Patent ID: 7339904

Claim:
A method of operating a communication device in a mobile communications network, the device operating using a protocol having a physical layer, a user layer and at least an RRC (radio resource control) layer and an RLC (radio link control) layer of a UMTS system, wherein the RRC layer is arranged to submit an SDU to the RLC layer for communication using the physical layer and thereupon to start a timer process in the RRC layer, the method comprising in response to said timer process reaching a predetermined timeout value: causing said RRC layer to resubmit said SDU to said RLC layer a predetermined number N of times, each time starting said timer process; and in response to N further instances of said timer process reaching its timeout value, causing said RRC layer to submit to said RLC layer an error message indicative of an unrecoverable error in said RLC layer for emission in response thereto.