Tapered Antenna Array Compensation for Transmitter Distortions
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Solution Overview
Problem
Tapered antenna arrays in beamforming base stations require increased peak output power capabilities to maintain equivalent isotropic radiated power and over-the-air error vector magnitude, leading to higher costs and power consumption, while existing distortion compensation methods either increase complexity or reduce achievable downlink data rates.
Innovation Solution
Split the antenna array into disjoint subsets of distorting and compensating antennas, using antennas with power headroom to transmit compensation signals for distortions, maintaining peak power capabilities comparable to non-tapered arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tapered antenna array is used to reduce sidelobes, then equivalent isotropic radiated power and over-the-air error vector magnitude are maintained, but peak output power requirements increase
Solution Approach 1:
The patent divides the antenna array into two disjoint subsets: distorting antennas (first subset) that operate without power headroom and compensating antennas (second subset) that operate with power headroom. This segmentation allows the system to use antennas with available power headroom to generate compensation signals that counteract distortions from antennas operating at peak power, thereby maintaining equivalent isotropic radiated power without increasing peak power requirements across the entire array.
Solution Approach 2:
The patent introduces compensation signals as an intermediary mechanism. These compensation signals are calculated based on estimated distortions from the distorting antennas and are combined with wanted signals at the compensating antennas. The compensation signals act as a mediator that counteracts the harmful distortion effects, allowing the system to maintain signal quality and equivalent isotropic radiated power without requiring all antennas to operate at high peak power levels.
2Manufacturing precision
If distortion compensation techniques are applied, then over-the-air error vector magnitude is maintained, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing antennas into distorting and compensating subsets, which simplifies the distortion compensation process. Instead of computing compensation for all antennas, the system only calculates compensation signals for the distorting subset and transmits them through the compensating subset. This segmented approach reduces computational complexity while maintaining over-the-air error vector magnitude performance.
Solution Approach 2:
The patent implements partial compensation by focusing distortion compensation efforts only on the distorting antenna subset rather than all antennas. The compensation signals are calculated and combined only for the necessary subset of antennas, achieving adequate distortion compensation and maintaining error vector magnitude performance with reduced computational overhead compared to full-array compensation approaches.
3Ease of manufacture
If antennas operate without power headroom, then cost is reduced, but signal distortions increase
Solution Approach 1:
The patent uses compensation signals as an intermediary to counteract the signal distortions generated by antennas operating without power headroom. The compensation signals are calculated based on estimated distortions from the distorting antennas and are combined with wanted signals at compensating antennas, effectively neutralizing the harmful distortion effects while allowing the distorting antennas to operate at lower cost configurations.
Solution Approach 2:
The patent converts the harmful signal distortions generated by low-cost antennas operating without power headroom into a manageable problem by calculating compensation signals that specifically target and counteract these distortions. The distortion characteristics of the distorting antennas are used to generate compensating signals that, when combined at the compensating antennas, eliminate the harmful effects and restore signal quality.
Data Source
AI summary
Example embodiments provide a method for compensating transmitter distortions. The compensation can be performed with tapered antenna elements. The method comprises determining a first subset of antennas of an antenna array, wherein the first subset of antennas operate without a power headroom in relation to one or more thresholds; determining a second subset of antennas of the antenna array, wherein the second subset of antennas comprise one or more antennas that operate with a power headroom in relation to the one or more thresholds; calculating compensation signals for distortions of wanted signals to be transmitted with the first subset of 10 antennas to one or more user devices; combining the compensation signals with wanted signals to be transmitted with the second subset of antennas to the one or more user devices; and transmitting, with the second subset of antennas, the compensation signals combined with the wanted signals. An apparatus, a method, and a computer program are disclosed.