Zero-Correlation-Zone Sequences for Wireless PHY Detection
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Solution Overview
Problem
The existing training sequences in IEEE 802.11ad specifications are not efficient for detecting the physical layer (PHY) type in wireless communication systems, as they have non-zero cross-correlations beyond a single lag, which degrades channel estimation and signal detection performance, especially in channels with multiple delayed taps.
Innovation Solution
The use of Zero-Correlation-Zone (ZCZ) Concatenated Complementary Pair (CCP) sequences with a zero correlation zone greater than one, which are designed to have zero auto-correlation for a wider range of time lags and zero cross-correlation between sequences, improving channel estimation and PHY type detection by modifying the channel estimation field (CEF) to include sequences with these properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing IEEE 802.11ad training sequences are used, then channel estimation can be performed, but cross-correlation is non-zero beyond single lag which degrades detection performance
Solution Approach 1:
The patent changes the correlation properties of training sequences by using ZCZ CCP sequences with zero auto-correlation for lags in range [-N1, N1] and zero cross-correlation for lags in range [-N2, N2], where N1 and N2 are greater than 0. This parameter change in sequence design resolves the contradiction by eliminating non-zero cross-correlations that degrade detection performance while maintaining channel estimation capability.
Solution Approach 2:
The patent employs composite sequence structures by concatenating multiple complementary sequences to form ZCZ CCP sequences. This composite approach combines the properties of individual complementary sequences to achieve extended zero-correlation zones, simultaneously improving both detection precision and estimation reliability.
2Productivity
If training sequences with narrow zero-correlation zone are used, then sequence length is reduced, but detection performance degrades in multipath channels
Solution Approach 1:
The patent extends the zero-correlation zone from a single lag to a broader range [-N2, N2] by using concatenated complementary sequences. This dimensional extension in the lag domain allows the sequence to maintain orthogonality properties over a wider range, improving detection accuracy in multipath channels without sacrificing transmission efficiency.
Data Source
AI summary
The present disclosure provides for the construction and use of a set of Zero-Correlation-Zone (ZCZ) Concatenated Complementary Pair (CCP) sequences with zero-correlation-zone range greater than one or with zero-correlation-zone range equal to one and the sequence set size greater than two. Complementary pair sequences A and B are selected and, for each member of the set of ZCZ CCP sequences, sign sequences pA and pB are combined with the complementary pair sequences to form a member ZCZ CCP sequence of the set. A ZCZ CCP sequence modified by propagation over a communication channel may be identified by cross-correlation with ZCZ CCP sequences of the set. A set of sign sequences may be constructed by recursive expansion from an initial set or found by a computer search. The sequences may be used in a transceiver of a portable electronic device or other communication device.