Multi-Channel LBT Protocol for RFI Resilient Wireless Transmission
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Solution Overview
Problem
Conventional listen before transmit protocols in wireless digital communication systems are rendered inoperable by localized radio frequency interference (RFI) sources, which can prevent nodes from transmitting data due to incorrect characterization of channel occupancy based solely on measured energy.
Innovation Solution
Implementing a multi-channel listen before transmit (LBT) protocol that assesses channel occupancy by sampling and quantifying energy across a range of frequencies, allowing nodes to identify clear channels and transmit data packets using appropriate modulation techniques, thereby avoiding interference from RFI sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional listen before transmit protocol uses measured energy to characterize channel occupancy, then nodes can avoid interference in normal operating scenarios, but localized RFI sources can falsely indicate channel occupancy and prevent legitimate transmissions
Solution Approach 1:
The patent segments the channel occupancy detection into multiple independent components: (1) energy measurement component, (2) signal presence detection component, and (3) temporal pattern analysis component. Each component operates independently and provides partial information about channel occupancy. The final occupancy determination integrates results from all three components, preventing any single component (including RFI-affected energy measurement) from making incorrect occupancy determinations alone.
Solution Approach 2:
The patent introduces an intermediary processing layer between the physical channel and the occupancy determination logic. This intermediary layer includes signal processing circuits that distinguish between legitimate signals and RFI by analyzing signal characteristics (modulation patterns, spectral content, temporal variations). The intermediary effectively mediates between raw energy measurements and final occupancy decisions, filtering out false indications from RFI sources.
2Productivity
If nodes transmit data packets using conventional LBT protocol, then data communication can proceed in absence of RFI, but transmission fails when target node cannot transmit acknowledgment due to localized RFI
Solution Approach 1:
The patent transitions from single-channel sequential communication to multi-dimensional communication by simultaneously utilizing multiple frequency channels. The source node transmits data packets on multiple channels in parallel, and the target node can acknowledge receipt on any of these channels. This dimensional expansion provides alternative pathways for communication, ensuring that if one channel is blocked by RFI for acknowledgment, other channels remain available for the same purpose.
Solution Approach 2:
The patent dynamically changes the operational parameters of the communication system by adapting the set of available channels based on real-time RFI conditions. When localized RFI is detected on a particular channel, the system automatically switches to alternative channels for both data transmission and acknowledgment. This parameter adaptation ensures continuous communication productivity despite the presence of RFI interference.
3Reliability
If multi-channel LBT protocol samples energy across range of frequencies, then nodes can identify clear channels and transmit data avoiding RFI interference, but system complexity increases compared to single-channel LBT
Solution Approach 1:
The patent segments the channel assessment function into multiple specialized sub-functions: (1) energy measurement module, (2) signal presence detection module, and (3) occupancy determination module. Each module handles a specific aspect of channel assessment and can operate independently. This segmentation allows the complex multi-channel assessment to be broken down into manageable tasks, reducing the complexity burden on any single component while maintaining high reliability in channel selection.
Data Source
AI summary
One embodiment of the present invention sets forth a technique for transmitting data in a listen before talk (LBT) wireless transmission regime. A digital radio receiver is configured to simultaneously receive and decode digital data transmissions from multiple radio channels. A digital radio transmitter is configured to listen to the multiple radio channels prior to transmitting digital data on a selected one of the multiple channels, based on locally determined channel occupancy. Optimal LBT efficiency is achieved within the set of multiple channels, thereby improving overall transmission efficiency between the transmitter and the receiver.