Method and apparatus for sending packet, updating and maintaining hyper frame number, and processing data

An apparatus for processing data on Packet Data Convergence Protocol (PDCP) layer, comprising:

• a processor and a memory;
• wherein the processor is configured to determine, based on a sequence number in a received packet, whether to read a service data unit in the received packet;
• and configured to determine, when the service data unit in the received packet does not need to be read, whether a header compression algorithm is configured for a PDCP entity of the apparatus or for a bearer link corresponding to the PDCP entity;
• and configured to discard the service data unit in the received packet when no header compression algorithm is configured for the PDCP entity or for the bearer link corresponding to the PDCP entity.

An apparatus for maintaining a Packet Data Convergence Protocol (PDCP) layer hyper frame number state, comprising:

• a processor and a memory;
• wherein the processor is configured to update a hyper frame number state based on a sequence number in a received packet;
• and configured to determine, when a packet error occurs subsequently, determine whether the hyper frame number has been modified;
• and
• configured to recover the hyper frame number to a before-modification state when the hyper frame number has been modified.