Non-repetitive Reference Signal Sequences for OFDM PAPR Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communication systems, particularly OFDM systems, face high Peak-to-Average Power Ratio (PAPR) issues due to repeated reference signal sequences, leading to increased Signal-to-Quantization Noise Ratio (SQNR) and reduced power amplifier efficiency, which are not effectively mitigated by existing solutions like power backoff and clipping.
Innovation Solution
Generating non-repetitive reference signal sequences based on resource element indexes or code division multiplexing groups to avoid repetition, thereby reducing PAPR by ensuring that each sequence is unique across different ports and resource blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If repeated reference signal sequences are used in OFDM systems, then channel estimation and demodulation are simplified, but PAPR increases leading to reduced power amplifier efficiency and increased SQNR
Solution Approach 1:
The patent applies local quality by making reference signal sequences port-specific and non-repetitive only where needed (in resource blocks assigned to specific ports), while maintaining standard repetitive structures in other regions. This localized modification reduces PAPR in critical areas without unnecessarily complicating the overall reference signal structure.
Solution Approach 2:
The patent changes the parameter of reference signal sequence generation by introducing port-index-dependent variations. Instead of using identical repetitive sequences across all ports, the system modifies sequence parameters (such as initialization values or scrambling codes) based on port index, which reduces peak values while maintaining the reference signal's essential function for channel estimation.
2Reliability
If power backoff is applied to mitigate high PAPR, then PAPR impact on power amplifier is reduced, but coverage and power amplifier efficiency are reduced
Solution Approach 1:
The patent extracts the harmful repetitive pattern from reference signal sequences and replaces it with non-repetitive port-specific sequences. By removing the repetition that causes constructive interference and high peaks, the system reduces PAPR at its source, eliminating the need for power backoff and preserving full transmission power and coverage.
3Stress or pressure
If clipping is applied to reduce PAPR, then peak values are limited, but Error Vector Magnitude increases and signal quality is distorted
Solution Approach 1:
Instead of applying clipping to cut off peak values (which distorts the signal), the patent inverts the approach by designing reference signal sequences that inherently avoid generating high peaks through non-repetitive port-specific patterns. This preventive strategy reduces PAPR before transmission without requiring aggressive peak limiting that would compromise signal quality.
4Loss of energy
If non-repetitive reference signal sequences are generated based on port index, then PAPR is reduced improving power amplifier efficiency, but sequence generation complexity increases
Solution Approach 1:
The patent implements self-service by having each port generate its own unique reference signal sequence based on its port index through standardized algorithms (such as pseudo-random sequence generators with port-specific initialization). This self-generating approach creates port-specific non-repetitive sequences without requiring complex centralized coordination or manual configuration, thus reducing PAPR while keeping implementation complexity manageable.
Data Source
AI summary
The described technology is generally directed towards having a transmitter in a wireless network generate and map reference signal sequences (e.g., for demodulation or other reference signal usage) so that the reference signal sequences are non-repetitive in a resource block. Avoiding repetition of the reference signal sequences reduces the peak-to-average power ratio in orthogonal frequency-division multiplexing (OFDM) systems. In one aspect, a transmitter device generates different reference signal sequences to avoid repetition of resource signal sequences, and maps the different reference signal sequences to appropriate (different) resource elements of a resource block. In one implementation, the different reference signal sequences can be based on different indexes of antenna ports. In an alternative implementation, the different reference signal sequences can be based on different code division multiplexing groups.