Method and device for processing packets by packet data convergence protocol (PDCP) layer

Abstract

The invention provides a method and a device for processing packets by a PDCP layer. After receiving a protocol data unit (PDU), the PDCP layer on a receiving end compares the values of a PDU serial number and a next PDU serial number expected to be received of state variables, determines whether the PDU is a normal pocket or an out-of-order pocket according to the comparison results; if the PDU is the out-of-order pocket, the RX_HFN is kept not to be changed, and the SDU formed by the PDU is discarded; if the PDU is the normal data pocket, whether the serial number of the PDU is overturned or not is further judged, if yes, the value of the RX_HFN is added by 1, and the SDU formed by the PDU is submitted to an upper layer; if no, the value of the RX_HFN is kept not to be changed, and the SDU formed by the PDU is submitted to the upper layer, thus maintaining synchronism of the RX_HFN on the receiving end and the RX_HFN on transmitting end, and ensuring that the data transmission can be carried out smoothly.

Description

technical field [0001] The invention relates to data processing technology in the field of network communication, in particular to a method and a device for processing data packets at the Packet Data Convergence Protocol (PDCP) layer. Background technique [0002] In the Long Term Evolution (LTE) system, the data transmission of the mobile terminal in the handover process between base stations or the Radio Resource Control (RRC) process is implemented by the PDCP layer. The main task of the PDCP layer to process the received data is to maintain the state variables of the receiving end, so that the receiving end hyperframe number (RX_HFN) recorded by the receiving end is consistent with the sending end hyperframe number (TX_HFN) so that the received PDCP protocol The data unit (PDU) is correctly decrypted to ensure smooth data transmission at both ends of the transceiver. Among them, the state variables maintained by the PDCP layer usually include: the next PDU sequence numbe...

AI Technical Summary

Problems solved by technology

In this process, the PDCP layer at the receiving end only performs reordering and deduplication processing on the SDUs in the reordering window within the timing duration of the Flush timer. However, since the receiving end cannot accurately know the time required to receive out-of-order PDUs, Therefore, it is difficult to accurately set the timing duration of the Flush timer. If the Flush timer times out and the out-of-order data generated during the switching process has not been processed, then under normal circumstances, if the value of Next_PDCP_RX_SN in the state variable is greater than the sequence of the received PDU The value of RX_HFN will be increased by 1. Therefore, if there are still out-of-order data packets after returning to the normal data packet processing method, it may cause the RX_HFN at both ends to lose synchronization, and the receiving end cannot correctly decrypt the received data, thus The data transmission cannot be carried out smoothly

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