctly received data blocks among data blocks up to and including a data block having a sequence number that is immediately before the sequence number of the data block for which the timer was started,
• delivering to the higher layer, all correctly received data blocks up to a next not received data block, including the data block for which the timer was started, and
• re-starting the timer for a data block with a highest sequence number among the received data blocks that cannot be delivered to the higher layer.