Differential Data Mapping for Wireless Channel Estimation
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Solution Overview
Problem
In wireless communication, orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) technologies face challenges with high reference signal overhead and reduced channel estimation performance due to time and frequency offsets, which degrade demodulation performance, especially when supporting a large number of users.
Innovation Solution
A data processing method that eliminates the need for a reference signal and employs differential modulation and spreading, along with flexible mapping relationships between data and time-frequency resources, to reduce the impact of time and frequency offsets and improve demodulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the quantity of symbols for sending the reference signal is increased to support a large quantity of connected users, then the reference signal can support more users, but the overhead of the reference signal becomes high
Solution Approach 1:
The patent removes the reference signal from the transmission system entirely. Instead of sending reference signals for channel estimation, the system uses the actual data symbols themselves to enable channel estimation and demodulation, thereby eliminating reference signal overhead while maintaining user support capability
Solution Approach 2:
The data symbols serve multiple functions simultaneously: they carry user data information and also function as reference signals for channel estimation and demodulation. This multi-functionality eliminates the need for separate reference signals, reducing overhead while supporting multiple users
2Adaptability or versatility
If different time offsets and different frequency offsets exist in the transmission process, then the transmission can be flexible, but the orthogonality between reference signals is compromised and channel estimation performance is reduced
Solution Approach 1:
The patent converts the harmful effect of time and frequency offsets on reference signal orthogonality into a beneficial feature. By using data symbols as both data and reference signals, the system leverages the fact that adjacent data units experience similar channel conditions even with offsets, enabling effective channel estimation without requiring orthogonal reference signals
Solution Approach 2:
The patent applies local quality by using adjacent data units as reference signals for each other. Instead of requiring global orthogonality across all users, the system uses locally adjacent data symbols to estimate local channel conditions, which remains effective even with time and frequency offsets present
Data Source
AI summary
A first communication device obtains first data, and maps, based on a mapping relationship between the first data and a time-frequency resource, the first data to the time-frequency resource for transmission. The first data includes at least two differential data symbols or at least two differential spreading data symbols. The mapping relationship includes that two adjacent data units in the first data are adjacent in time domain or frequency domain on the time-frequency resource. The first communication device may flexibly select, based on different scenarios of a time offset or a frequency offset, a mapping relationship between the first data and the time-frequency resource. Based on the mapping relationship, when the time offset or the frequency offset causes a change in frequency domain channels, frequency domain channels through which the two adjacent data units in the first data pass can be close.