Private LTE Tracking Area Collision Avoidance
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Solution Overview
Problem
Private LTE networks face challenges with unique Tracking Area Codes (TACs) allocation, leading to network collisions and denial-of-service attacks due to shared identifiers, causing UEs to be incorrectly rejected and potentially blocked from their own networks.
Innovation Solution
User Equipment (UE) maintains lists of allowed and forbidden TACs and ECGI ranges, using the CBRS network name to differentiate between networks, and relays rejected TAC information to the serving cell for collision detection and mitigation, allowing for TAC re-planning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If shared PLMN ID (SHNI) is used for private LTE networks, then network deployment flexibility is improved, but network identification accuracy deteriorates causing UE camping on incorrect networks
Solution Approach 1:
The patent segments the network identification process by introducing multiple hierarchical identifier layers (PLMN ID, TAC, ECGI, CSG ID) that work together to uniquely identify networks. Instead of relying on a single PLMN ID, the system divides identification across multiple parameters, allowing shared PLMN IDs to coexist with unique network differentiation through combined identifier tuples.
Solution Approach 2:
The patent introduces tracking area codes (TAC) and ECGI as intermediary identifiers that mediate between the shared PLMN ID and the specific network. These intermediaries provide an additional layer of differentiation, allowing UEs to distinguish between networks using the same PLMN ID by examining the combined (PLMN ID, TAC, ECGI) tuple.
2Measurement precision
If unique PLMN IDs are assigned to every private LTE operator, then network identification accuracy is improved, but regulatory requirements cannot be met as private networks cannot offer public services
Solution Approach 1:
The patent segments the identification hierarchy so that PLMN ID operates at one level while TAC, ECGI, and CSG ID operate at lower levels. This segmentation allows the system to comply with regulatory requirements by using shared PLMN IDs (as private networks cannot obtain unique ones) while maintaining accurate network identification through the combined identifier approach.
Solution Approach 2:
The patent adds additional dimensions to the identification space by introducing TAC and ECGI as supplementary identifier layers. Instead of relying solely on the PLMN ID dimension, the system creates a multi-dimensional identification space where networks are distinguished by their position in the (PLMN ID, TAC, ECGI) multidimensional space.
3Ease of manufacture
If tracking area codes are not managed to be unique, then identifier allocation simplicity is improved, but network collision occurs causing denial-of-service attacks and incorrect UE rejection
Solution Approach 1:
The patent implements preliminary action by having UEs proactively maintain forbidden TAC lists and perform collision detection before attempting network access. When registration failures occur, UEs pre-record the problematic TACs and ECGIs, preventing future attempts to access colliding networks and avoiding denial-of-service conditions.
Solution Approach 2:
The patent establishes feedback loops where UEs monitor registration success/failure, record TAC and ECGI information from failed attempts, and use this feedback to update their forbidden lists. This feedback mechanism allows the system to adapt to TAC collisions dynamically, improving network access reliability without requiring centralized TAC management.
4Productivity
If UEs attempt registration in all tracking areas, then network access completeness is improved, but battery consumption increases and incorrect networks are selected
Solution Approach 1:
The patent applies preliminary action by having UEs pre-populate forbidden TAC lists based on previous registration failures before attempting new network access. This preliminary filtering prevents UEs from wasting battery power attempting to register in known problematic tracking areas, while still allowing access to valid networks.
Solution Approach 2:
The patent implements partial action by having UEs attempt registration only in tracking areas that are not in their forbidden lists, rather than exhaustively attempting all possible TACs. This selective approach reduces unnecessary registration attempts and battery consumption while maintaining access to legitimate networks.
Data Source
AI summary
A determination is made that a registration attempt by a UE with a cell of a wireless network has failed when the UE is in a current tracking area. The UE updates a first list with indications(s) corresponding to the cell and an indication of the current tracking area, and the UE uses the first list for additional registration attempts. A network node sends, toward the UE, a request for the UE to store information, the storing to be in response to registration attempts by the UE with cells of the wireless network having failed while in corresponding tracking areas. The information is to include indication(s) corresponding to the cells and corresponding indication(s) of the tracking areas for the cells. The network node receives, in response to a successful secure connection having been performed between the wireless network and the UE, the information from the user equipment.