Overlapping Channel Plans for RFID Spectrum Coexistence
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Solution Overview
Problem
Conventional RFID systems face challenges in parallel operation within the same frequency band, leading to interference and inefficient frequency spectrum allocation, as they cannot distinguish between occupied channels by RFID systems and other radio systems, resulting in restricted frequency allocation and increased waiting times.
Innovation Solution
The method involves dividing the frequency band into two overlapping channel plans, where the center frequencies of one plan are defined on the boundaries of the other, allowing RFID systems to analyze and determine occupied channels, enabling coexistence with other radio systems by selecting non-overlapping channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If RFID systems use the same frequency band as other radio systems, then frequency spectrum utilization is improved, but channel interference and inability to distinguish occupied channels worsens
Solution Approach 1:
The frequency band is segmented into two overlapping channel plans with different channel assignments. The first channel plan is used by other radio systems while the second channel plan is dedicated to RFID systems. This segmentation allows both systems to operate simultaneously in the same frequency band without interference, as each system monitors and avoids channels occupied by the other system.
2Reliability
If conventional RFID systems occupy transmission channels exclusively, then communication reliability is improved, but frequency allocation restriction and waiting times worsen
Solution Approach 1:
The channel occupation strategy is made dynamic through continuous monitoring of channel occupancy status. RFID read/write stations dynamically select channels from the second channel plan based on real-time detection of which channels are currently occupied by other radio systems. This dynamic adaptation eliminates fixed waiting times and allows immediate transmission on available channels, improving both reliability and reducing time loss.
3Object-affected harmful factors
If spatially adjacent transmitters use different channels, then transmission signal interference is reduced, but frequency spectrum efficiency deteriorates
Solution Approach 1:
The problem is solved by adding a dimensional aspect to channel allocation - instead of simply assigning different channels to adjacent transmitters, the system creates two overlapping channel plans where RFID systems and other radio systems operate on different channel assignments within the same frequency band. This dimensional approach allows spatially adjacent transmitters to use the same physical frequency while maintaining signal separation through systematic channel plan differentiation.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The method involves dividing a frequency band (10) into a set of channels (cA1-cA6, cB1-cB5) by channel planes (A, B). The channels of the channel planes overlap with one another, and central frequencies (fc) of one of the channel planes are defined such that the central frequencies lie on channel borders of the other channel plane. Busy conditions of the channels of the latter channel plane and/or the former channel plane are analyzed by a radio frequency identification (RFID) system, where the planes lie in the same frequency band.