LTE Unacknowledged Mode (UM) RLC PDU overview is discussed in another tutorial. If you want to learn the basics of UM data PDUs you can check the following tutorial.
In this tutorial examples for most important encoding techniques used for UM RLC PDUs are discussed.
UMD PDU with 5 bit SN (No LI)
Assumptions
Sequence Number (SN) Length: 5 bits
Sequence Number: 1
Service Data Unit (SDU): 01 02 03 04 05
Framing Info: 00
00: First byte of the data field corresponds to first byte of a RLC SDU & last byte of the Data field corresponds to last byte of a RLC SDU.
No Length Indicator is used.
UMD PDU with 10 bit SN (No LI)
Assumptions
Sequence Number (SN) Length: 10 bits
Sequence Number: 1
Service Data Unit (SDU): 01 02 03 04 05
Framing Info: 00
00: First byte of the data field corresponds to first byte of a RLC SDU & last byte of the Data field corresponds to last byte of a RLC SDU.
No Length Indicator is used.
UMD PDU with 5 bit SN (Odd number of LIs)
Sequence Number (SN) Length: 5 bits
Sequence Number: 1
SDU-1: 01 02 03
SDU-2: 04 05
SDU-3: 06 07 08
Framing Info: 00
00: First byte of the data field corresponds to first byte of a RLC SDU & last byte of the Data field corresponds to last byte of a RLC SDU.
SDUs are hex data.
UMD PDU with 5 bit SN (Even number of LIs)
Sequence Number (SN) Length: 5 bits
Sequence Number: 1
SDU-1: 01 02 03
SDU-2: 04 05
Framing Info: 00
00: First byte of the data field corresponds to first byte of a RLC SDU & last byte of the Data field corresponds to last byte of a RLC SDU.
SDU are hex data.
UMD PDU with 10 bit SN (Odd number of LIs)
Sequence Number (SN) Length: 10 bits
Sequence Number: 1
SDU-1: 01 02 03
SDU-2: 04 05
SDU-3: 06 07 08
Framing Info: 00
00: First byte of the data field corresponds to first byte of a RLC SDU & last byte of the Data field corresponds to last byte of a RLC SDU.
SDU are hex data.
UMD PDU with 10 bit SN (Even number of LIs)
Sequence Number (SN) Length: 10 bits
Sequence Number: 1
SDU-1: 01 02 03
SDU-2: 04 05
Framing Info: 00
00: First byte of the data field corresponds to first byte of a RLC SDU & last byte of the Data field corresponds to last byte of a RLC SDU.
SDU are hex data.
Further Studies
- LTE Radio Link Control (RLC) protocol specification – Release 8
- LTE for UMTS: Evolution to LTE-Advanced
- LTE Signaling: Troubleshooting and Optimization
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Hi Can you please explain more , it seems example easy but its not so clear for basic guys .
Good post but not clear .
Thanks for understanding
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Hi,
I am a bit confused of one part of the pictures for 10 bit UMD. In both picture for “E” of extension of LI1 seems to be 1 as it follows another set of “E” and “LI”, then why it is “0” (zero)?