Massive MIMO Broadcast Beam Generation via Excitation Coefficient Optimization
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Solution Overview
Problem
Massive MIMO systems face challenges in generating broadcast beams that provide sector-like coverage while minimizing per-antenna transmit power imbalances, leading to inefficient power amplifier usage and increased costs due to large power amplifiers required for broadcast channels.
Innovation Solution
A method is developed to derive excitation coefficients for rectangular antenna arrays in massive MIMO systems, using entropic uncertainty principles to minimize the variation of per-antenna transmission powers, ensuring sector-like radiation patterns are achieved with optimized power distribution across antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a reduced number of antennas are reserved for broadcast beams, then sector-like coverage is achieved, but large power amplifiers are required leading to excessive cost, power consumption and heat dissipation
Solution Approach 1:
The invention segments the antenna array into multiple groups, where each group generates a specific broadcast beam. This segmentation allows the total transmit power to be distributed across multiple power amplifiers rather than concentrated in a few, thereby reducing the power consumption and heat dissipation of individual power amplifiers while maintaining comprehensive sector coverage.
Solution Approach 2:
The invention combines the functions of multiple antenna groups to collectively provide sector-like coverage. By merging the broadcast beams from multiple antenna groups, the system achieves comprehensive coverage without requiring any single power amplifier to operate at high power levels, thus reducing overall power consumption and heat dissipation.
2Loss of energy
If excitation coefficients are optimized to minimize per-antenna transmit power variations, then power amplifier efficiency is improved, but the complexity of calculating excitation coefficients increases
Solution Approach 1:
The invention changes the parameters of the excitation coefficients to minimize power variations across antennas. By optimizing these coefficients, the system balances the transmit power of individual antennas, improving power amplifier efficiency. The complexity is managed by formulating the optimization as a mathematical problem with constraints on power variation.
Solution Approach 2:
The system uses feedback mechanisms to adjust excitation coefficients based on observed power variations. By monitoring the transmit power of individual antennas and adjusting the excitation coefficients accordingly, the system minimizes power amplifier inefficiency while managing computational complexity through iterative optimization.
3Measurement precision
If multiple antennas are used to generate multiple data beams, then spatial resolution is improved, but per-antenna transmit power must be increased to maintain broadcast coverage
Solution Approach 1:
The invention segments the antenna array into multiple groups, with each group responsible for generating specific broadcast beams. This segmentation allows the system to maintain spatial resolution through multiple antenna groups while distributing the transmit power requirements across all groups, preventing any single antenna from requiring excessive power.
Solution Approach 2:
The invention combines the broadcast beam generation functions of multiple antenna groups to achieve both high spatial resolution and balanced power distribution. By merging the contributions of all antenna groups, the system maintains comprehensive broadcast coverage without requiring any individual antenna to operate at high power levels.
Data Source
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AI summary
A method and transmitter (10, 31) for generating broadcast beam patterns in massive MIMO systems, the transmitter (10, 31) comprising a rectangular antenna array (11,32) with a number N1 of antenna elements in the horizontal direction and a number N2 of antenna elements in the vertical direction. The MIMO transmitter (10, 31) generates broadcast beam patterns with determined beam widths in horizontal and vertical dimensions to cover a sector area (14) of a cell by the rectangular antenna array (11, 32) radiating N1xN2 radiofrequency signals (35) at a carrier frequency, the sector area (14) being where a user equipment (12, 34) requests from the MIMO transmitter (10, 31) access to the cell. The beam widths in horizontal and vertical directions are determined by using an optimum set of complex excitation coefficients calculated from a discretized continuous-space array factor ψ(θ, ϕ), which is based on a discretization over the elevation angle θ and the azimuth angle ϕ of the antenna elements.