Beamforming Antenna Weight Control for Interference Suppression
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Solution Overview
Problem
Beam forming techniques in wireless communication systems can increase signal strength for intended user equipment (UEs) but also cause interference to UEs in neighboring cells, potentially nullifying the system-level gain due to increased interference.
Innovation Solution
A method is implemented in a network node to control communication between a radio base station (RBS) and UEs by obtaining information on expected propagation path direction intervals, defining communication power limits, and determining antenna weights to suppress power in interference directions while maintaining sufficient power in serving directions, thereby reducing interference and enhancing system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If beam forming is used to concentrate signal power towards serving UEs, then signal strength and SINR at receiving UEs are improved, but interference to UEs in neighboring cells increases
Solution Approach 1:
The patent applies local quality by creating direction-dependent beam forming characteristics where different spatial regions experience different signal and interference levels. By controlling antenna weights to create nulls in specific directions toward neighboring cells while maintaining beam formation toward serving cells, the system achieves locally optimized quality - strong signals for served UEs and suppressed interference in neighboring directions simultaneously
Solution Approach 2:
The patent converts the harmful effect of beam forming (interference to neighboring cells) into a beneficial outcome by using the same beam forming capability to create nulls in interference directions. The antenna weight control mechanism transforms what would be harmful concentrated energy into directed nulls that actively suppress interference, turning the beam forming effect against itself in a beneficial way
2Reliability
If beam forming is used to improve signal concentration, then SINR at receiving UE is improved, but system-level gain is lost due to increased interference in neighboring cells
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting antenna weight parameters based on spatial information about serving and neighboring cells. By changing the antenna weight parameters to create direction-specific beam patterns with nulls toward neighboring cells, the system maintains high SINR for served UEs while controlling overall interference levels, thus preserving system-level gain
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively mitigates interference to UEs served by other neighboring RBSs while ensuring sufficient signal strength for intended UEs, thereby improving overall system performance and maintaining the gain achieved through beam forming.
Implementation Method 1
The antennas are individually supplied with a weighted amount of the DL signal in such a way that the individual signals, when transmitted from the RBS, experience constructive interference between each other at a transmission angle towards a receiving UE while at other angles the individual signals experience destructive interference.
Data Source
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AI summary
The present invention relates to a network node and a method performed by the network node for controlling communication between a radio base station, RBS, and user equipments, UEs. The RBS has multiple antennas and uses beam forming when communicating with the UEs. The method comprises obtaining (702) information on an expected first propagation path direction interval between the RBS and UEs served by other neighboring RBSs, and obtaining (704) information on an expected second propagation path direction interval between the RBS and served UEs; defining (706) a first communication power limit for each of a plurality of beams according to the obtained information, the first limit being defined to suppress communication power in the first propagation path direction interval, when the plurality of beams are transmitted; and determining (708) antenna weights for each of the plurality of beams based on the defined first communication power limit.