Adaptive Server Selection via Data Source Control for Wireless Handoff
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Solution Overview
Problem
Wireless communication systems face challenges in reducing service outage during handoff processes, particularly in high-rate packet data systems, which can lead to delays and service degradation for delay-sensitive applications like VoIP due to the time required for sector switching and potential channel imbalances.
Innovation Solution
The introduction of a Data Source Control (DSC) channel and Data Rate Control (DRC) channel mechanisms, including credit-based sector evaluation and multicast strategies, to minimize service outage by anticipating and preparing sector changes, ensuring seamless data transfer during handoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sector switching is performed during handoff in high-rate packet data systems, then the system can maintain connectivity and support multiple users, but service outage occurs during the switching process causing delays and service degradation
Solution Approach 1:
The patent applies preliminary action by evaluating and preparing target sectors before actual handoff occurs. The system uses the DSC channel to identify candidate sectors in advance, calculates channel imbalances beforehand, and prepares credit-based metrics to predict which sector will provide the best service. This advance preparation allows the handoff to execute more quickly with minimal service interruption, as the target sector is already evaluated and ready to接管 service immediately when selected.
2Device complexity
If traditional sector selection methods are used without anticipating channel imbalances, then the handoff process is simpler, but service outage increases due to lack of preparation for sector changes
Solution Approach 1:
The system performs preliminary evaluation of target sectors by calculating channel imbalances and assigning credits to candidate sectors before handoff. The DSC channel continuously monitors and identifies potential target sectors, preparing quality metrics and channel balance assessments in advance. This allows the network to anticipate which sector will provide optimal service, reducing service outage duration while maintaining manageable complexity through automated credit-based evaluation.
Solution Approach 2:
The patent implements feedback mechanisms where the system continuously monitors channel conditions, calculates imbalances, and updates credit metrics for different sectors. This feedback loop provides real-time information about sector quality and channel balance, enabling dynamic handoff decisions. The feedback from channel quality measurements and credit calculations allows the system to adapt to changing conditions and select the best target sector, reducing service outage while maintaining controlled complexity through systematic evaluation.
3Loss of time
If the system evaluates and prepares multiple candidate sectors in advance, then service outage is reduced, but the complexity of sector evaluation and credit calculation increases
Solution Approach 1:
The system applies self-service by implementing automated credit-based evaluation that continuously and autonomously assesses candidate sectors. The DSC channel and associated algorithms automatically calculate channel imbalances, assign credits to sectors based on their quality metrics, and update evaluations without requiring manual intervention or complex external processing. This self-service mechanism reduces service outage through continuous monitoring while managing complexity through standardized, repeatable evaluation procedures that operate autonomously.
Data Source
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AI summary
Embodiments disclosed herein relate to methods and systems for providing adaptive server selection in wireless communications. An access terminal may be configured to determine a forward link quality metric associated with each of a plurality of sectors serviced by a plurality of access points; assign credits to each sector in relation to the forward link quality metric; and change a data source control (DSC) value if the credits accumulated for a non-serving sector at a DSC change boundary is greater than a predetermined threshold, where the non-serving sector and the serving sector for the access terminal belong to different cells. The access terminal may be further configured to change a data rate control (DRC) cover in accordance with the DSC change. The use of DSC may provide an early indication of handoff, thereby allowing the service outage associated with server switching to be substantially reduced.