Method of generating a buffer status for a wireless communication system and related device

A communication device of a wireless communication system for accurately generating a buffer status of a packet data convergence protocol, hereinafter called PDCP, layer, the communication device comprising:

• a processor for processing storage data;
• a communication interfacing unit for exchanging signals with a peer communication device of the wireless communication system;
• a control unit coupled to the processor and communication interfacing unit, for controlling the communication interfacing unit and the communication device according to processing results of the processor;
• and
• a computer readable recording medium coupled to the processor, for storing the storage data;
• wherein the storage data comprises:
• program code for including volume information of packets, which have been submitted to a layer lower than the PDCP layer and have not been confirmed by the layer due to buffer clearing of the layer, or have not been confirmed by a PDCP status report, in a buffer status report.