Zadoff-Chu Sequence Frequency Offset Estimation in M2M Systems
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Solution Overview
Problem
Existing carrier frequency offset estimation methods in machine-to-machine (M2M) communication systems have an inaccurate frequency offset estimation due to a small estimation range, which is exacerbated by high mobility and low power consumption requirements.
Innovation Solution
The use of a Zadoff-Chu (ZC) sequence with specific parameters for synchronization, allowing for expanded estimation range and improved accuracy of frequency offset estimation by the receive end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a narrowband system is used to reduce power consumption, then power consumption is reduced, but the estimation range of carrier frequency offset estimation method becomes small
Solution Approach 1:
The patent changes the parameter of the synchronization sequence from conventional sequences to Zadoff-Chu sequences with specific root indices. This parameter change enables the system to maintain accurate frequency offset estimation over a wider range while operating in narrowband conditions, thus resolving the contradiction between reduced power consumption and maintained estimation range.
2Device complexity
If existing carrier frequency offset estimation method is used, then the method is simple, but the frequency offset estimation value is inaccurate when estimation range is exceeded
Solution Approach 1:
The patent employs Zadoff-Chu sequences with specifically selected root indices as synchronization sequences. This parameter change in the sequence design enables the estimation method to maintain both simplicity and high accuracy even when the estimation range is exceeded, resolving the contradiction between method simplicity and estimation accuracy.
3Ease of manufacture
If crystal oscillator with low cost is used in M2M applications, then cost is reduced, but system carrier frequency offset becomes high
Solution Approach 1:
The patent converts the harmful effect of high carrier frequency offset caused by low-cost crystal oscillators into a beneficial situation. By using Zadoff-Chu sequences with specific root indices as synchronization sequences, the system can accurately estimate and compensate for the frequency offset, thereby transforming the disadvantage of cost reduction into an acceptable performance level.
4Reliability
If Doppler frequency shift compensation is needed in high mobility scenario, then communication reliability is improved, but existing estimation method becomes inadequate
Solution Approach 1:
The patent uses Zadoff-Chu sequences with specifically designed root indices that provide robust frequency offset estimation capability under Doppler frequency shift conditions. This parameter change in the synchronization sequence enables reliable communication in high mobility scenarios by maintaining accurate frequency offset estimation despite the inadequacy of existing estimation methods.
Data Source
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AI summary
The present invention provides a synchronization signal receiving method, including: receiving, by a receive end, a synchronization sequence sent by a transmit end, where the synchronization sequence includes a carrier frequency synchronization sequence, the carrier frequency synchronization sequence is zc(m)=e±jπm(m+1+2q)/L, m = 0,1,...,L - 1, q ∈ Z, L indicates a length of the carrier frequency synchronization sequence, q indicates a parameter of the carrier frequency synchronization sequence, Z indicates an integer set, e±jπm(m+1+2q)/L indicates the (±jπm(m+1+2q)/L)th power of e, and e is a natural constant; and performing, by the receive end, frequency offset estimation according to the received synchronization sequence, to obtain a frequency offset estimation value. With the technical solutions of embodiments of the present invention, accuracy of frequency offset estimation can be improved.