Receiving UM-RLC entity: UE/UTRAN UTRAN/UE
• The receiving UM-RLC entity receives UMD PDUs through the configured logical channels from the lower layer.
• The receiving UM RLC entity deciphers (if ciphering is configured and started) the received UMD PDUs (except for the UMD PDU header). It removes RLC headers from received UMD PDUs, and reassembles RLC SDUs (if segmentation and/or concatenation has been performed by the transmitting UM RLC entity).
• RLC SDUs are delivered by the receiving UM RLC entity to the upper layers through
the UM-SAP.
Transmitting UM-RLC entity:
• The transmitting UM-RLC entity receives RLC SDUs from upper layers through the UM-SAP.
• The transmitting UM RLC entity segments the RLC SDU into UMD PDUs of appropriate size, if the RLC SDU is larger than the length of available space in the UMD PDU. The UMD PDU may contain segmented and/or concatenated RLC SDUs. UMD PDU may also contain padding to ensure that it is of a valid
length. Length Indicators are used to define boundaries between RLC SDUs within UMD PDUs. Length Indicators are also used to define whether Padding is included in the UMD PDU.
• If ciphering is configured and started, an UMD PDU is ciphered (except for the UMD PDU header) before it is submitted to the lower layer.
• The transmitting UM RLC entity submits UMD PDUs to the lower layer
through either a CCCH, SHCCH, DCCH, CTCH or a DTCH logical channel.
