What is PDCP layer in LTE?
What is PDCP layer in LTE?
PDCP is located in the Radio Protocol Stack in the UMTS/LTE/5G air interface on top of the RLC layer. PDCP provides its services to the RRC and user plane upper layers, e.g. IP at the UE or to the relay at the base station.
What is PDCP SN?
It means U-Plane data, DTCH data is using this kind of data structure. The only differences between these two data type is the size of SN (Sequence Number). One is using 7 bit and the other is 12 bits. Comparing to SRB PDCP structure, you would find two differences. D/C bit at the first bit of the structure.
What is header compression in PDCP?
Abstract: Header compression is the process of reducing protocol header overhead in order to improve link efficiency while maintaining the end-to-end transparency. Robust header compression (ROHC) is a scheme for IMS (IP multimedia subsystem) and MBMS (multimedia broadcast multicast service).
What is the function of PDCP in LTE?
From UMTS, the main function of the PDCP layer has been the header compression of IP packets – this is the reason why it is called the Packet Data Convergence Protocol. In LTE, the PDCP layer has evolved to support a security function; that is, integrity protection and ciphering.
What is HFN PDCP?
HFN is a timer at the next level to SFN. HFN ranges between 0 and 1023 and the value increases by 1 when SFN reaches 1023 and reset to 0.
What is PDCP SDU?
A PDCP SDU is a bit string and is aligned by bytes, that is, a multiple of 8 bits, in length. From the first bit of the PDCP Data PDU, a compressed or uncompressed SDU is included. The below figure represents PDCP Data PDU format with 12 bits PDCP SN. This format fits for SRBs.
What is PDCP throughput?
DL: Throughput of PDCP SDU bits in downlink for packet sizes or data bursts that are large enough to require transmissions to be split across several TTIs, by excluding transmission of the last piece of data in a data burst.
What is the difference between PDU and SDU?
Protocol data units (PDUs) — packets exchanged between peer entities in the same layer. Service data units (SDUs) — packets handed to a lower layer by an upper layer. A PDU is typically a SDU with an additional header or trailer that carries information needed by that layer’s protocol.
What is PDCP discard timer?
the PDCP discard time is configured based on QoS requirement associated with a service. If the discard timer expires, it means the packet can no longer meet the QoS requirement.
What is difference between SDU and PDU?
Packets received by a layer are called Service Data Unit (SDU) while the packet output of a layer is referred to by Protocol Data Unit (PDU).
Can PDU vs SDU?
Why do I need 5G SDAP?
SDAP is responsible for QoS Flow handling across the 5G air interface. In particular, SDAP will map a specific QoS Flow within a PDU Session to a corresponding Data Radio Bearer (which has been established with the appropriate level of QoS).