Bluetooth Receiver Weak-Bit CRC Recovery Across PHY and MAC
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Solution Overview
Problem
The separation of physical layer (PHY) and medium access control (MAC) layers in Bluetooth receivers leads to decreased performance due to different stacks and system-on-chips, necessitating improved receiver performance.
Innovation Solution
Sharing information about weak-bit locations between PHY and MAC layers, allowing the MAC layer to flip weak-bits and perform multiple CRC checks on modified bit streams to enhance reception range and reduce false-positive detection rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the PHY and MAC layers are separated into different stacks and SOCs, then the device complexity is reduced and manufacturing becomes easier, but the receiver performance deteriorates due to limited error management capability
Solution Approach 1:
The patent merges the error correction functionality into the MAC layer by enabling it to flip bits in the bit stream based on weak-bit information from the PHY layer. This integration allows the MAC layer to actively participate in error correction, compensating for the separation of PHY and MAC layers into different stacks and SOCs, thereby maintaining receiver performance while preserving manufacturing advantages.
Solution Approach 2:
The patent introduces an intermediary mechanism where the PHY layer provides weak-bit information to the MAC layer, which then uses this information to make informed decisions about bit flipping. This intermediary information exchange enables coordinated error correction across the separated layers without requiring full integration of the stacks and SOCs.
2Reliability
If the MAC layer flips bits to correct errors, then the bit error rate is reduced and performance is improved, but the device complexity increases due to additional processing requirements
Solution Approach 1:
The patent applies preliminary action by having the PHY layer identify and report weak-bits before the MAC layer performs bit flipping. This pre-processing of error identification reduces the complexity of the MAC layer's error correction task, as it only needs to flip bits at previously identified weak positions rather than performing comprehensive error analysis.
Solution Approach 2:
The patent applies local quality by focusing error correction efforts only on specific weak-bits identified by the PHY layer rather than processing the entire bit stream uniformly. This localized approach reduces the overall processing complexity while maintaining high reliability at the most vulnerable positions.
3Reliability
If iterative processing is performed to generate modified bit streams, then the packet error rate is reduced and receive range is extended, but the processing time increases
Solution Approach 1:
The patent applies partial action by performing iterative processing only when necessary - specifically when the initial bit stream fails CRC validation. The MAC layer generates modified bit streams by flipping weak-bits and re-validates, repeating this process only as needed to achieve successful packet reception. This avoids unnecessary iterative processing for already correct packets, reducing average processing time while maintaining low packet error rates.
Data Source
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AI summary
A Bluetooth receiver is provided. The Bluetooth receiver comprises interface circuitry configured to receive a receive packet. Further, the Bluetooth receiver comprises physical layer processing circuitry configured to demodulate the receive packet into a bit stream representing a sequence of data symbols. Further, the physical layer configured to determine a number of bits in the bit stream having a highest likelihood of being erroneous as weak-bits and determine locations of the identified weak-bits in the bit stream. The Bluetooth receiver further comprises medium access control layer processing circuitry configured to receive the bit stream and information about the determined locations of the identified weak-bits from the physical layer processing circuitry. Further, the medium access control layer is configured to flip one of the weak-bits and a sequential bit in the bit stream in order to generate a modified bit stream, run a respective cyclic redundancy check on the bit stream and the modified bit stream and compare results of the cyclic redundancy checks on the bit stream and on the modified bit stream.