The objectives for NR frequency range 2 (FR2) multi-Rx chain DL reception from RF perspective are as follows.

• Introduce necessary requirement(s) for enhanced FR2-1 UEs with simultaneous DL reception with two different QCL TypeD RSs on single component carrier with up to 4 layer DL MIMO:
  • Enhanced RF requirements:
    • Specify RF requirements, mainly spherical coverage requirements, for devices with simultaneous reception from different directions with different QCL TypeD RSs.
    • The legacy spherical coverage requirement for reception from a single direction will be kept.
    • PC3 will be prioritized, other power classes should be considered after the PC3 requirements framework is finalized.

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The existing Rel-15 NR FR2 minimum UE requirements are defined with an assumption that UE is equipped with a single antenna panel or two antenna panels but only capable to perform DL reception using a single RX beam/chain reception. Furthermore, the UE performance requirements are limited for DL MIMO rank 1 and 2. In FR2, 4-layer MIMO reception requires beam reception from at least two directions. Although this is supported by the MIMO features since Rel-15, no performance requirements have yet been specified. This is important for high-rate MIMO in FR2, as well as for FR2 HST scenarios. During Rel-16 and Rel-17, the support of NR FR2 CA with IBM (Independent Beam Management) with simultaneous DL reception on different component carriers from the co-located and non-col-located TRPs was defined. The IBM concept implies a UE is capable of DL simultaneous reception on different UE panels/chains using separate beams on different component carriers and requires improved UE baseband and RF capabilities (multiple baseband chains and support of multiple antenna panels). Several enhancements to enable efficient and robust DL multi-TRP/panel operation were introduced in the Rel-16 NR eMIMO WI. For instance, DL transmission schemes with simultaneous and non-simultaneous multi-beam reception from multiple TRPs/panels were introduced. The simultaneous reception may require support of simultaneous multi-panel operation with several independent RX beams/chains at the UE side. As part of this item, a new FR2 UE capability for simultaneous multi-beam reception was introduced (simultaneousReceptionDiffTypeD-r16). However, no RF, RRM or performance requirements were defined in Rel-16 and Rel-17 for FR2 UEs with simultaneousReceptionDiffTypeD-r16 capability. Enhanced NR FR2 UEs with multi-beam simultaneous reception and multiple RX chains can provide a meaningful performance improvement in FR2 improving both demodulation performance (4-layer DL MIMO), RRM performance and improve RF spherical coverage. This work item aims to introduce the requirements for UEs capable of multi-beam/chain simultaneous DL reception on a single component carrier to achieve improved RF, RRM and UE demodulation performance. Different implementation scenarios could be considered at the UE. Single-TCI reception on different beams has been supported by the RAN1 specifications since Rel-15 via the Type I codebook, which could be achieved at the UE with either a single panel or multiple panels. Alternatively, dual TCI operation can be combined with the Rel-17 mTRP framework even if the base station is actually deployed as a single TRP. This WI therefore provides the requirements for both single and dual TCI assumptions to specify requirements for reception of 4-layer downlink MIMO with simultaneous reception at the UE from two different directions.