21 MU-MIMO operation in HSUPA channel in 1.28Mcps TDD

25.3193GPPEnhanced uplinkOverall descriptionStage 2TS

In 1.28Mcps TDD, MU-MIMO operation in HSUPA channel includes the following contents.

– Four midamble allocation patterns (pattern 1A, pattern 1B, pattern 2A, pattern 2B) for the special default midamble allocation scheme as in [13] shall be used for MU-MIMO operation. For the UEs sharing the same uplink physical resource in the same TTI, the different midamble allocation patterns shall be allocated to them.

– A MU-MIMO capable UE can be signalled to operate in "MU-MIMO mode" by RRC.

– MU-MIMO can be applied in CELL_DCH and CELL_FACH.

– If UE is configured in MU-MIMO mode and the default midamble allocation scheme is signalled to UE by RRC, the default or special default midamble allocation scheme can be used. Whether the default or special default midamble allocation scheme is used is signalled to UE dynamically through E-AGCH in [15].

– When UE is configured in MU-MIMO mode, the NodeB scheduler uses E-AGCH type 2 to signal the E-DCH related information to UE. When the special default midamble allocation scheme is signalled to UE through E-AGCH, the special default midamble pattern indicator on E-AGCH signals the UE’s midamble allocation pattern.

– When the special default midamble allocation scheme is signalled to UE through E-AGCH, the signature sequence allocated to UE to indicate the ACK/NACK for E-PUCH is related to both the E-DCH resources allocated by NodeB and the special default midamble pattern indicator signalled on E-AGCH.

– In CELL_DCH and CELL_FACH, the Node B scheduler decides whether to allocate the same uplink physical resource to multiple UEs in the same TTI based on the spatial isolation between the wireless channels of these UEs.

– In CELL_DCH, standalone midamble channel can be used to improve the uplink channel estimation, thus improving the wireless channel spatial isolaton decision performance.