PTRS Frequency Avoidance for DC Tone Collision in Wireless
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Solution Overview
Problem
Wireless communication systems face interference issues due to collisions between phase-noise tracking reference signals (PTRS) and direct current (DC) tones, leading to inefficient reception of PTRS, which affects phase noise correction and communication efficiency.
Innovation Solution
The method involves identifying a DC tone within resource blocks and determining distinct frequencies for PTRS transmissions, allowing PTRS to be transmitted using different frequencies, thereby avoiding collisions and improving reception. This includes generating DFT-s-OFDM symbols, appending PTRS, and using scrambled modulation symbols across antenna ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PTRS are transmitted at fixed frequencies, then transmission simplicity is maintained, but collisions with DC tones occur leading to poor reception
Solution Approach 1:
The patent changes the frequency parameter of PTRS dynamically based on DC tone location. Instead of using fixed frequencies, the system identifies DC tone positions and assigns PTRS to alternative frequencies that avoid collision, thereby improving reception quality while managing complexity through standardized avoidance rules
Solution Approach 2:
The system performs preliminary identification of DC tone locations before allocating PTRS frequencies. By detecting and marking DC tone positions in advance, the system can proactively assign non-colliding frequencies to PTRS, preventing reception issues before they occur
2Adaptability or versatility
If additional reference signals are transmitted to enable sharing, then reference signal availability improves, but scheduling overhead increases significantly
Solution Approach 1:
The patent makes PTRS universally accessible to multiple receivers by designing them with receiver-independent characteristics. The same PTRS can be used by multiple UEs for phase noise compensation, eliminating the need for UE-specific reference signals and reducing scheduling overhead while maintaining adaptability
3Productivity
If PTRS frequencies are assigned without considering DC tones, then allocation simplicity is maintained, but interference with DC tones occurs reducing communication efficiency
Solution Approach 1:
The system dynamically adjusts PTRS frequency parameters based on DC tone locations. By changing the frequency assignment parameter to avoid DC tones, the system improves communication efficiency while managing complexity through established avoidance mechanisms and standardized frequency selection rules
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. In one example, phase-noise compensation tracking signals (PTRS) may be transmitted using sets of resource blocks (RBs), where a frequency for each PTRS within the sets RBs is different from a frequency corresponding to a direct current (DC) tone. In another example, a time-domain-based PTRS may be used, where a discrete Fourier transform (DFT)-spread-orthogonal frequency division multiplexing (DFT-s-OFDM) symbol may include a cyclic prefix and a PTRS inserted in the DFT-s-OFDM symbol. Additionally or alternatively, a guard-interval-based DFT-s-OFDM symbol may include a PTRS that replaces part or all of a guard interval. In some examples, subsets of tones used for PTRS across a system bandwidth may be transmitted using a scrambled modulation symbol, where at least one antenna port may be used for the transmission of PTRS.