Open Loop Power Offset Update via Feedback
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Solution Overview
Problem
In wireless communication systems, open loop power control during the initial access phase often results in inaccurate transmit power estimation, leading to excessive interference or communication failures due to calibration errors and measurement errors, which prolongs the access time and can cause handoff issues.
Innovation Solution
A feedback mechanism is implemented to correct broadcast information, allowing mobile devices to report their measured power offset values to the base station, which updates the power offset estimates for subsequent access attempts, thereby improving the accuracy and speed of open loop power control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If open loop power control is used during initial access, then power estimation is performed, but measurement errors and calibration errors cause inaccurate transmit power estimation
Solution Approach 1:
The patent implements a feedback mechanism where mobile devices measure the received broadcast channel power, compare it with the indicated transmit power, calculate the power offset, and report it to the base station. The base station then updates the broadcast power indication based on these reported offsets. This closed-loop feedback process continuously refines the open-loop power control parameters, correcting measurement and calibration errors over time, thereby improving both measurement precision and communication reliability.
2Measurement precision
If power offset correction is implemented through feedback, then accuracy of power control improves, but system complexity increases
Solution Approach 1:
The feedback mechanism adds complexity but in a structured manner: mobile devices calculate power offsets based on simple measurements and comparisons, report them via existing signaling channels, and base stations update broadcast parameters. The complexity is distributed and incremental, using existing system resources rather than requiring completely new infrastructure.
Solution Approach 2:
Mobile devices autonomously measure power levels, calculate offsets, and generate correction reports without requiring complex centralized control. The system self-corrects by utilizing the collective measurements from multiple mobile devices to refine the broadcast power indications, reducing the need for external calibration procedures.
3Measurement precision
If mobile devices wait for accurate power control calibration, then power estimation accuracy improves, but access time increases
Solution Approach 1:
The base station pre-calculates and broadcasts power indication parameters before mobile devices need to transmit. Mobile devices use these pre-provided parameters for initial power estimation, allowing them to begin transmission immediately rather than waiting for iterative calibration. The feedback-based offset correction then refines this initial estimation in subsequent accesses.
Solution Approach 2:
Power offset information is accumulated and updated continuously through feedback from multiple mobile devices. This running correction refines the broadcast power indications over time, so that even the initial open-loop estimation becomes progressively more accurate without requiring each device to wait for individual calibration.
4Reliability
If higher transmit power is used to ensure communication during handoff, then communication reliability improves, but interference to neighboring devices increases
Solution Approach 1:
The feedback mechanism provides continuous refinement of power control parameters based on actual received power measurements. This allows the system to determine the minimum necessary transmit power for reliable communication during handoff, avoiding excessive power transmission that would cause interference to neighboring cells.
Solution Approach 2:
The system dynamically adjusts the power offset parameter based on feedback from mobile devices. By changing this parameter incrementally based on actual conditions rather than using fixed high power settings, the system achieves reliable handoff communication while minimizing interference to neighboring devices.
Data Source
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AI summary
Provided is a feedback mechanism to correct power control information in a broadcast signal that is determined to be incorrect by one or more devices that receive and rely on the broadcast information. A device that receives the incorrect broadcast information can determine a correction to the information and provide a recommendation to the source of the broadcast information. The source can selectively determine whether to modify the broadcast information based on the recommendation from one or more devices. If the broadcast information is modified, subsequent devices that receive the broadcast information are provided with the modified information. If further changes are needed, the subsequent devices can provide further recommended changes.