What is hfn in pdcp?

To support this kind of new requirement, LTE has introduced another timer(clock) called HFN (Hyper Frame Number or Hyper SFN). 3GPP LTE Packet Data Convergence Protocol (PDCP) Sub Layer. Just "adding the PDCP header to the incoming data and forward to RLC in downlink", or "removing the PDCP header from the incoming packet and forward it to IP. How to prevent HFN desynchronization problem is left up to UE implementation. In sum, HFN de-synchronization occurs when the incorrect COUNT is used to decipher the received packet(s) leading to an incorrect result in the. A method and/or device that determines when an erroneous voice packet has been received over the air interface of a cellular communication.