A.5.2.1 MPAC Positioning Guidelines
37.5443GPPConformance testingRelease 16TSUniversal Terrestrial Radio Access (UTRA) and Evolved UTRA (E-UTRA)User Equipment (UE) Over The Air (OTA) performance
In order for the anechoic chamber multi probe system to emulate the intended propagation statistics within the region of space incident on the DUT antennas, two concepts determine the associated antenna spacing and positioning guidelines. The maximum antenna spacing in the DUT must be within the limit determined by the anechoic chamber multi probe system’s ability to emulate the spatial correlation function, and the power stability of the field incident on the DUT antennas must be verified.
a)
b)
Figure A.5.2.1-1: Illustration of DUT antenna spacing and positioning guidelines;
a) guideline in this specification, b) example with DUT meeting the maximum allowed antenna separation but not within the verified power stability region
As the channel model validation procedures for spatial correlation as defined in [29] are to be performed at the downlink centre frequency in 3GPP TS 36.508 [10], the maximum antenna spacing in the DUT shall be defined by the wavelength per operating band centre frequency of the middle channel of the downlink at the band under test. A verification of power stability can be derived from the spatial correlation verification results in [29]. Given that this verification spans a region with a diameter of 1 wavelength cantered on the axis of rotation in the chamber and that the performance demonstrated by multiple 8 dual-polarized probe MPAC implementations in [29] has shown good alignment up to 0.85 lambda for SCME UMi, the region where DUT antennas shall be placed (the MIMO OTA test zone) shall be defined in the same way (see Figure A.5.2.1-1a above) but further confined by the 0.85 lambda antenna separation limit for SCME UMi. Figure A.5.2.1-1b above provides an example of a DUT meeting the maximum allowed antenna separation but not within the verified power stability region; this placement of a DUT shall not be used. The optimization of the maximum allowed antenna spacing of the DUT and the verification of the test zone, as well as SCME UMa considerations, are expected as part of future work.
The region of uniform power delivered by the MIMO system (unverified) as shown in Figure A.5.2.1-1 is an indication of the region where the wave front may maintain its uniformity. Therefore, it may be used to extend the test volume but is not allowed at this time. It is considered unverified because the validation of spatial correlation provides a verification that spans a region of 1 lambda. Any further extension of the verified test volume would require an update to the spatial correlation validation in [29].
The DUT maximum antenna spacing and placement within the test zone shall be defined by the following two-tier methodology due to the primary radiation modes below 1 GHz and above 1 GHz and how they relate to the device and/or antenna size.
When operating in frequency bands lower than 1GHz, the physical centre of the DUT shall be placed in the chamber centre, the DUT shall be completely contained within the volume defined by the respective operating band equivalent to a sphere with a radius equal to 0.425 wavelengths as defined in Tables A.5.2.1-1 and Tables A.5.2.1-2 for SCME UMi.
When operating in frequency bands higher than 1 GHz the equidistant physical point between the DUT MIMO antenna system shall be placed in the chamber centre following guidance defined in Figure A.5.2.1-2 and the DUT MIMO antenna system (further physical dimension or both antennas’ maximum E-field regions) shall be completely contained within the volume defined by the respective operating band equivalent to a sphere with a radius equal to 0.425 wavelength defined in Tables A.5.2.1-1 and Tables A.5.2.1-2 for SCME UMi. The definition of the equidistant point between the DUT MIMO antennas shall be provided through manufacturer declaration for all operating bands where the maximum antenna separation requirement has been met. The location of the equidistant point(s) for each operating band shall be identified by the manufacturer by either marking the device utilized for MIMO OTA testing or by providing clear instructions to the test operator as to the physical location(s).
The two-tier approach is needed to be technically correct when defining the MPAC test volume. While the geometric centre can be used in frequencies lower than 1GHz, the same methodology will add unnecessary limitations for test applicability in frequencies above 1GHz. In this case, manufacturers will need to provide further information to enable the proper definition of the test volume. Ideally, the same approach adopted in frequencies above 1 GHz could be used for all frequencies. However, the extra positioning work and need to identify the equidistant point between the DUT MIMO antennas isn’t necessary for frequencies under 1GHz since the wavelength dimension is large enough for all handsets, phablets, and most tablets and laptops.
Figure A.5.2.1-2: Definition of distance between MIMO antennas and DUT centre, maximum physical separation, or E-field maximum separation defined by manufacturer
Table A.5.2.1-1: Test zone dimension definition vs. FDD band of operation
|
Band |
DL middle channel frequency (MHz) |
0.85*Wavelength (m) middle channel |
Test volume sphere radius (m) |
|
1 |
2140 |
0.119 |
0.060 |
|
2 |
1960 |
0.130 |
0.065 |
|
3 |
1842.5 |
0.138 |
0.069 |
|
4 |
2132.5 |
0.119 |
0.060 |
|
5 |
881.5 |
0.289 |
0.145 |
|
6 |
880 |
0.290 |
0.145 |
|
7 |
2655 |
0.096 |
0.048 |
|
8 |
942.5 |
0.270 |
0.135 |
|
9 |
1862.4 |
0.137 |
0.068 |
|
10 |
2140 |
0.119 |
0.060 |
|
11 |
1485.9 |
0.171 |
0.086 |
|
12 |
737.5 |
0.346 |
0.173 |
|
13 |
751 |
0.339 |
0.170 |
|
14 |
763 |
0.334 |
0.167 |
|
17 |
740 |
0.344 |
0.172 |
|
18 |
867.5 |
0.294 |
0.147 |
|
19 |
882.5 |
0.289 |
0.144 |
|
20 |
806 |
0.316 |
0.158 |
|
21 |
1503.4 |
0.169 |
0.085 |
|
22 |
3550 |
0.072 |
0.036 |
|
23 |
2190 |
0.116 |
0.058 |
|
24 |
1542 |
0.165 |
0.083 |
|
25 |
1962.5 |
0.130 |
0.065 |
|
26 |
876.5 |
0.291 |
0.145 |
|
27 |
860.5 |
0.296 |
0.148 |
|
28 |
780.5 |
0.326 |
0.163 |
|
29 |
722.5 |
0.353 |
0.176 |
|
30 |
2355 |
0.108 |
0.054 |
|
31 |
465 |
0.548 |
0.274 |
|
32 |
1474 |
0.173 |
0.086 |
Table A.5.2.1-2: Test zone dimension definition vs. TDD band of operation
|
Band |
DL middle channel frequency (MHz) |
0.85*Wavelength (m) middle channel |
Test Volume Sphere Radius (m) |
|
34 |
2017.5 |
0.126 |
0.063 |
|
35 |
1880 |
0.136 |
0.068 |
|
36 |
1960 |
0.130 |
0.065 |
|
37 |
1920 |
0.133 |
0.066 |
|
38 |
2595 |
0.098 |
0.049 |
|
39 |
1900 |
0.134 |
0.067 |
|
40 |
2350 |
0.108 |
0.054 |
|
41 |
2593 |
0.098 |
0.049 |
|
42 |
3500 |
0.073 |
0.036 |
|
43 |
3700 |
0.069 |
0.034 |
|
44 |
753 |
0.338 |
0.169 |
The positioning of the device under test within the test volume shall be set as defined above and in [29].
The environmental requirements for the device under test shall be set as defined in Annex M.