DSDS Integrity Protection via Payload Validation
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Solution Overview
Problem
Dual subscriber identity module (SIM) dual standby (DSDS) devices face integrity failures due to frequent radio resource control (RRC) signal misses and sequence number wrap-around issues, leading to degraded quality of service, as conventional systems are inadequate in handling more than one cycle of RRC signal misses.
Innovation Solution
The proposed solution involves a method for providing integrity protection in DSDS devices by validating messages after a tune-away procedure, checking payload matching instead of relying solely on message sequence numbers, and performing two levels of integrity validation with and without incrementing the hyper frame number to handle sequence number wrap-around scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single RF antenna is multiplexed between two SIM stacks in a DSDS device, then device complexity is reduced and ease of operation is improved, but reliability deteriorates due to frequent RRC signal misses and integrity failures
Solution Approach 1:
The patent applies preliminary action by storing the last received message before the RF antenna is tuned away to the second SIM stack. This allows the system to detect duplicate messages and handle wrap-around cases when the antenna returns to the first SIM stack, preventing integrity failures without requiring complex continuous monitoring mechanisms.
Solution Approach 2:
The patent implements feedback by comparing the payload of the currently received message with the stored last received message. When the message sequence numbers match but the payloads differ, the system identifies wrap-around cases and adjusts the hyper frame number accordingly, ensuring reliable integrity protection despite the shared RF antenna.
2Device complexity
If conventional wrap-around detection is used, then handling of minor signaling misses is simplified, but reliability deteriorates when more than one cycle of RRC SN is missed
Solution Approach 1:
The patent stores the last received message in advance before the RF antenna is tuned away. This preliminary storage enables the system to detect wrap-around cases when the antenna returns, even when more than one cycle of RRC SN is missed, without requiring complex detection mechanisms.
Solution Approach 2:
The patent changes the approach from relying solely on message sequence numbers to comparing both sequence numbers and payloads. When the sequence numbers match but payloads differ, the system identifies wrap-around cases and adjusts the hyper frame number, ensuring reliable integrity validation beyond the limitations of conventional methods.
3Device complexity
If RRC SN wrap-around is handled by incrementing HFN, then message validation is simplified, but reliability deteriorates when the receiver uses previous HFN
Solution Approach 1:
The patent uses feedback by comparing the payload of the currently received message with the stored last received message. When sequence numbers match but payloads differ, the system identifies wrap-around cases and adjusts the hyper frame number accordingly, ensuring reliable validation even when the receiver uses previous HFN values.
Solution Approach 2:
The patent changes the validation approach by incorporating payload comparison into the integrity validation process. This allows the system to detect wrap-around cases and adjust HFN dynamically, ensuring reliable message validation beyond the simplified conventional approach.
Data Source
AI summary
Methods and apparatuses are provided for providing integrity protection in a dual subscriber identity module (SIM) dual standby (DSDS) device. A first message is received on a first SIM of the DSDS device before a radio resource of the DSDS device is tuned away from the first SIM to a second SIM by performing a tune-away procedure. A second message is received after completion of the tune-away procedure. The second message is validated. It is determined whether a first payload of the first message matches a second payload of the second message, when the first message and the second message have a same message sequence number. It is determined that the second message is a duplicate message, when the first payload matches the second payload.