Soft Handover Cell Identification via Scrambling Code Lists
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Solution Overview
Problem
In CDMA-based mobile telecommunication systems, detected set cells without known cell identities pose challenges for inclusion in the active set due to the lack of mandatory cell identity reporting, leading to difficulties in identifying and adding them, especially when multiple cells share the same scrambling code.
Innovation Solution
A method is implemented where the network creates a list of cells by scrambling codes, establishes temporary neighbor relations based on received measurement reports, and performs uplink synchronization to confirm and convert temporary relations to permanent, allowing detected set cells to be added to the active set even without initial cell identity knowledge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the network uses scrambling code only for identifying detected set cells, then the system can operate without mandatory cell identity reporting, but it becomes difficult to uniquely identify and add cells to the active set when multiple cells share the same scrambling code
Solution Approach 1:
The patent introduces a temporary neighbor relation as an intermediary mechanism between the mobile terminal's measurement report and the network's cell identification process. This temporary relation allows the network to provisionally associate a detected cell with a cell in the active set that shares the same scrambling code, enabling further verification through uplink synchronization before final confirmation. This mediator resolves the contradiction by allowing operation with scrambling code only while maintaining accurate cell identification through the verification process.
Solution Approach 2:
The patent implements preliminary action by establishing a temporary neighbor relation before final cell identification is confirmed. The network proactively creates this temporary association based on scrambling code matching, allowing the system to prepare for potential cell addition while maintaining the option to verify through uplink synchronization. This preliminary step enables the system to operate without mandatory cell identity reporting while still ensuring accurate cell identification before permanent addition to the active set.
2Reliability
If the network requires mobile terminal to report cell identity, then detected set cells can be uniquely identified and added to active set, but the system complexity increases and compatibility with release '99 specification is reduced
Solution Approach 1:
The patent applies partial action by requiring cell identity reporting only when necessary for unique cell identification, rather than making it mandatory in all cases. The system first attempts to identify cells using scrambling code alone, and only requests additional cell identity information when multiple cells share the same scrambling code and ambiguity exists. This partial approach maintains reliability for cell identification while minimizing the increase in system complexity and preserving compatibility with release '99 specification.
3Adaptability or versatility
If the network creates and maintains comprehensive neighbor cell lists, then all possible cells can be monitored and added to active set, but the neighbor cell planning requirements and system complexity increase
Solution Approach 1:
The patent implements self-service by enabling the mobile terminal to autonomously detect and report cells in the detected set based on its own measurements, without requiring the network to pre-configure comprehensive neighbor cell lists. The terminal independently identifies cells and reports them with their scrambling codes, allowing the network to dynamically build the active set based on actual measurements rather than static planning. This self-service approach enhances mobility functionality while reducing neighbor cell planning requirements and system complexity.
Data Source
AI summary
The present invention relates to a method and arrangements for including a detected cell, i.e. a cell not identified by the network, in an active set, i.e. the set comprising the base stations simultaneously connected to the same mobile terminal in soft handover. The method comprises the steps of:—receiving a measurement report comprising a detected set cell from a mobile terminal located in a first cell:—providing (301) a list (L1) for the first cell in the network with cells not defined as neighbouring cells to the first cell, wherein the cells in the list (L1) are grouped based on their scrambling codes;—identifying (302) the scrambling code of the detected set cell;—creating (303) a temporary relation between one of the cells in the list (L1), having an identical scrambling code as the detected set cell, and one cell in the AS;—adding (304) the one of the cells in the list (L1), having an identical scrambling code as the detected set cell, to the active set.