Dual Transfer Mode Handover Coordination via Shared Identifier
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Solution Overview
Problem
Conventional dual transfer mode handover mechanisms in mobile phone systems drop packet switched resources during handover, causing interruptions to real-time services like video streaming and gaming, as they prioritize circuit switched connections and lack effective coordination between packet switched and circuit switched signalling domains.
Innovation Solution
A method for dual transfer mode handover that uses a unique identifier for both circuit switched and packet switched networks to coordinate handover requests and commands, ensuring simultaneous resource allocation and minimizing service interruptions by synchronizing messages across both domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CS handover mechanism is used in dual transfer mode, then circuit switched connection is maintained, but packet switched resources are dropped causing service interruption
Solution Approach 1:
The patent merges the CS handover and PS handover procedures into a single coordinated process. Both handovers share common signaling steps, message structures, and resource allocation procedures, allowing them to occur simultaneously rather than sequentially. This integration ensures that PS resources are maintained throughout the handover process while CS connection is established, eliminating service interruptions.
Solution Approach 2:
The patent introduces a handover coordination mechanism that acts as an intermediary between the CS and PS domains. This coordination entity manages the shared signaling process, ensures proper synchronization between the two handovers, and coordinates resource allocation in both domains, enabling seamless dual transfer mode handover without dropping PS resources.
2Ease of manufacture
If separate CS and PS handovers are performed, then each domain can be optimized independently, but coordination complexity increases and service interruption occurs
Solution Approach 1:
The patent combines the CS and PS handover procedures into a unified process with shared signaling messages and common coordination logic. This reduces the overall complexity compared to managing two separate handover processes, while still allowing domain-specific optimizations through the standardized interface defined in the GMM and NAS layers.
3Ease of operation
If PS resources are dropped during handover, then conventional CS handover simplicity is maintained, but real-time packet services experience interruptions
Solution Approach 1:
The patent ensures continuous PS resource allocation throughout the handover process. Instead of dropping and re-establishing PS resources, the system maintains active PS bearers during the CS handover execution, allowing real-time packet services to continue without interruption. This is achieved through coordinated resource management in both source and target base station subsystems.
Data Source
Figure 1~2B
AI summary
A method of dual transfer mode handover between a source base station (2) and a target base station (3) comprises preparing messages (6, 7) to a circuit switched (CS) network (4) and to a packet switched (PS) network (5) indicating a requirement for handover; adding an identifier (18) to each message, wherein the identifier is the same for both networks; sending each message to its respective network; allocating resources in each network and signalling (8, 9) to the target base station (3) that a handover is requested. CS and PS requests are coordinated at the target base station, based on the identifier; an acknowledgment (10, 11) is sent to the respective networks (5, 4); and handover commands (12, 13) from each network are coordinated at the source base station (2), based on the identifier, then a dual transfer mode handover command (14) is sent to the mobile terminal (1).