Mobile Equipment Time Tracking During Cell Handover
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing time tracking systems in mobile equipment fail to maintain accurate timing information when handover occurs from one cell to another in a cellular communications system, as the cellular-GPS time relationship (CGTR) is valid only for one cell and cannot be used in a different cell.
Innovation Solution
A method and timing circuit for mobile communications devices to determine and maintain the relationship between time measured in a first cell and a timing system, allowing for continuous accurate GPS timing information delivery by starting and stopping a counter at known times in both cells, enabling the calculation of the CGTR for the new cell during handover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the mobile equipment uses the cellular-GPS time relationship (CGTR) from the currently camped cell for Fine Time Assistance, then the time-to-fix and location accuracy are improved, but the timing information cannot be maintained when handover occurs to another cell
Solution Approach 1:
The mobile equipment performs preliminary actions by determining the CGTR relationship in advance during the first cell's operation, storing it in memory, and using it to generate accurate strobos before handover occurs. This preliminary determination of the time relationship enables continuous accurate timing without requiring real-time network assistance during handover transitions.
Solution Approach 2:
The patent introduces an intermediary mechanism where the mobile equipment itself determines and maintains the CGTR relationship independently, rather than relying solely on network-provided timing information. The equipment uses its own internal counter and stored time relationships to bridge the gap between cells, acting as an intermediary that preserves timing continuity during handover.
2Ease of operation
If the mobile equipment relies on network-provided CGTR information for time tracking, then the setup is simple, but the timing information is lost during cell handover
Solution Approach 1:
The mobile equipment performs self-service by independently determining and maintaining the CGTR relationship using its own internal resources (counter, memory, and processing units). Rather than passively relying on network-provided timing information that is lost during handover, the equipment actively determines the time relationship itself and continues to use it autonomously during cell transitions.
Solution Approach 2:
The equipment preliminarily determines the CGTR relationship during the first cell's operation and stores it in memory before handover occurs. This preliminary action ensures that the timing information is preserved and can be immediately applied in the second cell without requiring re-determination or network assistance during the handover transition.
3Reliability
If the mobile equipment determines the CGTR relationship independently without network assistance, then timing continuity during handover is maintained, but the complexity of the timing circuit increases
Solution Approach 1:
The mobile equipment implements self-service timing by using its existing counter and processing capabilities to determine and maintain the CGTR relationship independently. The equipment leverages its own internal resources rather than requiring external network assistance, thereby maintaining timing continuity while using only the necessary additional functionality already present in the device.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method is disclosed for time tracking in a mobile equipment. The mobile equipment determines a relationship between time as measured in a serving cell of a cellular system and time as measured in a satellite positioning system. This is referred to as the cellular-GPS time relationship, or CGTR, for that cell. When a handover is imminent, a time count is started, at a particular known time instant as measured in the serving cell of the cellular system. The known relationship allows this to be translated into a time as measured in the satellite positioning system. After the handover, the time count is stopped at a particular time instant as measured in the new serving cell of the cellular system. Meanwhile, the time at the same instant, as measured in the satellite positioning system, can be obtained by adding the counted time to the count start time as measured in the satellite positioning system. Thus, even though cellular times between neighbouring cells are not synchronized, and hence there is no predetermined relationship between the CGTRs for the two cells, the CGTR for the new cell can be determined.