13c MIMO mode with four transmit antennas modelling and operation in HSDPA channel in FDD (FDD only)

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

MIMO mode with four transmit antennas operation is characterized as simultaneous transmission of up to four streams to one UE in CELL_DCH. Certain categories of UE in CELL_DCH state may be configured with MIMO mode with four transmit antennas operation. A MIMO mode with four transmit antennas capable UE can be signalled by RRC.

When the UE is configured with MIMO mode with four transmit antennas operation:

– It should be possible to operate 64QAM on all streams simultaneously.

– If more than one HS-DSCH cell are configured, the TSN field in the MAC-ehs header use 14 contiguous bits. If one HS-DSCH cell is configured and "MIMO mode with four transmit antennas only with dual stream restriction" is not configured, the TSN field in the MAC-ehs header use 14 contiguous bits.

– Up to four HS-DSCH cells could be configured.

– For three stream transmission, the TB of the second stream and the TB of the third stream should be of equal size. For four stream transmission, the TB of the first stream and the TB of the fourth stream should be of equal size, and the TB of the second stream and the TB of the third stream should be of equal size.

– The UE sends the CQI, PCI and the number of TBs preferred information to the Node B, so that the Node B can select the number of streams and the MCSs. For the purpose of CQI, PCI and the number of TBs preferred evaluation, the UE assumes to get symmetric code allocation across streams.

– The Node B signals the number of scheduled streams and the used antenna weights through HS-SCCH, a precoding codebook with 64 matrices has been defined, the precoding will stay constant during one HS-PDSCH TTI with MIMO mode with four transmit antennas operation, the Node B scheduler decides on which precoding matrix to be used.

– The UE signals 1 out of 16 possible precoding matrices per stream.

– The DRX status is common for all streams. The DRX activation and deactivation is possible with HS-SCCH orders.

– When operating in MIMO mode with four transmit antennas, the use of DPCH as associated channel shall be supported, additionally the data rate on DPCH should be limited (e.g. to 64 kbps) when operating in MIMO mode with four transmit antennas.

– The mobility procedures, as defined in section 9, are supported based on the serving HS-DSCH cell. A serving cell change similar to the one shown in Figure 18-1 is possible for MIMO mode with four transmit antennas operation.

– HS-SCCH-less operation is restricted to the serving HS-DSCH cell.

– When operating in MIMO mode with four transmit antennas and using F-DPCH as associated channel, only single antenna transmission or STTD has to be supported on F-DPCH as defined in [6].

– The Node B transmits 4 common pilots all the time, and 2 demodulation common non-precoded pilots only when HS-PDSCHs are transmitted and demodulation common non-precoded pilots are activated, where the activation state of demodulation common non-precoded pilots is decided by the Node B and signalled to the UE by HS-SCCH orders.