LTE-CDMA2000 Interworking via Multi-System Signaling
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Solution Overview
Problem
Current LTE specifications only support interworking between a single LTE system and a single CDMA2000 system, failing to accommodate scenarios where an LTE system has overlapping radio coverage with multiple CDMA2000 systems of the same type, limiting handover and fallback services.
Innovation Solution
The implementation allows user equipment (UE) to select and signal multiple CDMA2000 systems for handover and fallback services, using enhanced signaling mechanisms to route connections between LTE and CDMA2000 systems, enabling interworking between a single LTE system and multiple CDMA2000 systems by broadcasting and mapping CDMA2000 System Identifiers and specific parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current LTE specifications support interworking between a single LTE system and a single CDMA2000 system, then the system complexity is low and implementation is simple, but the adaptability is limited and cannot accommodate overlapping radio coverage scenarios with multiple CDMA2000 systems
Solution Approach 1:
The patent segments the CDMA2000 system information into multiple individual system identifiers (each representing a separate CDMA2000 system) that can be independently selected and managed. The UE can identify and connect to specific CDMA2000 systems by selecting from multiple system identifiers broadcast by the LTE system, allowing support for multiple CDMA2000 systems without treating them as a single monolithic system.
Solution Approach 2:
The patent introduces a new dimension of system identification by adding multiple CDMA2000 system identifiers to the LTE broadcast information. This dimensional expansion allows the LTE system to reference and manage multiple CDMA2000 systems simultaneously through enhanced signaling mechanisms, transforming the single-system limitation into a multi-system capability.
2Reliability
If the LTE system broadcasts and maps multiple CDMA2000 System Identifiers, then the interoperability and service continuity are improved, but the signaling complexity and information overhead increase
Solution Approach 1:
The patent applies preliminary action by having the LTE system pre-broadcast multiple CDMA2000 system identifiers and relevant parameters before handover or fallback is needed. The UE can perform measurements and select the most appropriate CDMA2000 system in advance, reducing last-minute signaling requirements and improving service continuity during actual handover execution.
Solution Approach 2:
The patent uses copying by having the LTE system broadcast reference information (system identifiers, frequency, bandwidth) that represents the characteristics of multiple CDMA2000 systems. This copied information allows the UE to identify and connect to the appropriate system without requiring extensive real-time signaling, reducing information overhead while maintaining reliability.
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AI summary
A method at a user equipment in an LTE system includes selecting one of a number of CDMA systems, and signaling indication(s) of the selected CDMA system to a network element. The network element receives indication(s) of CDMA system(s), which correspond to requested action(s) by a UE. The network element routes information corresponding to the requested action(s) to the CDMA system(s). Another network element in the LTE system signals to the UE indications of a mapping of a number of CDMA systems to associated ones of LTE system(s). The other network element receives signaling from the UE including indication(s) of selected CDMA system(s) selected by the UE.