Method and device for processing data during cell handover in lte system

Abstract

A method and UE for processing data during cell handover in a Long Term Evolution (LTE) system are provided. The method includes: receiving, by User Equipment (UE), a Sequence Number (SN) of a Packet Data Convergence Protocol-Service Data Unit (PDCP-SDU) that is received by a Source Evolved Node B (S_eNB) from a Target Evolved Node B (T_eNB); discarding, by the UE, the PDCP-SDU that is received by the S_eNB from a re-transmission queue, and re-transmitting other PDCP-SDUs in the queue to the T_eNB. Thereby, UE would not re-transmit PDCP-SDU corresponding to received SN, which avoids re-transmission of useless PDCP-SDU, and saves radio resources comparing with prior solutions.

1 . A method for processing data during cell handover in a Long Term Evolution (LTE) system, comprising:
 receiving, by User Equipment (UE), a Sequence Number (SN) of a Packet Data Convergence Protocol-Service Data Unit (PDCP-SDU) that is received by a Source Evolved Node B (S_eNB) from a Target Evolved Node B (T_eNB);   discarding, by the UE, the PDCP-SDU that is received by the S_eNB from a re-transmission queue, and re-transmitting other PDCP-SDUs in the queue to the T_eNB.   
     
     
         2 . The method according to  claim 1 , wherein the UE receives the SN of the PDCP-SDU that is received by the S_eNB through a synchronization reply message, a Radio Resource Control (RRC) message, a Radio Link Control (RLC) message or a Media Access Control (MAC) message. 
     
     
         3 . The method according to  claim 2 , further comprising:
 receiving, by the UE, a Handover Command message from the S_eNB; and   performing, by the UE, handover based on the Handover Command message.   
     
     
         4 . A User Equipment (UE) for processing data during cell handover in a Long Term Evolution (LTE) system, comprising: an Evolved Node B (eNB) interface unit and a queue adjustment unit, wherein
 the eNB interface unit is adapted to receive a Sequence Number (SN) of a Packet Data Convergence Protocol-Service Data Unit (PDCP-SDU) that is received by a Source Evolved Node B (S_eNB) from a Target Evolved Node B (T_eNB);   the queue adjustment unit is configured to discard the PDCP-SDU that is received by the S_eNB from a re-transmission queue;   the eNB interface unit is further configured to re-transmit other PDCP-SDUs in the queue to the T_eNB.   
     
     
         5 . The UE according to  claim 4 , further comprising: a re-transmission queue and a message parsing unit, wherein
 the re-transmission queue is adapted to buffer PDCP-SDUs; and   the message parsing unit is adapted to parse a message to obtain the SN of the PDCP-SDU that is received by the S_eNB.