Patent ID: 7769926

Claim:
A method for providing a buffer status report in a mobile communication network, which is implemented between a base station and one or more user equipments for providing the user equipments to report buffer status of the user equipments to the base station, wherein each user equipment has multiple logical channels divided into a plurality of logical channel groups (LCGs), each logical channel group corresponds to a buffer and a buffer status of the buffer, and each logical channel has a priority, the method comprising the steps of: (A) having an arrival data to a buffer of the user equipment and the priority of a logical channel for the arrival data higher than those of other logical channels for existing data in the buffers; (B) triggering a buffer status report (BSR) associated with the buffers of the LCGs that contain data in the buffers; (C) using the user equipment to calculate available space of a Protocol Data Unit (PDU) to be transmitted based on resources allocated by the base station to thereby determine whether the available space of the PDU to be transmitted is enough for filling all data of the buffers of the LCGs and a short buffer status report, wherein the short buffer status report provides the buffer status corresponding to a single logical channel group (LCG), and the short buffer status report comprises a LCG identification (ID) field and a variable granularity buffer size field, the LCG ID field indicates the single LCG corresponding to the buffer status, and the variable granularity buffer size field indicates all available data amount of all LCs of the single LCG by means of different granularities; (D) using the user equipment to transmit the short BSR corresponding to the buffer of an LCG when only the buffer of the LCG has remaining data; and (E) using the user equipment to transmit a long BSR when the buffers of multiple LCGs have remaining data.