Patent ID: 8355331

Claim:
A method comprising: processing, by a PDCP (Packet Data Convergence Protocol) entity located between upper layers and lower layers of a radio interface protocol stack, PDCP data units received from the lower layers after a PDCP re-establishment is requested from the upper layers; compiling, by the PDCP entity, a PDCP status report by, setting an FMS (First Missing Sequence number) field to a PDCP sequence number (SN) of a first missing PDCP SDU (Service Data Unit), if there is at least one out-of-sequence PDCP SDU stored, allocating a bitmap field of length in bits equal to the number of PDCP SNs from and not including the first missing PDCP SDU up to and including a last out-of-sequence PDCP SDUs, rounded up to the next multiple of 8, indicating a ‘0’ in corresponding positions of the bitmap field for all PDCP SDUs that have not been received as indicated by the lower layers, and indicating a ‘1’ in corresponding positions of the bitmap field for all other PDCP SDUs; and sending, from the PDCP entity to the lower layers, the PDCP status report as a PDCP PDU (Protocol Data Unit) for transmission to a peer PDCP entity at a receiving side.