Three-dimensional beamforming (3DBF), full dimension MIMO or tilt angle adaptation is an interference coordination method in cellular networks and radar systems which brings significant improvements in comparison with conventional 2D beamforming techniques. Most beamforming schemes currently employed in wireless cellular networks control the beam pattern radiation in the horizontal plane. In contrast to such two-dimensional beamforming (2DBF), 3DBF adapts the radiation beam pattern in both elevation and azimuth planes to provide more degrees of freedom in supporting users. By utilizing information on angle of arrival (AoA) of users provided by suitable antenna hardware such as

sector antenna A sector antenna is a type of directional microwave antenna with a sector-shaped radiation pattern. The word "sector" is used in the geometric sense; some portion of the circumference of a circle measured in degrees of arc. 60°, 90° and 120° ...

or planar array in both elevation and azimuth planes and estimating

direction of arrival In signal processing, direction of arrival (DOA) denotes the direction from which usually a propagating wave arrives at a point, where usually a set of sensors are located. These set of sensors forms what is called a sensor array. Often there is th ...

(DoA) of each users' signal, base station is capable of distinguishing different users using proper beamforming and also steering the array's beam to a desired direction which optimizes some preferred performance metric of the network.

Different types of 3DBF

Depending on the way that the antenna downtilt is changed, 3DBF can be classified into two categories: * Static 3DBF refers to a system where the antenna tilt at the BS is set to a fixed value according to some statistical metrics. * Dynamic 3DBF that steers the BS antenna tilting angle instantaneously according to specific user locations.

References

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