Trunking Group Call Decryption During Cell Switching
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Solution Overview
Problem
In mobile communication, when a user equipment switches from one cell to another during a group call, the inconsistent encryption parameters and unsynchronized encryption contexts cause a longer time delay in service interruption, affecting user experience.
Innovation Solution
A decryption method that monitors group call data in the current cell, obtains the hyper frame number, and when switching to a target cell, derives a reasonable interval range for the hyper frame number to traverse and decrypt the group call data, ensuring consistent session information and reducing service interruption time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption parameters are applied per cell independently, then encryption security is maintained, but service interruption time increases during cell switching
Solution Approach 1:
The patent applies preliminary action by pre-obtaining and caching encryption parameters from neighboring target cells before cell switching occurs. The user equipment stores encryption parameters of adjacent cells in advance, so when switching happens, the parameters are already available immediately, eliminating the time delay that would otherwise occur during parameter acquisition after switching.
Solution Approach 2:
The patent implements preliminary synchronization of encryption contexts for neighboring cells with the current cell's encryption context. By synchronizing these contexts beforehand, the user equipment can seamlessly continue decryption operations after cell switching without experiencing service interruption, as the encryption state is already aligned.
2Duration of action of moving object
If encryption contexts are synchronized across cells, then service continuity improves, but system complexity increases
Solution Approach 1:
The patent applies local quality by implementing encryption context synchronization only for neighboring target cells that are adjacent to the current cell, rather than synchronizing across the entire network. This localized approach maintains service continuity for cell switching while limiting the complexity increase to only the relevant local area.
Solution Approach 2:
The patent uses the base station as an intermediary to manage and distribute encryption parameters and context synchronization information to user equipment. This intermediary approach simplifies the overall system complexity by centralizing the coordination function at the base station level rather than requiring complex peer-to-peer synchronization mechanisms between user equipment and multiple cells.
Data Source
AI summary
The invention provides a decryption method for a trunking group call and a user equipment. The method includes: monitoring group call data in a current cell and obtaining a hyper frame number being a first hyper frame number; when switching from the current cell to a target cell, obtaining the group call data and obtaining an interval range of a hyper frame number of the target cell according to the first hyper frame number, the hyper frame number of the target cell being a second hyper frame number; traversing the second hyper frame number according to the interval range of the second hyper frame number, obtaining a plaintext, and comparing group call session information contained in the plaintext with the group call data of the current cell; and if consistent, decryption by traversing the second hyper frame number being successful, carrying out a decryption operation according to the second hyper frame number.