HNB Access Control via CSG Broadcast and URA Management
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Solution Overview
Problem
Current mobility management and access control mechanisms for Home Node B (HNB) deployments are inefficient, leading to increased signaling load and poor cell reselection in wireless communications, especially when WTRUs roam through areas with high concentrations of HNBs that do not have them in their closed subscriber group (CSG), and pose challenges for emergency services and flexible HNB deployments.
Innovation Solution
A method and apparatus that provide HNB access restriction information to WTRUs, allowing access only to permitted devices, trigger cell reselection measurements even when signal strength is above threshold, and dynamically manage URA lists to account for HNB relocation, ensuring WTRUs preferentially select their preferred HNB cells and reducing unnecessary measurements in inaccessible cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If legacy mobility management signaling is used for access control, then WTRUs can attempt to access HNB cells, but signaling load increases due to multiple registration attempts in areas with high HNB concentration
Solution Approach 1:
The patent applies preliminary action by providing HNB access restriction information to WTRUs before they attempt to access HNB cells. This allows WTRUs to identify and avoid HNB cells where they are not members of the CSG, preventing unnecessary registration attempts and reducing signaling load in areas with high HNB concentration.
2Ease of operation
If cell reselection measurements are only triggered when signal strength is below threshold, then WTRUs conserve energy, but WTRUs may not select preferred HNB cells even when in vicinity
Solution Approach 1:
The patent applies local quality by differentiating the cell reselection behavior based on WTRU membership status. For WTRUs that are members of the CSG, the system triggers cell reselection measurements even when signal strength is above threshold, ensuring they can select their preferred HNB cell. This localized adjustment applies only to specific WTRUs in specific conditions rather than universally.
3Adaptability or versatility
If HNBs are deployed flexibly without fixed locations, then deployment flexibility increases, but URA-based paging and location tracking become ineffective
Solution Approach 1:
The patent introduces HNB access restriction information as an intermediary mechanism that bridges the gap between flexible HNB deployment and effective location tracking. By providing this information to WTRUs, the system enables WTRUs to identify their preferred HNB and maintain location awareness even when HNBs are not tied to fixed URAs, thus preserving location information despite deployment flexibility.
Data Source
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AI summary
A method comprising a HNB transmitting an indication to one or more wireless transmit/receive units (WTRU) that the cell of the HNB is reserved, transmitting a closed subscriber group, CSG, broadcast, and receiving a connection request from at least one WTRU that ignored the indication that the cell is reserved based on the CSG broadcast. The indication may indicate that legacy WTRUs are barred from accessing the cell. The CSG broadcast may be configured as being unable to be interpreted by legacy WTRUs that do not support HNB features.