Session State Propagation in Wireless Active Sets
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Solution Overview
Problem
In wireless communication systems, there is a need for timely propagation of session state changes to each network function serving a sector in the active set to maintain optimal service, as changes in session state attributes, such as header types or security keys, must be updated across all sectors to ensure continuous communication without service disruptions.
Innovation Solution
The implementation of an apparatus and method where an access terminal or network function queries a session master to determine if the session state has changed, and updates its copy of the session state using either an access terminal (AT) pushed-based mechanism or a timer-based mechanism, ensuring that all network functions in the active set receive the updated session state information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If session state changes are propagated to all network functions in the active set, then service continuity and QoS are maintained, but network signaling overhead and complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing the active set of network functions and maintaining session state copies at each NF before changes occur. When session state changes, the triggering NF already has the capability to notify others immediately, and receiving NFs are prepared to update their copies without delay. This pre-configuration enables rapid propagation of session state changes across all NFs in the active set, ensuring service continuity while managing signaling complexity through structured notification mechanisms.
2Speed
If session state is copied to multiple network functions for active set sectors, then handoff speed and service continuity are improved, but memory usage and information synchronization complexity increase
Solution Approach 1:
The patent implements feedback through a notification mechanism where the triggering network function sends notifications to other NFs in the active set when session state changes occur. Each receiving NF updates its session state copy based on this feedback. This feedback loop ensures all NFs maintain synchronized session state information, preventing information loss during handoffs while enabling rapid service continuity. The structured feedback mechanism manages synchronization complexity by providing clear change propagation paths.
3Stability of the object's composition
If centralized session state management is used, then consistency is maintained, but response time for session state updates increases
Solution Approach 1:
The patent applies segmentation by dividing session state management across multiple network functions in the active set. Each NF maintains a local copy of the session state rather than all NFs querying a single centralized source. When a change occurs, only the affected NFs need to be notified and update their copies, rather than propagating to all NFs in the system. This segmentation reduces update propagation time while maintaining consistency through targeted notifications to relevant NFs in the active set.
Data Source
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AI summary
A network function is configured to maintain a copy of a session state for an access terminal. The network function is further configured to query a session master to determine whether the session state has changed. The session master is configured to generate a response to the query that enables the network function to update the copy of the session state if the session state has changed. The access terminal may be configured to change the session state at a first network function and send a message to a second network function to indicate that the session state has been changed.