D2D Synchronization Signal Detection Using Distinct Zadoff-Chu Root Index Sets
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Solution Overview
Problem
Current wireless communication systems face challenges in performing device-to-device (D2D) synchronization, particularly in distinguishing between in-coverage and out-of-coverage D2D synchronization sources, which affects efficient D2D communication.
Innovation Solution
A method for a user equipment (UE) supporting D2D communication that detects synchronization signals using a first index set for network-transmitted signals and a second index set for D2D synchronization sources, with the second set having one fewer root index than the first, allowing differentiation between in-coverage and out-of-coverage sources through specific root index configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the same root indexes are used for both network synchronization signals and D2D synchronization signals, then the detection process becomes simpler, but it becomes impossible to distinguish between in-coverage and out-of-coverage D2D synchronization sources
Solution Approach 1:
The patent applies local quality by assigning different root index sets to different synchronization scenarios: the first index set (with root indexes 25, 29, 34) is used for network synchronization signals, while the second index set (with root indexes 25, 29) is used for D2D synchronization signals. This local differentiation allows the system to maintain simple detection procedures within each context while enabling coverage status identification through the distinction between the two index sets.
Solution Approach 2:
The patent changes the parameter of root index configuration based on the synchronization context. By modifying the root index set from the first index set (3 root indexes) to the second index set (2 root indexes) when detecting D2D synchronization signals, the system encodes coverage status information in the parameter selection itself, allowing UEs to determine whether they are in-coverage or out-of-coverage based on which root indexes are available for correlation.
2Loss of information
If different index sets are used for network and D2D synchronization signals, then coverage status can be identified, but the detection complexity increases
Solution Approach 1:
The patent segments the root index space into two distinct sets: the first index set containing root indexes {25, 29, 34} for network synchronization, and the second index set containing root indexes {25, 29} for D2D synchronization. This segmentation allows the UE to perform separate, optimized correlation operations for each type of synchronization signal, reducing overall detection complexity compared to handling all possibilities in a single unified process.
3Adaptability or versatility
If all root indexes from the first index set are used for D2D synchronization, then maximum flexibility is achieved, but correlation calculation complexity increases
Solution Approach 1:
The patent extracts only the necessary root indexes from the first index set for use in the second index set. Specifically, root indexes 25 and 29 are extracted and reused for D2D synchronization, while root index 34 is excluded. This extraction reduces the number of correlation calculations required for D2D synchronization from 3 to 2, lowering computational complexity while maintaining sufficient flexibility for both in-coverage and out-of-coverage scenarios.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient D2D synchronization by accurately identifying in-coverage and out-of-coverage D2D synchronization sources, improving communication efficiency and reducing complexity in correlation calculations.
Implementation Method 1
detecting a first synchronization signal transmitted from a network based on a first index set having a plurality of root indexes for a Zadoff-Chu sequence; and detecting a second synchronization signal transmitted from a D2D synchronization source based on a second index set having a plurality of root indexes which are different from the plurality of root indexes of the first index set
Data Source
Figure 1(a)~1(b)
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AI summary
A method for a device to device (D2D) communication-supporting user equipment detecting a synchronization signal, according to one embodiment of the present invention, comprises the steps of: on the basis of a first index set having a plurality of root indexes on a Zadoff-Chu sequence, detecting a first synchronization signal transmitted by a network; and, on the basis of a second index set having a plurality of root indexes that are different from the first index set, detecting a second synchronization signal transmitted by a D2D synchronization source, wherein the total number of the root indexes of the second index set is configured to be the total number of the root indexes of the first index set -1.