Incomplete Subframe Encoding via Redundancy Version Modulo
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Solution Overview
Problem
In wireless communications, devices face challenges in performing code modulation on incomplete subframes due to unknown lengths, which prevents effective data transmission in unlicensed spectra.
Innovation Solution
Generating a first and second subframe with N OFDM symbols, where the redundancy version (RV) of the first subframe is determined based on the RV of the second subframe using a modulo function, allowing for the transmission of M OFDM symbols from both subframes, ensuring reliable data transmission even if the first subframe is incomplete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a device preempts the unlicensed spectrum for data transmission, then data throughput is improved, but the subframe becomes incomplete making code modulation impossible
Solution Approach 1:
The patent segments the incomplete subframe by identifying and separating the complete OFDM symbols from the incomplete portion. The transmitting device determines the number of complete OFDM symbols in the first subframe and processes them separately, allowing code modulation to be performed on the complete symbols while handling the incomplete subframe structure.
Solution Approach 2:
The transmitting device performs preliminary determination of the number of complete OFDM symbols in the first subframe before actual data transmission. By calculating and notifying the receiving device of this number in advance through second indication information, the system prepares the complete subframe structure beforehand, enabling proper code modulation and reception processing.
2Loss of time
If the first subframe is truncated to fit available time, then transmission timing is improved, but the length becomes unknown preventing encoding
Solution Approach 1:
The patent introduces second indication information as an intermediary that carries the number of complete OFDM symbols from the transmitting device to the receiving device. This intermediary parameter enables both devices to understand and process the incomplete subframe structure without requiring complex real-time calculations, simplifying the encoding and decoding processes.
Solution Approach 2:
The system changes the parameter representation by explicitly signaling the number of complete OFDM symbols rather than requiring the receiving device to infer it from timing information alone. This parameter change from implicit timing-based determination to explicit signaling simplifies the encoding process at the transmitting device.
3Device complexity
If complete subframes are used for transmission, then encoding is simplified, but transmission efficiency in preempted spectrum decreases
Solution Approach 1:
The patent makes the subframe structure dynamic by allowing the number of complete OFDM symbols to vary based on channel conditions and preemption timing. The system adapts the first subframe length to fit available transmission opportunities in the preempted unlicensed spectrum while maintaining proper encoding through the indication mechanism, optimizing both efficiency and complexity.
Data Source
AI summary
A data transmission method, device, and system to resolve a problem that encoding cannot be performed based on an incomplete subframe because a length of the incomplete subframe is unknown. A first device generates a first subframe and a second subframe according to first data, determines a redundancy version (RV) of the first subframe according to an RV of the second subframe, and sends M of N orthogonal frequency division multiplexing (OFDM) symbols of the first subframe and N OFDM symbols of the second subframe to a second device.