Content for  TS 38.322  Word version:  18.1.0

In the definition of each field in clauses 6.2.3.2 to 6.2.3.5, the bits in the parameters are represented in which the first and most significant bit is the left most bit and the last and least significant bit is the rightmost bit. Unless mentioned otherwise, integers are encoded in standard binary encoding for unsigned integers.

Data field elements are mapped to the Data field in the order which they arrive to the RLC entity at the transmitter. For TMD PDU, UMD PDU and AMD PDU:

• The granularity of the Data field size is one byte;
• The maximum Data field size is the maximum size of a PDCP PDU.

For TMD PDU:

• Only one RLC SDU can be mapped to the Data field of one TMD PDU.

For UMD PDU, and AMD PDU:

• Either of the following can be mapped to the Data field of one UMD PDU, or AMD PDU:
  • One RLC SDU;
  • One RLC SDU segment.

Length: The SN field indicates the sequence number of the corresponding RLC SDU. For RLC AM, the sequence number is incremented by one for every RLC SDU. For RLC UM, the sequence number is incremented by one for every segmented RLC SDU.

Length: The SI field indicates whether an RLC PDU contains a complete RLC SDU or the first, middle, last segment of an RLC SDU.

Length: The SO field indicates the position of the RLC SDU segment in bytes within the original RLC SDU. Specifically, the SO field indicates the position within the original RLC SDU to which the first byte of the RLC SDU segment in the Data field corresponds. The first byte of the original RLC SDU is referred by the SO field value "0000000000000000", i.e., numbering starts at zero.

Length: The D/C field indicates whether the RLC PDU is an RLC data PDU or RLC control PDU. The interpretation of the D/C field is provided in Table 6.2.3.6-1.

Length: The P field indicates whether or not the transmitting side of an AM RLC entity requests a STATUS report from its peer AM RLC entity. The interpretation of the P field is provided in Table 6.2.3.7-1.

Length: The R field is a reserved field for this release of the protocol. The transmitting entity shall set the R field to "0". The receiving entity shall ignore this field.

Length: The CPT field indicates the type of the RLC control PDU. The interpretation of the CPT field is provided in Table 6.2.3.9-1.

Length: The ACK_SN field indicates the SN of the next not received RLC SDU which is not reported as missing in the STATUS PDU. When the transmitting side of an AM RLC entity receives a STATUS PDU, it interprets that all RLC SDUs up to but not including the RLC SDU with SN = ACK_SN have been received by its peer AM RLC entity, excluding those RLC SDUs indicated in the STATUS PDU with NACK_SN, portions of RLC SDUs indicated in the STATUS PDU with NACK_SN, SOstart and SOend, RLC SDUs indicated in the STATUS PDU with NACK_SN and NACK_range, and portions of RLC SDUs indicated in the STATUS PDU with NACK_SN, NACK range, SOstart and SOend.

Length: The E1 field indicates whether or not a set of NACK_SN, E1, E2 and E3 follows. The interpretation of the E1 field is provided in Table 6.2.3.11-1.

Length: The NACK_SN field indicates the SN of the RLC SDU (or RLC SDU segment) that has been detected as lost at the receiving side of the AM RLC entity.

Length: The E2 field indicates whether or not a set of SOstart and SOend follows. The interpretation of the E2 field is provided in Table 6.2.3.13-1.

Length: The SOstart field (together with the SOend field) indicates the portion of the RLC SDU with SN = NACK_SN (the NACK_SN for which the SOstart is related to) that has been detected as lost at the receiving side of the AM RLC entity. Specifically, the SOstart field indicates the position of the first byte of the portion of the RLC SDU in bytes within the original RLC SDU. The first byte of the original RLC SDU is referred by the SOstart field value "0000000000000000", i.e., numbering starts at zero.

Length: When E3 is 0, the SOend field (together with the SOstart field) indicates the portion of the RLC SDU with SN = NACK_SN (the NACK_SN for which the SOend is related to) that has been detected as lost at the receiving side of the AM RLC entity. Specifically, the SOend field indicates the position of the last byte of the portion of the RLC SDU in bytes within the original RLC SDU. The first byte of the original RLC SDU is referred by the SOend field value "0000000000000000", i.e., numbering starts at zero. The special SOend value "1111111111111111" is used to indicate that the missing portion of the RLC SDU includes all bytes to the last byte of the RLC SDU. When E3 is 1, the SOend field indicates the portion of the RLC SDU with SN = NACK_SN + NACK range - 1 that has been detected as lost at the receiving side of the AM RLC entity. Specifically, the SOend field indicates the position of the last byte of the portion of the RLC SDU in bytes within the original RLC SDU. The first byte of the original RLC SDU is referred by the SOend field value "0000000000000000", i.e., numbering starts at zero. The special SOend value "1111111111111111" is used to indicate that the missing portion of the RLC SDU includes all bytes to the last byte of the RLC SDU.

Length: The E3 field indicates whether or not information about a continous sequence of RLC SDUs that have not been received follows.

Length: This NACK range field is the number of consecutively lost RLC SDUs starting from and including NACK_SN.