6 FR1 MIMO OTA requirements

38.1513GPPNRRelease 17TSUser Equipment (UE) Multiple Input Multiple Output (MIMO) Over-the-Air (OTA) performance requirements

6.1 General

6.1.1 Definition of MIMO throughput

The MIMO throughput is defined here as the time-averaged number of correctly received transport blocks in a communication system running an application, where a Transport Block is defined in the reference measurement channel. From OTA perspective, this is also called MIMO OTA throughput. It will be used as the baseline figure of merit for FR1 and FR2 MIMO OTA testing.

The MIMO OTA throughput is measured at the top of physical layer of NR system under the use of FRC, the SS transmit fixed-size payload bits to the DUT. The DUT signals back either ACK or NACK to the SS. The SS then records the following:

 Number of ACKs,

 Number of NACKs, and

 Number of DTX slots

Hence the MIMO (OTA) throughput can be calculated as

Where Transmitted TBS is the Transport Block Size transmitted by the SS, which is fixed for a FRC during the measurement period. MeasurementTime is the total composed of successful slots (ACK), unsuccessful slots (NACK) and DTX-symbols.

The time-averaging is to be taken over a time period sufficiently long to average out the variations due to the fading channel. Therefore, this is also called the average MIMO OTA throughput. The throughput should be measured at a time when eventual start-up transients in the system have evanesced.

6.1.2 Total Radiated Multi-antenna Sensitivity (TRMS)

The average TRMS of free space data mode portrait (FS DMP), free space data mode landscape (FSDML), and free space data mode screen up (FS DMSU), is defined as the FR1 MIMO OTA requirement. The averaging shall be done in linear scale for the TRMS results at these DUT positions, according to the formula:

where

Such that MODE is one of {FS_DMP, FS_DML, FS_DMSU}, and {PMODE,70,0, …, PMODE,70,11} are the measured sensitivity values at each azimuth position at the 70% throughput outage.

If 1 azimuth position does not result in a defined measured sensitivity at 70% throughput, SMODE,70 is calculated using the 11 measured sensitivities and the maximum downlink RS-EPRE PRS-EPRE-MAX (substitution approach) for the one missing result. PRS-EPRE-MAX is the maximum downlink RS-EPRE supported by the test system, and is defined as [-80dBm/15kHz (or equivalent 77dBm/30kHz)] for FR1 MIMO OTA.

The TRMS shall be measured at the mid channel as specified in TS 38.508-1 subclause 4.3.1 [7]. The average TRMS shall be lower than the average TRMS requirements specified in Clause 6.2.

The additional criterion in azimuthal orientations shall be met:

– The EUT must meet 70% throughput in 11 of total 12 azimuthal orientations. If the EUT fails to meet this criterion even under maximum downlink power condition (i.e. PRS-EPRE-MAX), the EUT shall fail the FR1 MIMO OTA test.

– The EUT must meet 90% throughput in [10] of total 12 azimuthal orientations. If the EUT fails to meet this criterion even under maximum downlink power condition (i.e. PRS-EPRE-MAX), the EUT shall fail the FR1 MIMO OTA test.

Note: whether define different criterion on 90%TP for bands ≥3GHz and Bands <3GHz is FFS.

6.2 Minimum requirement

<Editor’s note: Detailed structure of the subclause is TBD. Subclause for SA and EN-DC bands can be added>