5G Scrambling Sequence Update via HARQ Feedback
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Solution Overview
Problem
Current 5G wireless communication systems provide limited security for data transmissions, making them vulnerable to eavesdropping, as existing security protocols are not efficiently secure enough, especially against physical layer attacks.
Innovation Solution
Implementing physical layer security (PLS) by using transport blocks (TBs) to derive scrambling sequences based on Hybrid Automatic Repeat Request (HARQ) feedback, where successfully delivered TBs are used to encrypt subsequent TBs, reducing the risk of data being maliciously decoded by eavesdroppers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical layer security is implemented using TBs to derive scrambling sequences based on HARQ feedback, then security against eavesdropping is improved, but device complexity increases
Solution Approach 1:
The patent changes the scrambling sequence parameters dynamically based on HARQ feedback. Specifically, the scrambling initialization value is updated using the formula c_init = N_ID_scrambling + n_HARQ, where n_HARQ changes based on successful TB deliveries. This parameter change approach enables security enhancement without requiring fundamentally new system architecture, thus managing device complexity while improving security.
Solution Approach 2:
The system uses its own transmission data (successfully delivered TBs) to generate the security mechanism. The HARQ feedback, which is already generated for retransmission control, is repurposed to derive scrambling sequences for security. This self-service approach avoids additional dedicated security signaling or external key distribution mechanisms, reducing overall system complexity while achieving security.
2Reliability
If dynamic scrambling sequence updates are performed based on HARQ feedback, then security against malicious decoding is improved, but processing time increases
Solution Approach 1:
The patent merges the security function with the existing HARQ processing function. The same HARQ feedback that controls retransmissions is simultaneously used to update scrambling sequences for security. By combining these two functions, the patent avoids separate security processing steps that would increase processing time, thus reducing time loss while improving security against malicious decoding.
3Device complexity
If existing security protocols are used for data transmissions, then device complexity is kept low, but security against physical layer attacks is insufficient
Solution Approach 1:
The patent introduces HARQ feedback as an intermediary element that bridges the existing transmission protocol and security requirements. Instead of implementing a completely new security protocol, the system uses the intermediary HARQ feedback mechanism to derive scrambling sequences. This intermediary approach provides physical layer security while building upon existing protocols, thus avoiding excessive complexity increase.
Data Source
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AI summary
An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: determine (1006) whether at least one transport block has been successfully delivered to another apparatus; and determine (1008, 1010, 1012) whether to use the at least one transport block to scramble at least one subsequent transport block based on whether the at least one transport block has been successfully delivered to the apparatus.