Inter-system Handoff Minimization via Preliminary Dormant Connection
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Solution Overview
Problem
Current telecommunications systems face challenges in efficiently performing inter-system handoffs between legacy circuit-switched or packet-switched networks and next-generation LTE networks, particularly in minimizing the break time during handoffs between HRPD and LTE access networks.
Innovation Solution
The implementation of a method and system that includes a new Ax interface for Layer 2 signaling to prepare resources and convey essential information like the Inter-System Source Access Network Identifier and security status, allowing for optimized handoffs by establishing a dormant connection and pre-setting an A10 connection before breaking the original radio connection, thereby reducing the break time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mobile unit performs inter-system handoff between HRPD and LTE networks, then the mobile unit can maintain continuous connectivity and access services, but the handoff process requires significant break time during which the mobile unit is disconnected from both networks
Solution Approach 1:
The patent applies preliminary action by establishing a dormant connection in the target HRPD network before breaking the source LTE connection. The mobile unit performs initial HRPD access and establishes a dormant A10 connection with the PDSN prior to actual handoff execution, so that when the LTE connection is broken, the HRPD connection is already ready to immediately carry traffic, thereby minimizing service interruption time
Solution Approach 2:
The patent uses an intermediary approach by introducing a dormant connection state as a buffer between the source and target networks. The mobile unit maintains simultaneous connections to both LTE and HRPD networks during the transition period, with the HRPD connection in dormant state serving as an intermediary that can immediately take over when the LTE connection is broken, avoiding direct break-before-make handoff
2Loss of time
If the mobile unit establishes a new connection in the target HRPD network before breaking the source LTE connection, then the handoff break time is minimized, but additional signaling and resource allocation are required
Solution Approach 1:
The mobile unit performs preliminary actions by executing initial HRPD access procedures and establishing a dormant A10 connection with the PDSN before the actual handoff. This preliminary connection setup includes obtaining HRPD channel assignments and establishing packet data protocol context, but keeps the connection dormant with minimal resource allocation until handoff is triggered
Solution Approach 2:
The patent applies partial action by establishing only the essential dormant connection components needed for immediate handoff takeover, rather than fully activating all HRPD services. The dormant connection includes basic packet data bearers and PDSN registration, but omits full service activation, thereby reducing signaling overhead while still achieving the handoff time reduction goal
3Productivity
If the mobile unit performs inter-system handoff, then load balancing between HRPD and LTE networks can be achieved, but the handoff process requires authentication and security verification
Solution Approach 1:
The patent applies preliminary action by performing HRPD authentication and security verification during the initial dormant connection establishment phase, before the actual handoff occurs. The mobile unit completes HRPD network authentication, obtains security credentials, and establishes the A10 connection with PDSN in advance, so that when handoff is executed, authentication is already complete and no additional authentication time is needed during the critical handoff transition
Data Source
AI summary
Systems and methods according to these exemplary embodiments provide for methods and systems for handing off user equipment between different access systems, e.g., a high rate packet data (HRPD) system and a long term evolution (LTE) system. Resources to be used in the target system can be allocated prior to breaking the serving radio connection to minimize “break before make” time associated with the handoff.