DMRS Cyclic Shift Resource Selection for V2X Interference
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Solution Overview
Problem
Current D2D communication technologies, as standardized in 3GPP Rel-12, face challenges in supporting high-speed V2X communications due to inter-subcarrier interferences, in-band leakage interference, and resource conflicts, which affect reception reliability and delay sensitivity, especially at high speeds and frequencies above 6 GHz.
Innovation Solution
A method for transmitting data that involves sensing and selecting resources based on the received power and total energy of other devices, using multiple DMRS sequences and energy-based resource selection to improve channel estimation and reduce interference, allowing for better resource allocation and interference avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If D2D communication is used in V2X systems at high speeds and frequencies above 6 GHz, then direct communication between devices is enabled, but inter-subcarrier interferences and in-band leakage interference occur affecting reception reliability
Solution Approach 1:
The patent changes the parameter of DMRS sequence by introducing multiple sequences with different cyclic shifts. This allows the receiving device to select an appropriate sequence for channel estimation, thereby improving reception reliability in high-speed V2X scenarios where inter-subcarrier interference occurs
Solution Approach 2:
The receiving device measures received power and provides feedback about channel conditions. This feedback mechanism enables the system to adapt to high-speed communication conditions by selecting appropriate resources and DMRS sequences, improving reception reliability
2Productivity
If energy-based resource selection is implemented, then resource allocation efficiency is improved, but measurement accuracy of received power is affected by interference
Solution Approach 1:
The patent applies different DMRS sequences with different cyclic shifts to different subcarriers or resource elements. This local differentiation allows the receiving device to perform accurate channel estimation and received power measurement even in the presence of interference, maintaining measurement precision while enabling efficient energy-based resource selection
Solution Approach 2:
The DMRS sequence acts as an intermediary that facilitates accurate received power measurement. By using multiple DMRS sequences with different cyclic shifts, the system can isolate and measure the desired signal power separately from interfering signals, enabling accurate measurement for energy-based resource selection
3Measurement precision
If multiple DMRS sequences with different cyclic shifts are used, then channel estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the DMRS sequence into multiple versions with different cyclic shifts. This segmentation allows the receiving device to process only the necessary sequences for channel estimation rather than handling all possible sequences, reducing computational complexity while maintaining estimation accuracy
Solution Approach 2:
The patent changes the cyclic shift parameter of the DMRS sequence to create multiple distinguishable sequences. This parameter-based differentiation enables accurate channel estimation through simple correlation operations, avoiding the need for complex processing while improving estimation accuracy in high-speed V2X scenarios
4Reliability
If sensing and resource selection based on received power is performed, then resource conflicts are reduced, but decoding performance requires higher accuracy
Solution Approach 1:
The patent changes the DMRS sequence parameter (cyclic shift) to improve channel estimation accuracy. This enhanced estimation accuracy directly improves decoding performance, enabling reliable resource selection and conflict avoidance in V2X communications
Solution Approach 2:
The system uses feedback from received power measurement and channel estimation to make informed resource selection decisions. This feedback loop ensures that resources are selected based on accurate measurements, reducing resource conflicts while maintaining decoding accuracy
Data Source
AI summary
A first device senses scheduling assignment (SA) and received power of a second device, and a total received energy of each subband. The first device determines a reference value of received power of the second device and a reference value of total received energy, based on a sensing result of the second device. The first device selects a resource, based on the reference value of received power and reference value of total received energy, the first device transmits data. By adopting the method of the present disclosure, decoding performance of SA is improved, and accuracy for measuring received power of the SA is also enhanced. Subsequently, on the basis of SA and received power, performances for selecting/re-selecting channel resources are improved.