Uplink Synchronization Timing Offset Estimation for NPRACH Preambles
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Solution Overview
Problem
Existing base stations face challenges in accurately obtaining uplink synchronization in wireless communication systems, particularly in NB-IoT systems, due to difficulties in calculating timing offsets using correlations between adjacent symbol groups in NPRACH preambles.
Innovation Solution
A method and device for a base station to obtain uplink synchronization by calculating timing offsets based on correlations between symbol groups and subcarrier differences using a combination of coherent combining, correlation value calculation, and Fast Fourier Transform (FFT) to consider non-adjacent symbol group intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If base station uses correlation between adjacent symbol groups to obtain timing offset, then the calculation process is simple, but the timing offset accuracy is insufficient
Solution Approach 1:
The patent segments the correlation calculation into two distinct parts: first calculating correlation values between adjacent symbol groups, then separately calculating correlation values between non-adjacent symbol groups. This segmentation allows the system to maintain the simplicity of adjacent group correlation while adding the accuracy benefits of non-adjacent group correlation, resolving the contradiction between calculation simplicity and timing offset accuracy.
Solution Approach 2:
The patent applies partial action by using only the necessary non-adjacent symbol group correlations to improve accuracy, rather than completely replacing the adjacent symbol group correlation method. The system performs adjacent symbol group correlation first, then supplements it with selective non-adjacent symbol group correlation, achieving improved accuracy without excessive computational complexity.
2Device complexity
If base station considers only adjacent symbol groups for correlation, then the computational complexity is low, but the synchronization accuracy deteriorates
Solution Approach 1:
The patent divides the correlation computation into segmented stages: adjacent symbol group correlation computation followed by non-adjacent symbol group correlation computation. This segmentation enables the system to manage computational complexity in controlled steps while progressively improving synchronization accuracy, rather than attempting to compute all correlations simultaneously.
Solution Approach 2:
The patent extends the correlation computation from the one-dimensional adjacent symbol group relationship to include the additional dimension of non-adjacent symbol group relationships. By adding this temporal dimension to the correlation analysis, the system improves synchronization accuracy without proportionally increasing computational complexity.
3Loss of time
If base station uses only neighboring symbol groups correlation, then the processing time is short, but the timing offset estimation accuracy is insufficient
Solution Approach 1:
The patent performs preliminary correlation calculation between adjacent symbol groups first, obtaining initial timing offset estimates quickly. Then it performs additional correlation calculations between non-adjacent symbol groups to refine and improve the timing offset estimation accuracy. This preliminary action approach ensures that the system achieves acceptable accuracy quickly while having the option to improve accuracy further if needed.
Solution Approach 2:
The patent implements partial action by performing adjacent symbol group correlation as the essential minimum required for basic synchronization, then optionally performing non-adjacent symbol group correlation to achieve higher accuracy when system conditions permit. This approach balances processing time constraints with accuracy requirements flexibly.
Data Source
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AI summary
The present disclosure relates to a 5th generation (5G) or pre-5G communication system for supporting a higher data transmission rate beyond a 4th generation (4G) communication system such as long term evolution (LTE). The present disclosure is a method carried out by a terminal in a wireless communication system. The method may comprise the steps of: receiving one or more preambles from a terminal; acquiring correlation values between a plurality of symbol groups corresponding to the one or more preambles; acquiring a timing offset value on the basis of the correlation values, and subcarrier difference information of the plurality of symbol groups; generating uplink timing information on the basis of the timing offset value; and transmitting, to the terminal, a random access response (RAR) including the uplink timing information.