PDCP
Encyclopedia
PDCP is an abbreviation for Packet Data Convergence Protocol. It is one of the layers of the Radio Traffic Stack in UMTS
and performs IP
header compression and decompression, transfer of user data and maintenance of sequence numbers for Radio Bearers which are configured for lossless
serving radio network subsystem (SRNS) relocation.
The compression technique can be based on either RFC 2507 or RFC 3095. RFC 1144 can also be used for some background information, and although the techniques in the RFC are not used in modern TCP/IP implementations, it still shows what the compression/decompression technique looks like.
If PDCP is configured for No Compression it will send the IP Packets without compression; otherwise it will compress the packets according to its configuration by upper layer and attach a PDCP header and send the packet. It uses the service provided by a lower layer called Radio Link Control (RLC) that uses the Radio Link Protocol
.
PDCP header consists of two fields: PID and PDU TYPE.
Universal Mobile Telecommunications System
Universal Mobile Telecommunications System is a third generation mobile cellular technology for networks based on the GSM standard. Developed by the 3GPP , UMTS is a component of the International Telecommunications Union IMT-2000 standard set and compares with the CDMA2000 standard set for...
and performs IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
header compression and decompression, transfer of user data and maintenance of sequence numbers for Radio Bearers which are configured for lossless
Lossless data compression
Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange...
serving radio network subsystem (SRNS) relocation.
The compression technique can be based on either RFC 2507 or RFC 3095. RFC 1144 can also be used for some background information, and although the techniques in the RFC are not used in modern TCP/IP implementations, it still shows what the compression/decompression technique looks like.
If PDCP is configured for No Compression it will send the IP Packets without compression; otherwise it will compress the packets according to its configuration by upper layer and attach a PDCP header and send the packet. It uses the service provided by a lower layer called Radio Link Control (RLC) that uses the Radio Link Protocol
Radio Link Protocol
Radio Link Protocol is an automatic repeat request fragmentation protocol used over a wireless air interface. Most wireless air interfaces are tuned to provide 1% packet loss, and most Vocoders are mutually tuned to sacrifice very little voice quality at 1% packet loss...
.
PDCP header consists of two fields: PID and PDU TYPE.
- PDU TypeProtocol data unitIn telecommunications, the term protocol data unit has the following meanings:#Information that is delivered as a unit among peer entities of a network and that may contain control information, address information, or data....
field indicates whether the PDU is Data PDU or Sequence Number PDU. - PID field value indicates header compression protocolBandwidth compressionIn telecommunication, the term bandwidth compression has the following meanings:*The reduction of the bandwidth needed to transmit a given amount of data in a given time.*The reduction of the time needed to transmit a given amount of data in a given bandwidth....
type used and packet type or CID.