Variable Dummy Sequence Insertion for OFDM Spectrum Leakage
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Solution Overview
Problem
High-frequency wireless communication systems face increased resource overhead and spectrum leakage due to the use of Cyclic Prefix (CP) in OFDM technology, which also limits spectral efficiency and channel estimation accuracy.
Innovation Solution
The method involves inserting dummy sequences of varying lengths into data blocks, allowing for dynamic adjustment based on channel status to reduce resource overhead and suppress out-of-band leakage, while maintaining low Peak Average Power Ratio (PAPR) and high channel estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Cyclic Prefix (CP) is used in OFDM technology to resist multipath delay, then channel estimation accuracy is improved, but resource overhead increases and spectral efficiency decreases
Solution Approach 1:
The patent changes the parameter of guard interval length from fixed to variable. By dynamically adjusting the guard interval length based on channel conditions (e.g., multipath delay characteristics), the system can optimize between channel estimation accuracy and spectral efficiency. When multipath delay is significant, a longer guard interval is used; when the channel is simpler, a shorter guard interval suffices, thereby reducing overhead.
Solution Approach 2:
The patent introduces dynamic adjustment capability to the guard interval configuration. Instead of using a static fixed guard interval, the system can adaptively modify the guard interval length in response to changing channel conditions, enabling the system to balance between providing sufficient channel estimation accuracy and minimizing resource overhead according to actual deployment scenarios.
2Reliability
If fixed guard interval is used in Single Carrier technology, then channel estimation and time/frequency tracking are enabled, but spectral efficiency decreases due to inability to adapt to channel changes
Solution Approach 1:
The patent applies dynamic adjustment to the guard interval length in Single Carrier technology. By making the guard interval variable rather than fixed, the system can adapt to different channel conditions and multipath delay characteristics, thereby maintaining reliable channel estimation and time/frequency tracking while improving spectral efficiency through reduced overhead when conditions permit.
3Ease of manufacture
If CP-OFDM is used to divide frequency selective channel into parallel flat fading channels, then channel estimation method is simplified, but spectrum leakage and peak-to-average ratio increase in high frequency ranges
Solution Approach 1:
The patent changes the parameter of guard interval length to reduce spectrum leakage. By extending the guard interval length, the system can better contain the main lobe of the transmitted signal and reduce energy spillage into adjacent frequency bands. This parameter adjustment directly addresses the spectrum leakage issue while preserving the simplified channel estimation capability provided by the frequency-domain processing approach.
Data Source
AI summary
A method and apparatus for inserting dummy sequences during data modulation in a communication system, according to channel status, link status, and the like, is disclosed. In one embodiment, a method for data modulation by a wireless communication node of a wireless communication system, includes: inserting at least one first dummy sequence to a first data sequence in a first data block; and inserting at least one second dummy sequence to a second data sequence in a second data block; wherein a first length of a first dummy sequence is different from a second length of a second dummy sequence, and wherein the second dummy sequence includes the first dummy sequence or is included in the first dummy sequence.