Uplink Fast Feedback Transmission Using Non-Coherent Modulation
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Solution Overview
Problem
In OFDMA communication systems, the existing methods for transmitting uplink fast feedback information face challenges such as increased error rates and reduced operation stability due to insufficient frequency-time resources, and lack of flexibility in transmitting accurate control information, particularly with 4-bit information transmission.
Innovation Solution
The use of a non-coherent modulation scheme combined with an M-ary channel code to efficiently transmit 5-bit or 6-bit uplink fast feedback information, optimizing performance by reducing the need for pilot tones and increasing the number of codewords, thereby enhancing accuracy and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional binary channel encoding with coherent modulation is used for uplink fast feedback transmission, then the transmission method is simple, but the error rate increases and operation stability decreases due to insufficient frequency-time resources
Solution Approach 1:
The patent changes the fundamental parameters of the transmission system by switching from binary channel encoding to M-ary channel encoding (where M≥2), and from coherent modulation to non-coherent orthogonal modulation. This parameter change enables more efficient use of limited frequency-time resources, reducing the error rate while maintaining transmission simplicity.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the system to flexibly select from multiple pre-defined codeword sets corresponding to different modulation patterns. This dynamic selection capability enables the system to adapt to varying channel conditions and resource constraints, improving operation stability without increasing complexity.
2Loss of information
If 4-bit information transmission is used, then the transmission overhead is reduced, but the flexibility and accuracy of control information transmission are insufficient
Solution Approach 1:
The patent extends the information transmission capacity by transitioning from 4-bit to 5-bit or 6-bit transmission through M-ary encoding. This dimensional expansion in the information space allows more feedback information to be conveyed within the same resource constraints, improving accuracy while maintaining acceptable overhead levels.
Solution Approach 2:
The patent segments the feedback information into multiple bits (5 or 6 bits) that can be independently encoded and transmitted using different codewords from predefined sets. This segmentation allows flexible combination and selection of information elements, enhancing adaptability without significantly increasing overall overhead.
3Reliability
If more frequency-time resources are allocated to uplink fast feedback channel, then transmission reliability improves, but the overhead rate increases
Solution Approach 1:
The patent changes the encoding efficiency parameter by using M-ary channel encoding instead of binary encoding. This parameter change allows more information to be packed into the same number of transmitted symbols, improving reliability without requiring additional frequency-time resources, thus maintaining low overhead rate.
Solution Approach 2:
The patent combines multiple functions into the uplink fast feedback channel by using non-coherent orthogonal modulation that can convey both channel quality information and other feedback data efficiently. This merging allows reliable transmission of comprehensive feedback information within limited resources, avoiding the need for separate dedicated channels.
Data Source
AI summary
An apparatus and method for transmitting uplink fast feedback information using a fast feedback channel in an orthogonal frequency division multiple access (OFDMA) communication system. A channel encoder selects information data for uplink fast feedback information, and determines a codeword from a pre-determined codeword set corresponding to the selected information data. A non-coherent modulator chooses transmission symbols by performing orthogonal modulation according to the determined codeword based on a predetermined modulation pattern, and maps the chosen symbols into sub-carriers. An inverse fast Fourier transform (IFFT) block performs an inverse fast Fourier transform (IFFT) on the mapped symbols and transmits the IFFT processed mapped symbols.