What is PDU and SDU?
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).
Which RLC entity can send a status PDU?
Triggering a STATUS report A STATUS PDU is sent to the peer RLC layer to acknowledge received RLC SDUs and RLC SDU segments.
What is RLC mode in LTE?
Radio link control (RLC) is a layer 2 Radio Link Protocol used in UMTS, LTE and 5G on the Air interface. The main tasks of the RLC protocol are: Transfer of upper layer Protocol Data Units (PDUs) in one of three modes: Acknowledged Mode (AM), Unacknowledged Mode (UM) and Transparent Mode (TM)
What is status PDU in LTE?
RLC ŚTATUS PDU is sent from the receiver to the transmitter in order to provide the status of the PDUs which are correctly received and which are lost during transmission. The transmitting side after receiving the STATUS PDU, removes the PDU which are correctly received at the receiver from the retransmission buffer.
What is RLC SDU?
An RLC PDU (Protocol Data Unit) consists of an RLC header and data. From an upper layer, RLC receives an RLC SDU (Service Data Unit). The data part of an RLC PDU is either a complete RLC SDU or an SDU segment. A single RLC PDU maps to a single MAC SDU . RLC has three transmission modes: TM , UM and AM .
What is N SDU?
In effect the SDU is the ‘payload’ of a given PDU. The layer (n) may add headers or trailers, or both, to the SDU and may do other kinds of reformatting, recoding, splitting or transformations on the data, forming one or more layer (n) PDUs.
What is T PollRetransmit?
Description. t-PollRetransmit. This timer is used by the transmitting side of an AM RLC entity in order to retransmit a poll.
What is RRC PDU?
An RRC PDU, which is the bit string that is exchanged between peer entities/across the radio interface contains the basic production as defined in X. – upon reception of an RLC SDU from the RLC layer, the first bit of the RLC SDU shall represent the first bit of the RRC PDU and onwards.
What is PDCP and RLC?
PDCP is the lowest throughput. Then RLC throughput is higher than PDCP throughput not only due to headers but also due to RLC retransmissions. Then MAC throughput is higher than RLC throughput due to harq retransmissions and headers. Then PHY throughput is higher due to headers.
What is RLC entity?
An RLC entity is established when a radio bearer is set up, and removed when the associated radio bearer is released. When established, the RLC entity is configured in one of three operating modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM).
What is RLC SAP?
RLC – Radio Link Control protocol is a data link layer protocol. RRC (Radio Resource Control) is generally controls RLC configuration via RRC-RLC SAP. A RLC entity receives/delivers RLC SDUs from/to upper layer and ends/receives RLC PDUs to/from its peer RLC entity via lower layers.
What is SDU 5G?
In the transmitter side, a layer N receives data from layer N+1 and this data is called the SDU or Service Data Unit. This layer will modify the data and convert it into a PDU or a Protocol Data Unit. The peer entity in the receiver is only able to understand this PDU.
What is the data part of a RLC PDU?
An RLC PDU (Protocol Data Unit) consists of an RLC header and data. From an upper layer, RLC receives an RLC SDU (Service Data Unit). The data part of an RLC PDU is either a complete RLC SDU or an SDU segment.
How are SDU’s converted to PDU in LTE?
The SDU’s are received from higher layer, which is from PDCP in case of LTE. These SDU’s have to be converted to PDU’s so they undergo segmentation and concatenation and suitable RLC headers are added to form the RLC PDU’s.
What does the so mean in RLC SDU?
Segment Offset (SO): Indicates the position of the current segment in bytes within the original RLC SDU. Numbering starts from zero. Length is 16 bits. Sequence Number (SN): Indicates the sequence number of the corresponding SDU.
Which is the upper layer of RLC bap or PDU?
RLC ‘s upper layer is either PDCP or BAP. If RLC SDU is from PDCP, the maximum data field size in an RLC PDU is the maximum size of a PDCP PDU. Unlike LTE RLC, 5G NR RLC supports SDU segmentation but not concatenation.