14 HS-DSCH reception in CELL_FACH state (FDD only)

25.3083GPPHigh Speed Downlink Packet Access (HSDPA)Overall descriptionRelease 17Stage 2TS

The HS-DSCH reception in CELL_FACH state is enabled by the UTRAN by including the parameters for HS-DSCH reception in CELL_FACH state in the system information broadcast. Parameters include HS-SCCH, HS-DSCH configuration and common H-RNTI. UTRAN may also reconfigure HS-DSCH reception parameters (H-RNTI) by dedicated RRC signalling.

When HS-DSCH reception is configured in the cell, it shall take precedence instead of reception of S-CCPCH and FACH in CELL_FACH state.

The HS-DSCH is used to enable the reception of BCCH, CCCH, DCCH and DTCH logical channel data.

The BCCH is mapped on HS-DSCH for transmitting system information change information to the UEs in CELL_FACH state receiving HS-DSCH. The transmission of BCCH on HS-DSCH is performed by using BCCH specific H-RNTI on specific HS-SCCH code indicated in system information broadcast.

Simultaneous reception of HS-DSCH and S-CCPCH is only required in case of reception of MBMS ptm transmission.

The UE in CELL_FACH state receiving HS-DSCH performs normal cell reselection process except during periods when it is transmitting on common E-DCH resource, during which the UE is prevented from making cell reselections. The inter frequency and inter RAT cell reselection is supported by HS-DSCH measurement occasions as defined in subclause 14.3. When UE enters to a new cell, it obtains the valid HS-SCCH configuration from system information broadcast and performs Cell Update procedure.

UTRAN obtains the knowledge of the UE supporting the enhanced CELL_FACH state from the RRC Connection Request / Setup Complete messages and the Cell / URA update messages.

The HS-DSCH reception in CELL_FACH state utilizes the enhanced L2 architecture with flexible RLC PDU size and MAC-ehs segmentation as defined in clause 6 and in [7].