Method for processing radio protocol in mobile telecommunications system and transmitter of mobile telecommunications
An apparatus and method for performing procedures (protocols) of a PDCP (Packet Data Convergence Protocol) layer and an RLC (Radio layer in an E-UMTS (Evolved Universal Mobile Telecommunications System) which has evolved from UMTS, among radio protocols of a mobile communication system. The PDCP layer performs ciphering on data (i.e., PDCP SDU) received from an upper layer, generates an indicator discriminating ciphered data and non-ciphered data (i.e., an ROHC feedback packet directly generated by the PDCP layer), and transmits the same to a lower layer (i.e., MAC layer). A PDCP SN (Sequence Number) is defined as an algorithm for ciphering the data in the PDCP layer to perform ciphering in the PDCP layer.
1. A mobile communication transmitter comprising:
a first SN (Sequence Number) setting module configured to receive data from an upper layer and set a first PDCP (Packet Data Convergence Protocol) SN associated with the data;
a header compression module configured to compress a header of the received data;
a ciphering module configured to cipher the header-compressed data;
a second SN setting module configured to add a second PDCP SN to the ciphered data and transfer the second PDCP SN-added data to a lower layer,
a segmentation and concatenation module configured to segment or concatenate the second PDCP SN-added data; and
a third SN setting module configured to add a third SN to the segmented or concatenated data,
wherein the second PDCP SN is the first PDCP SN which was previously set, and
wherein the data received by the first SN setting module from the upper layer is a PDCP SDU (Service Data Unit), and the second PDCP SN-added data transferred by the second SN setting module to the lower layer is a PDCP PDU (Protocol Data Unit).
2. The transmitter of claim 1 , wherein the ciphering module or the second SN setting module adds an indicator indicating whether the second PDCP SN-added data has been ciphered.
3. The transmitter of claim 2 , wherein the indicator is added in front of an SN field in the second PDCP SN-added data.
4. The transmitter of claim 1 , wherein the header compression module generates data independently from the data received from the upper layer.
5. The transmitter of claim 4 , wherein the data generated by the header compression module is not ciphered by the ciphering module.
6. The transmitter of claim 5 , wherein the data generated by the header compression module is feedback data unrelated to the data received from the upper layer.
7. The transmitter of claim 6 , wherein the data generated by the header compression module is an ROHC (Robust Header Compression) feedback packet.
8. The transmitter of claim 1 , further comprising:
a first buffer configured to store the data received from the upper layer.
9. The transmitter of claim 8 , further comprising:
a second buffer configured to receive and store the second PDCP SN-added data; and
a third buffer that stores the third SN-added data.
10. The transmitter of claim 9 , wherein the second buffer is an RLC (Radio Link Control) SDU buffer, and the third buffer is an RLC PDU buffer.
11. The transmitter of claim 9 , wherein the third SN added by the third SN setting module is an RLC SN.
12. The transmitter of claim 8 , wherein the first buffer is a PDCP SDU buffer, and the lower layer is an RLC layer.
13. The transmitter of claim 1 , wherein the lower layer is an RLC layer operating in an AM (Acknowledged Mode).