Selective Scanning of Active Set Sectors in CDMA Mobile Stations
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Solution Overview
Problem
Mobile stations in CDMA systems spend excessive battery power scanning multiple sectors for pilot signals, leading to increased hand-off delay and power consumption, as they currently scan all sectors in their active set without differentiation.
Innovation Solution
Implementing a dual scanning mode where the mobile station initially scans all sectors, identifies and excludes sectors with the lowest signal strengths (transparent sectors), and then operates in a second mode scanning only a subset of sectors, switching back to full scanning if a call-drop risk is detected or battery power is low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile station scans all sectors in the active set, then the hand-off reliability is improved, but the battery power consumption increases
Solution Approach 1:
The patent divides the active set of sectors into two segments: scanned sectors and transparent sectors. The mobile station maintains the active set but selectively scans only a subset of sectors while treating others as transparent. This segmentation allows the system to maintain hand-off reliability by monitoring key sectors while reducing power consumption by excluding others from scanning operations.
Solution Approach 2:
The patent implements partial scanning by scanning only a subset of sectors rather than all sectors in the active set. The mobile station performs scanning operations on selected sectors while using stored information for transparent sectors, applying partial action to reduce power consumption while maintaining sufficient hand-off monitoring capability.
2Measurement precision
If the mobile station scans all sectors in the active set, then the hand-off detection accuracy is improved, but the hand-off delay increases
Solution Approach 1:
The patent segments the scanning process into immediate scanning of selected sectors and deferred processing of transparent sectors using stored information. This segmentation reduces the time required for complete hand-off detection while maintaining accuracy by prioritizing sectors that require immediate monitoring.
Solution Approach 2:
The patent applies preliminary action by pre-storing information about transparent sectors before the scanning process begins. This allows the mobile station to quickly reference stored information during hand-off detection without performing time-consuming scanning operations on all sectors, thereby reducing hand-off delay while maintaining detection accuracy.
3Adaptability or versatility
If the active set contains more sectors, then the communication coverage is improved, but the scanning complexity increases
Solution Approach 1:
The patent segments the active set into scanned and transparent sectors, reducing scanning complexity while maintaining comprehensive coverage. The mobile station manages this segmented structure by maintaining separate tracking for scanned sectors and stored information for transparent sectors, simplifying the overall scanning process.
Solution Approach 2:
The patent applies local quality by assigning different scanning priorities to different sectors based on their characteristics. Scanned sectors receive full scanning resources while transparent sectors use stored information, creating differentiated quality levels that reduce overall complexity while maintaining adequate coverage for all sectors.
Data Source
AI summary
Exemplary methods and systems are disclosed that may help a mobile station to conserve power by reducing the number of active sectors being scanned in certain scenarios. An exemplary method involves a mobile station (a) initially operating in a first scanning mode, wherein operation in the first scanning mode comprises the mobile station scanning all sectors in an active set comprising a plurality of sectors; (b) determining signal strength of each sector in the active set; (c) selecting, from the active set, one or more transparent sectors having the lowest signal strengths relative to the other sectors in the active set; and (d) operating in a second scanning mode, wherein operation in the second scanning mode comprises the mobile station scanning a subset of the sectors in the active set, wherein the subset excludes the one or more transparent sectors.