Secure UWB Channel Sounding Using Pseudo-Random Code Sets
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Solution Overview
Problem
Ultra-wideband (UWB) communication systems face vulnerabilities in channel sounding due to predictable sync sequences and periodic codes, which can lead to reduced accuracy and increased sequence length for effective channel estimation.
Innovation Solution
A method for generating pseudo-random code sets, such as Golay Complementary Sequences (GCS) and Low Auto-correlation Sum Sets (CLASS), that allow for asymmetric delays and secure channel sounding by canceling auto-correlation sidelobes, enabling efficient channel estimation without significantly reducing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If predictable sync sequences and periodic codes are used for channel sounding, then channel estimation can be performed, but security is reduced and sequence length must be increased to maintain accuracy
Solution Approach 1:
The patent transforms the channel sounding process by changing the fundamental parameter of the code sequence from predictable/periodic to pseudo-random. This parameter change enables the system to achieve both security (through unpredictability) and measurement precision (through controlled autocorrelation properties of the pseudo-random sequence), resolving the contradiction between these two requirements.
2Productivity
If predictable sync sequences are used, then channel sounding can be performed, but security vulnerabilities increase
Solution Approach 1:
The patent changes the parameter of sequence predictability from high (predictable) to low (pseudo-random), which eliminates security vulnerabilities while preserving channel sounding efficiency. The pseudo-random sequence maintains necessary correlation properties for channel estimation while being unpredictable to unauthorized users.
3Measurement precision
If periodic codes are used for channel estimation, then channel sounding can be performed, but sequence length must be increased to maintain accuracy
Solution Approach 1:
The patent changes the sequence type from periodic to pseudo-random, which alters the autocorrelation characteristics. The pseudo-random sequence provides sharp autocorrelation peaks with low sidelobes, enabling accurate channel estimation with shorter sequence lengths compared to periodic sequences that require longer lengths to achieve the same precision.
4Measurement precision
If longer sequence lengths are used to compensate for periodic code limitations, then channel estimation accuracy is maintained, but transmission time and complexity increase
Solution Approach 1:
The patent changes the sequence structure parameter from periodic to pseudo-random, which fundamentally improves the autocorrelation properties. This parameter change allows the system to achieve the same measurement precision with significantly shorter sequence lengths, thereby reducing transmission time and eliminating the time loss associated with longer periodic sequences.
Data Source
AI summary
In an ultra-wideband (“UWB”) communication system comprising a pair of UWB transceivers, methods for securely performing channel sounding. In a first GCP Sync method, a pre-determined set of Golay Complementary Pairs is added to an 802.15.4a frame. In a second CLASS method, a cyphered low auto-correlation sum set is added to frame. In a third LCSSS method, a low cross-correlation sidelobe sum set is added to the frame. In general, these methods are adapted to transmit a pseudo-randomly generated codeset which may have inherent sidelobe distortions, and then, in the receiver, to compensate for this, and any channel-induced, distortion by selectively modifing the cross-correlation codeset.