Random Access Signal Cyclic Shifts for Doppler-Resistant Capacity
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Solution Overview
Problem
The Zadoff-Chu (ZC) sequence's orthogonality is affected by Doppler shifts, limiting its sequence capacity and communication performance in wireless cellular mobile communication systems.
Innovation Solution
Implementing a cyclic shift sequence that includes both delay domain and Doppler domain shifts on a quadratic exponential sequence, increasing the sequence capacity by forming zero and low ambiguity zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclic shift is restricted to resist frequency offset, then frequency offset resistance is improved, but sequence capacity is limited
Solution Approach 1:
The patent transitions from one-dimensional cyclic shift (time domain only) to two-dimensional cyclic shift by introducing both delay domain cyclic shift and Doppler domain cyclic shift. This dimensional expansion allows the system to simultaneously achieve frequency offset resistance and increased sequence capacity by operating in an extended parameter space.
Solution Approach 2:
The patent changes the parameters of cyclic shift by defining a two-dimensional cyclic shift sequence with independent delay domain and Doppler domain components. This parameter transformation enables the generation of more diverse sequences while maintaining orthogonality and resistance to frequency offset through controlled manipulation of shift parameters.
2Ease of operation
If ZC sequence is used for random access, then initial network access is enabled, but sequence capacity is limited affecting communication performance
Solution Approach 1:
The patent segments the cyclic shift operation into two independent components: delay domain cyclic shift and Doppler domain cyclic shift. This segmentation allows each component to be optimized independently, with the delay domain handling timing aspects and the Doppler domain handling frequency aspects, thereby increasing the total number of available sequences for random access.
Data Source
AI summary
A communication method may include a first apparatus that obtains a cyclic shift sequence, where the cyclic shift sequence includes a delay domain cyclic shift and a Doppler cyclic shift; and outputs the cyclic shift sequence, where the cyclic shift sequence is used to generate a random access signal or a sensing signal.