DMRS Truncation for PAPR Reduction in Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently generating and transmitting reference signals, particularly in Direct-to-Device (D2D) communication, where peak-to-average power ratio (PAPR) management is crucial to ensure effective data transmission and reception, especially when the receiving user equipment is not aware of the exact bandwidth used by the transmitting device.
Innovation Solution
A method is proposed where a UE generates a sequence corresponding to a basic bandwidth and maps it to a frequency band to create a demodulation reference signal (DMRS) for the full bandwidth, allowing for efficient transmission and reception by truncating the DMRS to match the data bandwidth, thereby managing PAPR and ensuring accurate signal correlation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a UE generates and transmits a reference signal covering the full bandwidth, then the receiving UE can accurately estimate the channel across the entire bandwidth, but the peak-to-average power ratio (PAPR) increases
Solution Approach 1:
The reference signal generation process is segmented into two stages: first generating a full-bandwidth reference signal for channel estimation, then truncating it to the actual data bandwidth for transmission. This segmentation allows the receiving UE to perform correlation over the full bandwidth for accurate channel estimation while the transmitting UE only transmits over the necessary data bandwidth, avoiding the PAPR increase that would result from transmitting a full-bandwidth reference signal.
Solution Approach 2:
The receiving UE performs preliminary channel estimation by correlating the received signal with a full-bandwidth reference signal sequence before knowing the exact data bandwidth. This preliminary action allows the receiver to prepare channel estimates across the entire bandwidth, then use only the relevant portion for demodulation, ensuring accurate channel knowledge is available regardless of the actual data bandwidth used.
2Object-generated harmful factors
If a UE truncates the demodulation reference signal to match the data bandwidth, then the PAPR is reduced, but the receiving UE must accurately know the data bandwidth to perform correlation
Solution Approach 1:
The receiving UE performs preliminary correlation operations using the full-bandwidth reference signal sequence before the exact data bandwidth is determined. This preliminary action ensures that channel estimation is established across the entire bandwidth, and the receiver can then identify the actual data bandwidth and use the corresponding portion of the channel estimates for demodulation, eliminating the need for explicit bandwidth signaling.
3Measurement precision
If the receiving UE performs correlation over the full bandwidth, then accurate channel estimation is achieved, but computational complexity increases
Solution Approach 1:
The correlation computation is segmented into a preliminary full-bandwidth correlation stage followed by a selective usage stage. The receiving UE performs correlation over the full bandwidth to establish accurate channel estimates, then segments the bandwidth based on the actual data transmission and uses only the necessary portion for demodulation. This segmentation reduces computational complexity compared to continuously processing the full bandwidth while maintaining estimation accuracy.
Data Source
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AI summary
One embodiment of the present invention relates to a method for a terminal generating and transmitting a reference signal and data in a wireless communication system, comprising the steps of: generating a sequence corresponding to a basic bandwidth; generating a demodulation reference signal (DMRS) corresponding to the entire bandwidth by mapping the generated sequence onto a frequency band; truncating the generated DMRS according to the bandwidth of data to be transmitted; and transmitting the truncated DMRS and the data.