BR/EDR Link MIC Recovery Using SEQN-Based Retransmission Detection
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Solution Overview
Problem
In noisy or poor RF environments, BR/EDR links in wireless personal area networks (WPANs) become unreliable due to transmission errors, leading to link loss as the receiving device continually detects errors and transmits negative acknowledgments, which existing error correction techniques fail to adequately address.
Innovation Solution
A two-stage re-transmission detection using sequence bits and message integrity check (MIC) is employed to identify and correct errors, ensuring synchronization of packet counters and maintaining communication links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error correction techniques are used to detect and correct transmission errors, then reliability is improved, but device complexity increases
Solution Approach 1:
The error correction process is divided into two distinct stages: first detecting errors using sequence bits and MIC, then correcting errors through targeted retransmission. This segmentation allows the system to handle errors systematically without implementing overly complex comprehensive error correction mechanisms.
Solution Approach 2:
The system uses feedback from MIC failures and sequence bit mismatches to trigger corrective actions. When errors are detected, the receiving device sends feedback signals to request retransmission, creating a closed-loop error correction system that improves reliability without requiring complex error prediction or prevention mechanisms.
2Measurement precision
If repeated negative acknowledgments are transmitted to indicate transmission errors, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system performs preliminary error detection using sequence bits and MIC before initiating the retransmission process. By detecting and identifying errors in advance, the system can prepare appropriate corrective actions and reduce the time spent on repeated unnecessary retransmissions.
Solution Approach 2:
Instead of continuously repeating NACKs, the system creates a corrected copy of the data packet by requesting retransmission only when necessary. This reduces the time loss associated with repeated error indications while maintaining accurate error detection through the copied and verified data.
3Reliability
If sequence bits are used for error detection, then reliability is improved, but device complexity increases
Solution Approach 1:
The sequence bits serve multiple functions: they detect transmission errors, identify packet retransmissions, and synchronize communication between devices. This multi-functionality improves reliability without proportionally increasing complexity, as a single mechanism achieves multiple objectives.
Solution Approach 2:
The system merges the error detection function with the packet identification function by using sequence bits that are part of the standard packet structure. This integration allows reliable error detection without adding separate complex detection mechanisms.
4Reliability
If message integrity check is performed on received packets, then reliability is improved, but loss of time increases
Solution Approach 1:
The system performs MIC verification selectively rather than on every packet unconditionally. By applying partial verification based on detected errors and transmission conditions, the system maintains data integrity while reducing the time overhead of excessive verification operations.
Data Source
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AI summary
Apparatus, methods, and computer-readable media for an error correction technique that identifies transmission errors and corrective actions to maintain a link are disclosed herein. An example method of wireless communications includes receiving a first PDU comprising at least one of a SEQN bit or a packet counter value. The example method includes determining whether a value of the SEQN bit of the received first PDU is an expected SEQN or an unexpected SEQN. The example method includes calculating a MIC of the received first PDU. The example method includes determining whether the received first PDU is a re-transmission of a previous PDU or the received first PDU comprising errors. The example method includes transmitting an ACK or a NACK in response to the determination of whether the first PDU is the re-transmission of the previous PDU or the first PDU comprising errors.