RFID Network Synchronization via Reader Service Signal
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Solution Overview
Problem
Existing RFID networks face challenges in managing interference between read/write stations due to their long range and limited frequency channels, leading to inefficient and unreliable operation, especially in large-scale systems where synchronization and frequency allocation methods are inadequate.
Innovation Solution
A method utilizing a reader service signal for direct communication between read/write stations on the physical air interface, where a collecting station provides structure and coordination data to ensure synchronous operation, with a reader service channel and time slot for service purposes, allowing for dynamic allocation of frequency channels and time slots, and enabling frequency hopping based on pseudo-random patterns to prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If read/write stations operate on different frequency channels to prevent mutual interference, then interference between stations is reduced, but the number of available frequency channels is limited and insufficient for large-scale systems
Solution Approach 1:
The system segments the frequency channel usage by introducing time slots, creating a time-division multiplexing scheme where different read/write stations operate on the same frequency channel at different times, thus preventing interference while allowing more stations than there are frequency channels
Solution Approach 2:
The system dynamically allocates frequency channels and time slots to read/write stations based on their operational needs and interference conditions, allowing flexible adaptation to changing network conditions rather than fixed static allocation
2Adaptability or versatility
If read/write stations share frequency channels and time axis in large-scale systems, then more stations can operate, but mutual interference occurs when multiple stations transmit simultaneously
Solution Approach 1:
The system implements periodic time slots for read/write operations, where each station is assigned specific time windows to transmit, creating a rhythmic structured operation that prevents simultaneous transmissions on the same channel and eliminates interference
Solution Approach 2:
A coordinating entity or protocol acts as an intermediary to manage frequency channel and time slot allocation among read/write stations, ensuring that transmission schedules are synchronized and interference-free operation is maintained across the network
3Reliability
If synchronization lines are laid between read/write stations for coordination, then interference is prevented through fixed resource allocation, but the complexity and cost of wiring increases in large areas
Solution Approach 1:
The system replaces the mechanical wiring-based synchronization approach with wireless communication methods, using radio frequency signals to carry synchronization and coordination information between read/write stations, thereby eliminating the need for physical synchronization lines while maintaining reliable coordination
4Ease of operation
If wire-based data bus is used for allocating transmission channels and power, then resource allocation can be controlled, but the time response is unknown and synchronous operation is not directly possible
Solution Approach 1:
The system replaces the wire-based data bus with wireless communication protocols that operate directly over the air interface, enabling real-time exchange of allocation information and synchronization signals with known and controllable timing characteristics, thus achieving synchronous operation
Data Source
AI summary
The invention relates to a method for operating an RFID network consisting of a number of read-write stations (1, 2, 3, 11, N0-N17), for which a reader service signal (9, 105) is modulated onto a read-write signal that is required to process a number of electronic labels (6). According to the invention, the following steps are carried out: at least one read-write station (1 2, 3, 11, N0-N17) is entrusted with the function of a master (100) that has stored a network structure (110) comprising structure data and a co-ordination plan containing co-ordination data; the master or masters transmit(s) (100) at least corresponding data for an organized synchronous network operation to the read-write stations (1, 2, 3, 11, N0-N17) periodically and/or on demand, so that the read-write stations (1, 2, 3, 11, N0-N17) do not interfere with one another during the read-write operation. This is achieved using a number of time slots (21, 31, 41) and a number of frequency channels (20, 30, 40), a service frequency channel (reader service channel, RSK) and/or a service time slot (reader service time, RST) being available and used to synchronize and modify the structure and co-ordination data between the master (100) and the read-write stations (1, 2, 3, 11, N0-N17).