Base Station Branch Calibration for CoMP MIMO
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Solution Overview
Problem
Existing methods for branch calibration in multiple base stations struggle to match uplink and downlink directivity during CoMP, making it difficult to achieve efficient communication, especially in scenarios requiring higher throughput like 6×N MIMO communication.
Innovation Solution
A base station system that adjusts individual calibration coefficients using a multiplying unit and storage unit to align the transfer functions of transmission and reception analog units across multiple branches, by sharing calibration coefficients through collaborative branch calibration with other base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If each base station individually performs branch calibration, then the transfer function ratio within each base station is regularized, but the transfer function ratios across multiple base stations cannot be regularized
Solution Approach 1:
The patent combines individual branch calibration with inter-base station calibration by having the communication terminal transmit calibration signals to multiple base stations simultaneously. Each base station measures the transfer function using its own calibration coefficients, then exchanges measurement results through a network management device to calculate adjustment coefficients that align transfer function ratios across all base stations, achieving unified regularization.
Solution Approach 2:
The system implements a feedback mechanism where each base station measures the transfer function using calibration signals from the terminal, reports measurements to the network management device, receives adjustment coefficients, and applies them to regularize the transfer function ratios across all base stations, creating a closed-loop calibration process.
2Ease of operation
If each base station individually performs branch calibration, then directivity is formed within each base station, but uplink directivity cannot be matched with downlink directivity across multiple base stations
Solution Approach 1:
The patent merges individual directivity formation with cross-base station directivity matching by having the terminal transmit uplink calibration signals that are received by multiple base stations. Each base station measures the transfer function and exchanges results through the network management device to calculate adjustment coefficients that ensure uplink directivity matches downlink directivity across all participating base stations.
Solution Approach 2:
The system uses feedback from uplink calibration signal measurements to adjust downlink transmission calibration coefficients. Each base station measures the transfer function using uplink calibration signals, reports to the network management device, receives adjustment coefficients, and applies them to align uplink and downlink directivity patterns across the CoMP network.
3Productivity
If individual branch calibration is performed, then 2×N MIMO communication is achieved per base station, but 6×N MIMO communication with higher throughput cannot be implemented
Solution Approach 1:
The patent combines individual base station calibration with inter-base station calibration to enable aggregate MIMO across multiple base stations. The terminal transmits calibration signals that are received by multiple base stations, which measure transfer functions and exchange results through the network management device to calculate adjustment coefficients, enabling coordinated 6×N MIMO communication that aggregates resources across base stations.
Data Source
AI summary
Provided is a base station including a plurality of branches that perform CoMP transmission with another base station, a multiplying unit that multiplies a transmission signal from each of the plurality of branches by a calibration coefficient of each of the plurality of branches, wherein the calibration coefficient is a coefficient obtained by adjusting an individual calibration coefficient acquired by branch calibration between the plurality of branches in the base station based on a branch calibration result between a branch of the base station and a branch of the other base station.