Access Point Deviation Calibration for Synchronized Transmission
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Solution Overview
Problem
Current Coordinated multi-point (Comp) technology in LTE-Advanced systems faces challenges with channel delay inequality and timing synchronization deviations among multiple access points, leading to reduced system performance and frequency spectrum efficiency, particularly when multiple access points transmit data simultaneously to a user equipment (UE).
Innovation Solution
A method where a base station instructs a user equipment (UE) to measure and return deviation calibration information, allowing the base station to calibrate channel delay inequality and phase differences among access points, thereby eliminating deviations and improving system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple access points transmit data simultaneously to improve system performance and frequency spectrum efficiency, then the edge user experience is improved, but channel delay inequality and timing synchronization deviations occur among access points
Solution Approach 1:
The patent implements a feedback mechanism where the user equipment measures the downlink channel from multiple access points, calculates timing synchronization deviation and phase calibration information, and feeds back these measurements to the base station. The base station then uses this feedback to adjust the transmission timing of different access points, creating a closed-loop system that continuously optimizes synchronization while maintaining high data transmission efficiency
Solution Approach 2:
The patent performs preliminary timing synchronization calibration by having the user equipment measure and report timing deviations before actual data transmission begins. The base station uses these preliminary measurements to pre-adjust the transmission timing of each access point, ensuring that when data transmission starts, the access points are already synchronized, thus preventing timing deviations from occurring during active transmission
2Device complexity
If each access point independently feeds back codebook information to reduce feedback complexity, then device complexity is reduced, but phase difference problems occur among access points
Solution Approach 1:
The patent introduces phase calibration information as an intermediary element that mediates between independent access point codebook feedback and coordinated transmission. The user equipment calculates phase calibration information based on measurements from multiple access points and feeds it back to the base station, which then uses this intermediary information to align the phases of different access points, enabling independent feedback mechanisms to work together coherently
Solution Approach 2:
The patent changes the feedback parameter from simple codebook information to include both codebook information and phase calibration information. This parameter enhancement allows each access point to maintain independent operation while providing the additional phase calibration data needed to correct phase differences, thus resolving the contradiction between independent feedback and phase synchronization
3Manufacturing precision
If phase calibration information is fed back with smaller granularity to overcome phase rotation deviation, then phase calibration accuracy is improved, but feedback expense increases
Solution Approach 1:
The patent applies partial action by having the user equipment measure and report phase calibration information only for the specific frequency domains where timing synchronization deviations occur, rather than across the entire frequency spectrum. This selective measurement approach provides sufficient phase calibration accuracy for affected areas while minimizing the amount of feedback data and associated energy consumption
Data Source
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AI summary
The embodiment of the present invention discloses a method, a system and an apparatus for calibrating deviation among multiple access points, which are used for solving a problem that information received by a user equipment (UE) is not synchronous, caused when different access points send data to the UE at the same time, and improving system performance and frequency spectrum efficiency. The method for calibrating deviation among multiple access points comprises the following steps: in step A: a base station sending to a UE a message instructing the UE to perform measurement and return deviation calibration information among the multiple access points (S101); and in step B: the base station calibrating the deviation among the multiple access points based on the deviation calibration information among the multiple access points returned by the UE (S102).