Synchronization Signal Transmission PAPR Reduction
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Solution Overview
Problem
The existing wireless communication systems face challenges in managing peak-to-average power ratio (PAPR) issues during the transmission of synchronization signals in device-to-device (D2D) communication, which affects power efficiency and detection performance.
Innovation Solution
The method involves generating a secondary synchronization signal (SD2DSS) by combining sequences with specific cyclic shifts and power reduction techniques, allowing for equal transmission on contiguous symbols to reduce PAPR and improve detection complexity, while setting different transmit powers for primary and secondary synchronization signals based on their PAPR properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If synchronization signals are transmitted with high power to ensure detection performance, then detection performance is improved, but peak-to-average power ratio increases causing signal distortion
Solution Approach 1:
The synchronization signal transmission is divided into multiple contiguous symbols with different power levels. The primary synchronization signal is transmitted on the first symbol with higher power, while the secondary synchronization signal is transmitted on the second symbol with lower power. This segmentation allows each component to be optimized independently, ensuring detectability while controlling overall PAPR.
Solution Approach 2:
Different power levels are applied to different time locations (symbols) within the synchronization signal transmission. The first symbol carries the primary synchronization signal with higher transmit power for robust detection, while the second symbol carries the secondary synchronization signal with lower transmit power. This local quality differentiation resolves the contradiction by providing high power where needed without uniformly increasing PAPR across all symbols.
2Use of energy by moving object
If power reduction techniques are applied to reduce PAPR, then power efficiency is improved, but detection performance may deteriorate
Solution Approach 1:
The transmit power is dynamically adjusted based on the symbol index and signal type. The first symbol transmitting the primary synchronization signal uses higher power (first transmit power), while subsequent symbols transmitting the secondary synchronization signal use lower power (second transmit power). This dynamic power adjustment maintains detection performance for the critical primary signal while improving overall power efficiency through reduced power on secondary symbols.
3Measurement precision
If equal power is transmitted for all synchronization signal symbols, then detection performance is maintained, but PAPR increases causing inefficiency
Solution Approach 1:
The transmit power parameter is changed based on the symbol index and signal component. Instead of using a fixed power level for all synchronization signal symbols, the system transitions from a single power level to multiple power levels (first transmit power for primary signal, second transmit power for secondary signal). This parameter change optimizes the balance between detection performance and power efficiency by matching power levels to the actual requirements of each signal component.
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3~4
AI summary
An embodiment of the present invention relates to a method for transmitting a synchronization signal in a wireless communication system. The method comprises: a step of generating a secondary synchronization signal from a combination of two sequences; and a step of transmitting the synchronization signal. The manner of combination of the two sequences varies depending on the sub-frame number to which the secondary synchronization signal is transmitted, and if the generation of the secondary synchronization signal is performed by a terminal, then the sub-frame number which determines the manner of combination is considered to be the same.