17 HS-DSCH reception in CELL_PCH and URA_PCH states (1.28Mcps TDD only)

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

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The HS-DSCH reception in CELL_PCH and URA_PCH state is enabled by the UTRAN by including the parameters for HS-DSCH reception in CELL_PCH and URA_PCH state in the system information broadcast Parameters include PICH, HS-SCCH, and HS-DSCH configuration used for PCCH and DCCH/DTCH transmission in CELL_PCH and URA_PCH state. The HS-DSCH reception in CELL_PCH and URA_PCH state supports discontinuous reception as when DRX is used the UE needs only to monitor one Page Indicator, PI, in one Paging Occasion per DRX cycle.

In a multi-frequency cell, resources for HS-DSCH reception in CELL_PCH and URA_PCH including PICH, HS-SCCH and HS-DSCH configuration is only on primary frequency.

UTRAN obtains the knowledge of the UE supporting the reception of HS-DSCH in CELL_PCH and URA_PCH state from the RRC Connection Request/Complete message. The support of HS-DSCH reception in CELL_PCH and URA_PCH state is optional for UE.

When the HS-DSCH reception in CELL_PCH is enabled, the UTRAN can configure the UEs to store the E-RNTIs and dedicated H-RNTIs when performing reconfiguration to CELL_PCH.

For UE with stored H-RNTI, the network should use the stored dedicated H-RNTI to inform the UE to establish the uplink synchronization via HS-SCCH before transmitting DCCH and DTCH to the UE. When UE receives dedicated H-RNTI on HS-SCCH, the UE shall initiate the uplink synchronization procedure and transit to CELL_FACH state.

For UE without the E-RNTI and H-RNTI in CELL_PCH and URA_PCH, if PCH is configured in the cell, the PCCH is sent on the legacy PCH, otherwise UTRAN can send paging message on PCCH mapped on HS-DSCH.

The same paging block structure for PCH is used when PCCH is mapped on HS-DSCH, details in [8].

The BCCH is mapped on HS-DSCH for transmitting system information change information to the UEs with dedicated H-RINT in CELL_PCH 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. In a multi-frequency cell, the transmission of BCCH on HS-DSCH to the UE in CELL_PCH state is only on primary frequency.

The UE in CELL_PCH and URA_PCH states receiving HS-DSCH performs normal cell reselection process. The inter frequency and inter RAT cell reselection is supported as previous releases. When UE enters to a new cell, it obtains the valid HS-SCCH configuration from system information broadcast and performs Cell Update procedure.

The DCCH/DTCH over HSDPA reception in CELL_PCH state utilizes the enhanced L2 architecture with flexible RLC PDU size and MAC-ehs segmentation as defined in clause 6 and in [7].

17.1 UE operation

When HS-DSCH reception is configured in the system information broadcast, the UE shall after receiving a paging indication on PICH for its specific PI, start monitoring either a stored dedicated H-RNTI value on the HS-SCCH or if the UE does not have a dedicated H-RNTI value, it shall start monitoring the broadcasted HS-PDSCH code using indicated transport block sizes used for PCCH transmissions.

In a multi-frequency cell, UEs in URA_PCH or CELL_PCH stay on primary frequency.

The UE shall monitor either the HS-SCCH or the HS-PDSCH after time offset N_GAP defined between PICH and HS-SCCH or the HS-PDSCH.

When the UE in URA_PCH or CELL_PCH without dedicated H-RNTI detects the PICH identifying PCCH transmission, the UE shall receive the corresponding HS-DSCH TTIs:

– considering that paging message is retransmitted in 2*m subframes, the parameter m is the number of frame that each paging sub-channel occupies.

– combine retransmissions to same HARQ buffer;

– if the CRC is correct the UE shall pass the data to MAC-ehs;

– if the CRC fails after receiving 2*m subframes the UE resumes the DRX operation.

NOTE: When the UE receives the HS-PDSCH due to reception of PCCH, the UE is not required to receive any HS-SCCH.

When the UE in CELL_PCH with dedicated H-RNTI detects the PICH identifying DCCH/DTCH transmission, the UE shall receive the corresponding HS-SCCH subframes:

– if the UE detects the dedicated H-RNTI on the HS-SCCH, the UE shall initiate the uplink synchronization procedure and transit to CELL_FACH state;

– if UE does not detect the dedicated on H-RNTI on HS-SCCH in any of the n subframes the UE resumes the DRX operation, n is configured by higher layer.

The UE in CELL_PCH with dedicated H-RNTI shall also detect BCCH specific H-RNTI when it detects the PICH identifying DCCH/DTCH transmission:

– if the UE detects the BCCH specific H-RNTI on the HS-SCCH in any of the n subframes, the UE shall receive the corresponding HS-DSCH TTI.

For uplink transmission the UE shall use the E-DCH. The UE shall perform the state transition to CELL_FACH state when initiate the uplink transmission. After initiating the uplink transmission, the UE shall remain in CELL_ FACH state, unless a state change is triggered by RRC signalling.

During the state transition from CELL_PCH to CELL_DCH, if the reconfiguration message on DCCH does not include new H-RNTI the UE keeps monitoring the HS-SCCH with the dedicated H-RNTI value used in CELL_PCH or URA_PCH state during the uplink synchronisation procedure. The UE shall continue to use the dedicated H-RNTI in CELL_DCH state after completing the state.