LoRa Backscatter Tag Multi-Access via Distributed Queuing
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Solution Overview
Problem
Conventional LoRa networks experience collisions when multiple LoRa tags transmit sensing data to a gateway, leading to inefficiencies and potential data loss.
Innovation Solution
Implementing a multi-access method for LoRa tags using backscatter communication that employs a distributed queuing (DQ) protocol, allowing tags to participate in contention by transmitting an Access Request Sequence (ARS) signal and managing conflict resolution and data transmission queues to avoid collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple LoRa tags transmit sensing data simultaneously to a gateway, then data transmission speed increases, but collision occurs leading to data loss
Solution Approach 1:
The contention window is divided into multiple time slots, and multiple tags are assigned to different slots through hashing functions. This segmentation of transmission time prevents simultaneous transmissions that cause collisions, while still allowing multiple tags to transmit data efficiently within the same contention window.
Solution Approach 2:
The gateway sends feedback signals to tags indicating whether their transmission was successful or if a collision occurred. Tags use this feedback to adjust their transmission behavior in subsequent contention windows, retransmitting only when conditions are favorable, thereby improving overall transmission reliability without sacrificing productivity.
2Reliability
If a distributed queuing protocol is implemented for collision avoidance, then data transmission reliability improves, but system complexity increases
Solution Approach 1:
Each LoRa tag independently calculates its own time slot assignment using a hashing function based on its ID and the contention window size. Tags autonomously determine their transmission timing without requiring complex centralized scheduling or inter-tag communication, thereby achieving reliable collision-free transmission while keeping individual tag complexity low.
Solution Approach 2:
The system uses simple mathematical parameters (hashing functions of tag IDs and contention window sizes) to determine transmission slots. By changing these parameters dynamically based on network conditions, the system achieves reliable collision avoidance without requiring complex protocol logic in each device.
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
Enables efficient and collision-free data transmission by ensuring that only successful contention participants transmit data, optimizing resource use in high-speed multi-channel environments.
Implementation Method 1
Backscatter communication means that radio waves are scattered in a direction opposite a progress direction. In the ITS field DSRC, backscatter is known as a passive tag system, which is opposite an active tag system.
Implementation Method 2
A tag reflects part of electromagnetic energy that returns to a base station in order to communicate data to a reader.
Data Source
AI summary
Proposed are a multi-access method and apparatus for a LoRa tag using backscatter communication. The multi-access apparatus for a LoRa tag using backscatter communication may include a contention slot unit configured to receive a signal for a contention participation request from a base station and participate in a contention according to a distributed queuing (DQ) protocol using a backscatter signal if data to be transmitted is present, an FBP unit configured to receive a result of the contention from the base station and check whether the result of the contention is a success, and a data slot unit configured to transmit sensed data to the base station using the backscatter signal if the result of the contention is a success.