Radio Head Calibration via Beamforming and Segmentation
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Solution Overview
Problem
In wireless communication systems with multiple radio heads, interference increases with the number of radio heads, and existing calibration methods, especially implicit approaches, become less accurate due to manufacturing drifts and external interference, leading to noisy channel estimates and reduced communication efficiency.
Innovation Solution
A method for calibrating radio heads using calibration signals transmitted and re-transmitted via beamforming, determining a calibration vector from received signals to adjust phase and amplitude, and applying a stitching coefficient for inter-radio head calibration, ensuring accurate channel reciprocity and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of radio heads is increased to provide simultaneous access to multiple client devices, then network capacity and client access capability are improved, but interference between radio heads increases and calibration accuracy deteriorates
Solution Approach 1:
The patent segments the calibration process into isolated calibration for individual radio heads and coordinated calibration for groups of radio heads. This segmentation allows each radio head to be calibrated independently first, avoiding interference from other radio heads during the calibration process, and then enables coordinated calibration to optimize overall system performance.
Solution Approach 2:
The patent introduces calibration signals as an intermediary mechanism to facilitate accurate calibration. These calibration signals are specifically designed to be transmitted during isolated calibration phases when no other radio heads are active, thereby eliminating interference and enabling precise channel estimation and calibration factor determination.
2Device complexity
If implicit calibration methods are used to reduce processing complexity, then device complexity is reduced, but calibration accuracy deteriorates due to manufacturing drifts and external interference
Solution Approach 1:
The patent performs preliminary isolated calibration of each radio head before coordinated calibration. During this preliminary phase, each radio head is calibrated independently without interference from other radio heads, establishing accurate baseline calibration factors that compensate for manufacturing drifts. This preliminary action ensures high calibration accuracy while maintaining reasonable processing complexity.
Solution Approach 2:
The patent implements periodic calibration updates where calibration signals are transmitted at specific intervals during isolated calibration phases. This periodic action allows the system to refresh calibration data regularly, compensating for manufacturing drifts and external interference while maintaining a balance between calibration accuracy and processing complexity.
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
Improves communication efficiency by accurately calibrating radio heads, reducing interference, and enhancing signal strength through beamforming, while providing cost savings in processing power compared to explicit calibration methods.
Implementation Method 1
re-transmitting the first calibration signal via beamforming of the plurality of antennas of the first radio head
Data Source
AI summary
Embodiments herein describe calibrating a plurality of radio heads having a plurality of wireless antennas. In one embodiment, the plurality of radio heads communicate a calibration signal in a round robin fashion such that each of the radio heads communicates a respective calibration signal to the remaining radio heads. In one embodiment, at least one of the radio heads is isolated from the remaining radio heads. The received calibration signals are then used to calibrate the radio heads. In one embodiment, a controller coupled with the plurality of radio heads calibrates the radio heads. The calibrated radio heads then communicate to one or more client devices.