HeNB Access Control via CSG Cell Identification
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Solution Overview
Problem
Existing LTE networks face challenges in efficiently managing access control and unique identifier assignment for in-home evolved Node-B (HeNB) cells, leading to issues with access restriction and paging efficiency, particularly in scenarios where CSG cells overlap with macro-cells or have separate tracking areas.
Innovation Solution
Implementing a CSG cell identification system using a combination of CSG TA ID, HeNB ID, or cell ID, with additional bits for differentiation, allowing WTRUs to determine access based on programmed IDs and broadcasting public or private status, and employing a two-level approach for CSG cell identification and access control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single tracking area is used for both macro-cells and CSG cells, then network simplicity is maintained, but access control precision deteriorates
Solution Approach 1:
The tracking area is segmented into two distinct types: public tracking areas for macro-cells and private tracking areas for CSG cells. This segmentation allows the network to maintain simplicity at the macro level while enabling precise access control at the CSG cell level through separate tracking area identification.
2Measurement precision
If separate tracking areas are used for CSG cells, then access control precision is improved, but network complexity increases
Solution Approach 1:
The tracking area concept is made universal by applying it to both macro-cells and CSG cells, with the distinction being the type identifier. This multi-functionality allows the same tracking area mechanism to serve dual purposes: broad coverage management for macro-cells and restricted access management for CSG cells, without requiring entirely separate systems.
3Ease of manufacture
If traditional cell ID assignment is used for HeNBs, then device deployment is simplified, but access restriction capability deteriorates
Solution Approach 1:
The cell identification structure is nested with multiple levels: the tracking area code provides the outer layer for broad area identification, while the cell ID provides the inner layer for specific cell identification. This nested structure allows HeNBs to be deployed with simple local cell IDs while the parent tracking area code provides the access restriction capability, combining deployment simplicity with access control versatility.
Data Source
AI summary
A method and a wireless transmit/receive unit (WTRU), including a universal subscriber identity module (USIM), for identifying a closed subscriber group (CSG) cell are disclosed. The WTRU receives a broadcast from a cell including a cell identifier (ID). If the cell ID is associated with a CSG cell, the WTRU determines whether the CSG ID is programmed in the USIM. The cell broadcast may include a single bit information element (IE) indicating that the cell is a CSG cell. If the cell ID is a CSG ID, the cell ID may further include a plurality of fields which indicate at least one of a country, a region, an operator, and a home evolved Node-B (HeNB) number. The cell broadcast may further include a bit indicating whether the CSG cell is public or private. The cell broadcast may further include a bit indicating that emergency calls are allowed from all users.