Adaptive CDMA Power Control for Weak Signal Quality
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Solution Overview
Problem
In CDMA systems, communication quality and system capacity often conflict, with conventional power and handoff parameters being fixed, leading to unsatisfactory communication quality in areas with weak CDMA signals and high call-drop rates.
Innovation Solution
A Base Station Controller (BSC) stores multiple groups of quality control parameters and dynamically selects and transmits the appropriate parameters based on signal strength and workload to adjust power control and handoff parameters for each mobile station, improving communication quality in areas with weak CDMA signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the maximum transmit power threshold of the forward channel is increased to improve communication quality, then communication quality improves, but interference to other users increases and system capacity decreases
Solution Approach 1:
The patent applies dynamics by making the power control parameters adaptive rather than fixed. The Base Station Controller dynamically adjusts the maximum transmit power threshold based on real-time communication quality parameters (such as frame error rate and signal strength) reported by mobile stations. This allows the system to increase power thresholds when communication quality deteriorates and decrease them when quality is acceptable, thereby resolving the contradiction between communication quality and system capacity.
Solution Approach 2:
The patent changes the parameter values of power control thresholds based on communication conditions. By monitoring communication quality parameters and adjusting the maximum and minimum transmit power thresholds accordingly, the system optimizes the balance between ensuring adequate communication quality and maintaining system capacity. This parameter adaptation allows the same system to serve both high-quality communication needs and high-capacity requirements at different times.
2Reliability
If the maximum active set branch threshold is increased to improve soft handover gains and communication quality, then communication quality improves, but the number of occupied radio channels increases and system capacity decreases
Solution Approach 1:
The patent makes the handoff parameters dynamic by adjusting the maximum active set branch threshold based on real-time communication conditions. The Base Station Controller monitors communication quality parameters and dynamically modifies handoff thresholds, allowing the system to permit more active set branches when communication quality deteriorates and reduce them when quality is good. This dynamic adjustment resolves the contradiction between achieving soft handover gains and maintaining system capacity.
3Device complexity
If fixed power control parameters are used for all mobile stations, then system complexity is reduced, but communication quality in areas with weak CDMA signals deteriorates and call-drop rate increases
Solution Approach 1:
The patent applies local quality by tailoring power control parameters to specific mobile stations based on their individual communication conditions. Instead of using uniform fixed parameters for all users, the system adjusts parameters locally for each mobile station according to its reported communication quality, signal strength, and location. This localized adaptation improves communication quality for users in weak signal areas while maintaining manageable system complexity through automated parameter selection.
Solution Approach 2:
The patent implements feedback mechanisms where mobile stations continuously report communication quality parameters (such as frame error rate and signal strength) to the Base Station Controller. This feedback loop enables the controller to adjust power control parameters in real-time based on actual communication conditions, resolving the contradiction between parameter management complexity and communication quality by using automated feedback-driven adaptation.
Data Source
AI summary
A method for improving communication quality in a CDMA system includes: storing, groups of quality control parameters for a BS covered by the BSC; adopting, by the BS and an MS covered by the BS, one of the groups of the quality control parameters to interact with each other when the MS sets up a call; monitoring, during the call, communication quality parameters reported by the BS or by the MS; and selecting one of the groups of the quality control parameters according to the communication quality parameters and transmitting the group of the quality control parameters selected to the BS or the MS. A system and a BSC are also disclosed by the embodiments of the present invention. The solution provided by the embodiments of the present invention may improve the communication quality in areas with weak signals.