Repeated Coded Waveform Transmission for Low-SNR Small Payloads
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Solution Overview
Problem
Current 5G NR mobile communication systems face challenges in transmitting small payloads with low error probability at very low signal-to-noise ratios, particularly due to sub-optimal decoding algorithms and interference in existing control channel formats like PUCCH, which require complex filtering and increased receiver complexity.
Innovation Solution
A transmitter device that generates a transmission waveform in N dimensions from payload bits, combines it with an outer code sequence across multiple time slots, and transmits the combined signal using multiple antennas, optimizing error probability by choosing B1 and B2 bits to minimize overall errors, and using non-coherent codes or Hadamard matrices for improved detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If peak windowing, scaling, and clipping are used to reduce PAPR, then PAPR is reduced, but interference and distortions are generated in the OFDM modulated signal requiring further filtering
Solution Approach 1:
The patent extracts the harmful peaks from the OFDM signal through clipping, then processes them separately through an adaptive filtering stage to remove the introduced distortions while preserving the low-PAPR characteristics
Solution Approach 2:
An adaptive filter is introduced as an intermediary component between the clipping stage and the output, which compensates for the distortions caused by clipping while maintaining the reduced PAPR benefits
2Device complexity
If sub-optimal reduced-complexity decoding algorithms are used, then receiver complexity is reduced, but detection accuracy deteriorates
Solution Approach 1:
The decoding process is segmented into two stages: first using reduced-complexity algorithms for initial detection, then applying a more sophisticated maximum likelihood decoder to refine the detection accuracy, thereby distributing the computational burden while maintaining high accuracy
Solution Approach 2:
The reduced-complexity algorithm performs preliminary detection to identify candidate solutions, which then guides the more accurate maximum likelihood decoder, reducing its search space and improving overall detection accuracy
3Ease of operation
If fully non-coherent receiver is used, then decoding can be performed without channel estimation, but receiver complexity increases especially for RM coded case with longer bit lengths
Solution Approach 1:
The receiver architecture is segmented into coherent and non-coherent processing paths, allowing the system to use simple non-coherent detection for initial processing while maintaining the option for more complex channel estimation-based processing when needed
Data Source
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AI summary
There is provided a transmitter device (1) for transmitting a digital input message corresponding to payload data through a communication channel (3), the payload data comprising B1 payload bits, the transmitter device comprising: - a waveform generator (10) configured to determine a transmission waveform in N dimensions from said B1 payload bits, the transmission waveform being represented by a signal vector s comprising L components sl(m); - an outer code generator (11) configured to generate an outer code xn from additional B2 bits, the outer code being represented by a vector xn comprising Nreps components; - a repetition unit (12) configured to spread the information contained in the waveform s across Nreps time slots; - a combining unit (14) configured to combine said waveform s with the outer code sequence xn, which provides a combined signal xnsl, the components of the outer code xn modulate the waveform coming from at least a part of a time slot; the transmitter device being configured to transmit the combined signal in a particular repetition n over the communication channel using the transmit antennas.