Wireless Node Location Privacy via Coordinated Address and Sequence Changes
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Solution Overview
Problem
Wireless network nodes can be identifiable and tracked based on constant or predictable frame sequence numbers in IEEE 802.11 packet headers, even with periodic changes in access addresses and payload encryption.
Innovation Solution
Randomly changing the frame sequence number in conjunction with changing the access address, such as the MAC address, to make the node's identity less predictable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frame sequence number is incremented for each HS-DSCH data frame, then data transmission reliability is improved through duplicate detection, but location privacy is worsened as the node becomes identifiable and trackable
Solution Approach 1:
The patent applies dynamics by making the frame sequence number generation process adaptive rather than static. Instead of simply incrementing the sequence number for each frame, the system dynamically generates sequence numbers using a hash function that takes multiple inputs (data packet payload, data packet header, previous frame sequence number). This dynamic generation ensures that even if packets are captured and replayed, the sequence numbers will differ, preventing tracking while maintaining duplicate detection capability
Solution Approach 2:
The patent introduces an intermediary mechanism - a hash function - that mediates between the need for predictable sequence numbers (for reliability) and the need for unpredictable sequence numbers (for privacy). The hash function transforms multiple input parameters into a sequence number that appears random to external observers but maintains mathematical properties that allow the receiver to detect duplicates, thus serving as an intermediary that reconciles the conflicting requirements
2Object-affected harmful factors
If access address is changed periodically, then location privacy is improved, but tracking capability is worsened as third parties can still identify nodes through predictable patterns
Solution Approach 1:
The patent applies parameter changes by modifying how frame sequence numbers are generated - changing from a simple incremental parameter to a hash-based parameter that incorporates multiple inputs including payload, header, and previous sequence number. This parameter transformation makes the sequence number generation more complex but ensures that even with periodic access address changes, the combined effect creates sufficiently unpredictable packet identifiers that prevent tracking
Data Source
Figure 1A~2
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AI summary
A method including changing an access address of a network interface of a wireless network node,changing a frame sequence number of a network interface of the wireless network node in an unpredictable manner, and performing the changing of the access address and changing of the frame sequence number in a coordinated manner.