RFID Reader Data Extraction Using Orthogonal Code Despread
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Solution Overview
Problem
Conventional RFID communication systems fail to recover data from multiple RFID tags simultaneously, leading to inefficiencies in bandwidth utilization and throughput.
Innovation Solution
The system employs spread spectrum data stored in RFID tags, using orthogonal codes corresponding to each tag's identification, allowing the RFID reader to extract original data from multiple tags by despreading the received spread spectrum data with corresponding orthogonal codes, thereby enabling simultaneous communication with multiple tags.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple RFID tags simultaneously transmit data to the RFID reader using conventional methods, then the RFID reader cannot recover the data from multiple tags, but if sequential access is used, then bandwidth utilization and throughput are reduced
Solution Approach 1:
The data transmission from multiple RFID tags is segmented using orthogonal codes, where each tag's data is modulated with a unique orthogonal code sequence. This segmentation allows the reader to separate and recover individual tag data from the combined signal by correlating with the respective orthogonal codes, enabling simultaneous data recovery from multiple tags without collision.
Solution Approach 2:
The patent introduces a new dimension of orthogonal coding in the signal space, transforming the problem from time-sequential access to code-division multiplexing. By mapping each tag's data onto a different orthogonal code dimension, the system enables parallel data transmission and recovery, significantly improving throughput while maintaining data recovery capability.
2Productivity
If spread spectrum data is transmitted from multiple RFID tags simultaneously, then bandwidth utilization improves, but the complexity of extracting original data increases
Solution Approach 1:
The RFID reader stores copies of the orthogonal codes used by each RFID tag. When extracting data, the reader correlates the received spread spectrum signal with the stored orthogonal code copies, enabling efficient separation and recovery of individual tag data without requiring complex real-time code generation or synchronization mechanisms at the tag side.
3Productivity
If orthogonal codes are assigned to multiple RFID tags for simultaneous communication, then throughput improves, but the system complexity increases
Solution Approach 1:
Orthogonal codes are pre-assigned to each RFID tag based on their identification numbers during system initialization or tag registration. This preliminary assignment eliminates the need for complex real-time code allocation and management during operation, reducing system complexity while enabling simultaneous communication through code-division multiplexing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach efficiently utilizes communication channel bandwidth and improves throughput by allowing the RFID reader to recover original data from multiple tags without requiring each tag to perform spreading operations, simplifying implementation and enhancing system performance.
Implementation Method 1
The RFID reader transmits a command to the RFID tags by designating a RFID tag to respond and the designated RFID tag transmits data to the RFID reader in response to the command
Implementation Method 2
The plurality of spread spectrum data may be generated by spreading the plurality of original data with a plurality of orthogonal codes respectively corresponding to the plurality of RFID tags
Implementation Method 3
A plurality of original data respectively corresponding to the plurality of RFID tags are simultaneously extracted from the plurality of spread spectrum data at the RFID reader
Data Source
AI summary
In a method of communicating in a radio frequency identification (RFID) system including a RFID reader and a plurality of RFID tags, a plurality of spread spectrum data are stored in the plurality of RFID tags. The plurality of spread spectrum data are transmitted from the plurality of RFID tags to the RFID reader. A plurality of original data respectively corresponding to the plurality of RFID tags are simultaneously extracted from the plurality of spread spectrum data at the RFID reader.