Resource Allocation During Tune-Away for Wireless Handoffs
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Solution Overview
Problem
Mobile stations with single receive chains cannot simultaneously communicate with base stations using disparate technologies or communication protocols, leading to challenges in handoff processes without data loss or service disruption.
Innovation Solution
A method and apparatus for resource allocation during a tune-away procedure, where resource assignments are implicitly expired and re-established at frame boundaries, allowing for communication with disparate access points, and caching data for seamless service continuation across technology and frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a mobile station uses a single receive chain to communicate with base stations using disparate technologies or communication protocols, then the device complexity is reduced, but the handoff process cannot occur simultaneously across multiple frequencies or technologies leading to service disruption
Solution Approach 1:
The system performs preliminary actions by scheduling tune-away periods in advance and pre-coordinating resource allocations with target base stations before the mobile station needs to switch frequencies. This allows the mobile station to temporarily tune away to evaluate alternative base stations without disrupting ongoing service, as resource assignments are prepared beforehand to maintain continuity.
Solution Approach 2:
The system implements periodic tune-away opportunities where the mobile station temporarily switches frequencies at scheduled intervals to monitor pilot signals from base stations using disparate technologies. This periodic action allows the single receive chain to evaluate multiple technologies without requiring simultaneous reception capabilities, while maintaining service continuity through coordinated resource management.
2Reliability
If resource assignments are maintained during tune-away periods, then service continuity is preserved, but resource allocation efficiency decreases due to idle resource assignments
Solution Approach 1:
The system dynamically adjusts resource assignments based on the mobile station's tune-away schedule. Resource assignments are temporarily suspended or reallocated to other mobile stations during tune-away periods, and automatically restored when the mobile station returns. This dynamic approach maintains service continuity while optimizing resource utilization by preventing idle resource assignments during periods when the mobile station cannot receive transmissions.
Solution Approach 2:
The system enables self-service through automatic resource reassignment and restoration mechanisms that operate without manual intervention. When a mobile station enters tune-away mode, the system automatically reallocates its resources to other users, and upon return, automatically restores the original resource assignments, thereby maintaining both service continuity and resource efficiency.
3Reliability
If the mobile station monitors multiple frequencies simultaneously, then handoff preparation is improved, but the device complexity increases requiring multiple receive chains
Solution Approach 1:
The system performs preliminary handoff preparation by scheduling tune-away periods in advance where the mobile station can monitor pilot signals from target base stations. During these pre-scheduled intervals, the mobile station temporarily tunes away from its current frequency to evaluate alternative base stations using disparate technologies, enabling handoff preparation without requiring simultaneous multi-frequency monitoring capabilities.
Solution Approach 2:
The system implements periodic tune-away opportunities that allow the mobile station to temporarily switch frequencies and monitor pilot signals from base stations using different technologies. This periodic multi-frequency monitoring approach enables comprehensive handoff preparation while maintaining a simple single receive chain architecture, as the station only needs to switch frequencies periodically rather than simultaneously.
Data Source
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AI summary
A resource assignment method during a tune-away procedure comprises determining a first instance in time that a tune-away will initiate with respect to an access terminal, determining a second instance in time that corresponds to a latest frame boundary associated with the access terminal prior to the instance in time that the tune-away initiates, and determining resource assignment parameters associated with the access terminal and implementing the resource assignment parameters at the second instance in time. The method can further comprise ceasing communications to the access terminal over a forward link at the second instance in time and discontinuing monitoring reverse link control channels associated with the access terminal at the second instance in time.