Grant-Free Multi-Channel Transmission for Collision-Resilient Detection
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Solution Overview
Problem
Grant-free or scheduling-free transmission in wireless communication systems faces challenges such as reduced reliability due to collisions in transmission signatures, pilot collisions, and susceptibility to channel fading, which affect the efficiency and accuracy of multi-user detection.
Innovation Solution
The solution involves transmitting messages through multiple channels with independently selected or generated pilot signals, spreading sequences, and channel indexes, using techniques like differential modulation and non-coherent demodulation to enhance reliability and reduce collisions, and employing orthogonal frequency division multiplexing with a long cyclic prefix to manage channel synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If grant-free transmission is used to reduce signaling overhead and latency, then transmission speed and system simplicity are improved, but transmission reliability deteriorates due to signature collisions and pilot collisions
Solution Approach 1:
The patent transitions from single-channel grant-free transmission to multi-channel transmission. Devices transmit messages across multiple transmission channels (e.g., physical uplink shared channels) with independently selected pilot signals and spreading sequences. This dimensional expansion from one channel to multiple channels reduces collision probability while maintaining the grant-free transmission speed advantage.
Solution Approach 2:
The patent changes key transmission parameters including selecting multiple transmission channels, independently selecting or generating pilot signals for each channel, choosing spreading sequences, and determining channel indexes. These parameter variations across multiple channels reduce signature collisions and pilot collisions while preserving the low-latency benefit of grant-free transmission.
2Reliability
If multiple transmission channels are used to improve reliability, then transmission reliability is improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent enables devices to autonomously select or generate pilot signals, spreading sequences, and channel indexes without requiring network coordination or grants. This self-service approach allows multi-channel transmission with enhanced reliability while avoiding the signaling overhead and complexity associated with centralized resource allocation.
Solution Approach 2:
The patent divides the transmission task across multiple independent channels, each with its own pilot signal and spreading sequence. This segmentation reduces the complexity of any single transmission instance while achieving overall higher reliability through diversity. The message is segmented across channels rather than concentrated in one channel.
3Measurement precision
If independently selected pilot signals are used to reduce pilot collisions, then multi-user detection accuracy is improved, but signal processing complexity increases
Solution Approach 1:
The patent employs dynamically selected or generated pilot signals for each transmission channel rather than static predetermined sequences. This dynamic approach reduces pilot collisions between different users and time instances, improving multi-user detection accuracy. The pilot signals adapt to current transmission conditions while maintaining manageable processing complexity through structured generation methods.
Data Source
AI summary
Techniques are described for a grant-free transmission. A wireless method includes generating and transmitting the same message via one or more transmission channels. The message includes information indicative of one or more channel indexes associated with the one or more transmission channels, one or more pilot signals associated with the one or more transmission channels, one or more spreading sequences associated with the one or more transmission channels, one or more scrambling sequences associated with the one or more transmission channels, or an interleaving technique associated with the one or more transmission channels.