Extended-Code Uplink Transmission for RFID Tag Collision Avoidance
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Solution Overview
Problem
The Q-selection algorithm in passive RFID systems leads to time domain resource waste and electronic tag response latency due to uplink signal conflicts and inefficient utilization of resources.
Innovation Solution
Implementing code division multiplexing (CDM) by using extended codes to orthogonalize uplink signals, allowing multiple electronic tags to transmit simultaneously, thereby reducing conflicts and increasing communication distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Q-selection algorithm is used to avoid uplink signal collisions, then signal conflict is reduced, but time domain resource waste and response latency increase
Solution Approach 1:
The patent transitions from time-domain collision avoidance (Q-selection algorithm) to code-domain separation (CDM). By assigning different extended codes to multiple electronic tags, the system enables simultaneous uplink transmissions without collision, eliminating the need for time-slot arbitration and thereby reducing response latency while maintaining conflict avoidance.
Solution Approach 2:
The patent changes the fundamental parameter for collision avoidance from time slot selection to code sequence selection. By using extended codes with orthogonal properties, the system allows multiple tags to transmit concurrently on the same time-frequency resources, transforming the collision avoidance mechanism from temporal to spectral/codematic domain.
2Reliability
If the Q-selection algorithm is used to avoid uplink signal collisions, then signal conflict is reduced, but time domain resource utilization decreases
Solution Approach 1:
The patent moves the collision avoidance mechanism from the time dimension to the code dimension. By using code division multiplexing with extended codes, multiple tags can occupy the same time resources simultaneously, thereby fully utilizing time domain resources while maintaining conflict avoidance through code orthogonality.
Solution Approach 2:
The patent merges multiple uplink transmissions that would traditionally occur at different time slots into a single simultaneous transmission window. By combining code-based separation with time-domain concurrency, the system achieves both conflict avoidance and maximum resource utilization.
3Loss of time
If code division multiplexing is implemented to allow simultaneous transmissions, then response latency is reduced, but signal conflict may occur without proper code orthogonalization
Solution Approach 1:
The patent applies preliminary orthogonalization processing to the extended codes before transmission. By pre-designing and assigning orthogonal extended codes to different tags, the system ensures that simultaneous transmissions will not interfere with each other, thereby enabling low-latency concurrent communication while maintaining high reliability through built-in code orthogonality.
Data Source
AI summary
Provided in the embodiments of the present application are an information transmission method and apparatus, and a first communication node and a second communication node. The method comprises: receiving an extended preamble sequence based on a selected extended code and transmitted by a second communication node; determining a target extended code based on the extended preamble sequence, where the target extended code is an extended code selected by a single second communication node in an extended code set; and transmitting indication information of the target extended code.