RFID Beamforming Antenna Array for Interference Nulling
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Solution Overview
Problem
Conventional RFID systems face limitations in transmission distance, reliability, and bandwidth usage due to the need for close proximity between RFID tags and readers, leading to interference and collisions, especially in large areas or indoor environments.
Innovation Solution
The use of an antenna array system that transmits interrogation signals, processes signals to adjust relative phase, and combines them to form beam-steered signals, allowing for improved signal gain, interference reduction, and accurate tag location determination through spatial multiplexing and beamforming techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RFID systems use close proximity between reader and tags, then communication reliability is improved, but transmission distance is limited
Solution Approach 1:
The patent divides the coverage area into multiple zones using multiple base stations, each handling a subset of tags. This segmentation allows each base station to maintain reliable communication with nearby tags while collectively covering a larger transmission distance through the distributed network of base stations.
Solution Approach 2:
The patent introduces spatial dimensionality through antenna arrays and beamforming techniques. By controlling the spatial distribution and phase of signals across multiple antenna elements, the system extends effective communication distance while maintaining reliability through directional beam formation that focuses energy on target tags.
2Area of stationary object
If multiple base stations are deployed to cover large areas, then coverage area is improved, but bandwidth usage increases
Solution Approach 1:
The patent merges the processing capabilities of multiple base stations through a centralized computer system that coordinates communication with all tags across the network. This consolidation allows efficient bandwidth management and resource allocation, reducing total bandwidth consumption compared to independent base station operations while maintaining extensive coverage area.
Solution Approach 2:
The centralized computer system performs multiple functions including coordinating multiple base stations, managing tag communications across different frequency channels, and processing data from all sensors. This multi-functionality reduces redundant bandwidth usage by sharing processing resources across the entire network rather than duplicating capabilities at each base station.
3Loss of information
If base station processes information from every tag within range, then comprehensive data collection is improved, but available bandwidth decreases
Solution Approach 1:
The patent assigns different frequency channels to different spatial zones or tag groups, allowing simultaneous communication with multiple tags without interference. This local frequency allocation enables comprehensive data collection from all tags while maintaining available bandwidth through frequency division multiplexing, as each base station handles only the tags assigned to its frequency channel.
Solution Approach 2:
The system uses periodic time-division multiplexing where base stations take turns communicating with different tag groups at different time intervals. This periodic scheduling allows complete data collection from all tags across the network while managing bandwidth consumption by limiting simultaneous transmissions, with each base station processing information from its assigned tags during designated time slots.
Data Source
AI summary
A multi-protocol, multi-band array antenna system may be used in Radio Frequency Identification (RFID) system reader and sensory networks. The antenna array may include array elements with an integrated low noise amplifier. The system may employ digital beam forming techniques for transmission and steering of a beam to a specific sensor tag or group of tags in a cell. The receive beam forming network is optimized for detecting signals from each sensor tag. Narrow and wideband interferences may be excised by an interference nulling algorithm. Space division multiplexing may be used by the antenna system to enhance system processing capacity.