Uplink Power Control During Wireless Handover
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Solution Overview
Problem
In GSM/GPRS/EDGE wireless communication systems, there is a lack of effective methods to calculate uplink output power, especially during cell re-selection and frequency changes, leading to inefficient power usage and potential interference.
Innovation Solution
A method to calculate uplink output power by measuring the power of the downlink transmission channel in the target cell after a handover, without considering previous measurements from the current serving cell, using running average filters and specific equations to determine the normalized C value for determining the uplink output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If previous measured powers from the current serving cell are considered when calculating uplink output power in a target cell, then power calculation continuity is maintained, but measurement accuracy and adaptability to the new cell environment deteriorate
Solution Approach 1:
The patent segments the power calculation process by introducing a handover detection mechanism that divides the calculation into distinct phases: before handover (using previous measurements) and after handover (using only current cell measurements). This segmentation allows the system to maintain stability during normal operation while ensuring measurement accuracy during cell transitions.
Solution Approach 2:
The patent implements dynamic adjustment of the measurement window based on handover detection. The system dynamically switches between using previous measurements (for stability) and current measurements only (for accuracy) based on the handover state, making the measurement approach adaptive to the current operational context.
2Reliability
If the measurement window is not adjusted during handover, then measurement process simplicity is maintained, but measurement accuracy and reliability during cell transition deteriorate
Solution Approach 1:
The patent applies preliminary action by detecting handover events before they complete and proactively adjusting the measurement window accordingly. The system prepares for the transition by switching to current-cell-only measurements in advance, ensuring reliability during the critical handover period without requiring complex real-time adjustments.
3Productivity
If uplink output power is not optimized during handover, then system complexity is reduced, but power utilization efficiency and interference control deteriorate
Solution Approach 1:
The patent implements feedback mechanisms where the measured downlink power from the target cell is fed back into the uplink power calculation algorithm. This feedback loop allows the system to optimize uplink power based on actual received signal strength, improving power utilization efficiency while maintaining manageable complexity through the use of standard power control equations.
Data Source
AI summary
A method of calculating uplink output power in a wireless communication system is disclosed. More specifically, the method includes receiving a message which includes a command to a mobile station (MS) to perform handover from a current serving cell to a target cell, which is one of neighbor cells, performing handover to the target cell according to the message, measuring power of a downlink transmission channel in the target cell, and calculating the uplink output power by using only the measured power and without considering previous measured powers from the current serving cell if the measured power is used for a first calculation to obtain the uplink output power after the MS moves to the target cell.