Adaptive HPLMN Scanning for Mobile Station Power Reduction

The patent applies dynamics by making the scan frequency adaptive rather than fixed. The mobile station dynamically adjusts the HPLMN scan interval based on detected mobility states (stationary, slow-moving, fast-moving) and network conditions. When the device is stationary or in stable network conditions, scan frequency is reduced to save power. When mobility increases or network conditions change, scan frequency increases to maintain reliability. This dynamic adjustment resolves the contradiction between maintaining reliable network selection and reducing power consumption.

The patent changes the parameter of scan frequency based on detected conditions. By monitoring mobility indicators (such as cell reselection frequency, signal strength changes) and network parameters, the system adjusts the HPLMN scan interval parameter. When parameters indicate stable conditions (low mobility, strong signal), the scan interval is extended. When parameters indicate changing conditions (high mobility, weak signal), the scan interval is reduced. This parameter adaptation allows the system to maintain reliability while minimizing unnecessary power consumption.

The patent implements dynamic scan interval adjustment based on the mobile station's operational state. When roaming, the system continuously monitors network conditions and mobility patterns to determine optimal scan frequency. During periods of stable roaming with no indication of returning to HPLMN coverage, scan intervals are extended to conserve battery life. When conditions suggest potential HPLMN availability (signal strength changes, cell reselection patterns), the system dynamically increases scan frequency to maintain connectivity. This dynamic behavior extends battery life while ensuring connectivity is maintained when needed.

The patent uses periodic scanning with variable periods rather than continuous scanning. The mobile station performs HPLMN scans at scheduled intervals rather than continuously monitoring. The period between scans is adjusted based on detected conditions - longer periods when stable and roaming, shorter periods when conditions change. This periodic approach with adaptive timing maintains network connectivity while significantly reducing power consumption compared to continuous monitoring, directly addressing the battery life concern.

The patent applies partial monitoring by selectively scanning for HPLMN based on detected conditions rather than continuously monitoring all frequencies. The system performs partial scans focused on relevant frequency bands and cells when conditions indicate HPLMN may be available. When mobility is low and network conditions are stable, the system reduces monitoring to partial checks rather than comprehensive scans. This partial action maintains adequate network selection accuracy while reducing power consumption by avoiding excessive monitoring activities.

The system uses self-service by leveraging existing measurements and information already collected during normal operation to trigger HPLMN scans. Rather than independently and continuously monitoring for HPLMN, the mobile station uses its own operational data (cell reselection events, signal strength measurements, mobility patterns) to intelligently determine when HPLMN scanning is necessary. This self-triggered approach maintains measurement precision when needed while avoiding unnecessary power consumption from continuous dedicated monitoring.