Introduction

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The beamforming element antenna is specified as a standard equation based antenna plugin in SEAMCAT.

Figure: Beamforming element antenna parameters

The input parameters and the corresponding notation as used in the following equations are:

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The element antenna can be modified by selecting Edit next to Element antenna. The other input parameters and the corresponding notation as used in the following equations are as follows

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1. "use element antenna pattern": in this case no beamforming is applied outside of the system link's own channel. This is in line with the M.2101 specifications
2. "use composite antenna pattern": in this case beamforming is applied outside of the system link's own channel. This option provides additional flexibility to the user, recognising that in practice some degree of beamforming will occur in nearby channels (see section 10.6.4 below for additional options).

For example:

• If VLR uses Beamforming antenna and is selected "use element antenna pattern" then for Unwanted interference SEAMCAT will use composite antenna gain for VLR and for Blocking interference it will use element antenna gain for VLR (outside channel).
• If ILT uses Beamforming antenna and is selected "use element antenna pattern" then for Unwanted interference SEAMCAT will use element antenna gain for ILT (outside channel) and for Blocking interference it will use composite antenna gain for ILT.

 
The antenna peak gain is pre-calculated and shown for the input parameters (e.g. 23.1 dBi in Figure above). This is provided for validation purposes.

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• Pointing reference: towards the horizon
• Additional offset: Uniform distribution from -90° to +90°

Figure: Mobile station pointing settings

This is intended to reflect random user behaviour with the implementation of a UE with 2 antenna arrays pointing in opposite directions, where only the array which points towards the serving base station is active.

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Both of these options are illustrated below:

Figure: Beamforming antenna plot using "Gain envelope" mode

Figure: Beamforming antenna plot using "Full pattern" mode, with azimuth beamsteering angle set to 40 degrees

It is also possible to see the beamforming pattern on the individual event results – this can be useful to verify the gain values in a specific direction, as illustrated below:

Figure: Example of beamforming plots for interference between 2 IMT-2020 networks - ILT BS (red) to VLR UE (blue) - on the Event Results layout