LPWAN Gateway SPS Frame Allocation for Signal Overlap
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Solution Overview
Problem
Current LoRaWAN communication protocols experience signal overlap among terminal devices, leading to incomplete data reception and reduced network operation efficiency and reliability.
Innovation Solution
A Low Power Wide Area Network (LPWAN) communication mechanism that employs semi-persistent scheduling (SPS) cycles with beacons and network access requests to allocate non-overlapping SPS frames to terminal devices, ensuring synchronized data transmission and providing buffering frames for incomplete data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gateway receives data packets from each terminal device and sends data to terminal devices simultaneously, then the network can handle multiple terminal devices, but the signals overlap among different terminal devices causing incomplete data reception
Solution Approach 1:
The patent segments the data transmission process by dividing time into different slots. Each terminal device is assigned a specific time slot for data transmission, preventing simultaneous transmissions. This temporal segmentation resolves the signal overlap problem while maintaining the ability to serve multiple terminal devices, thereby improving both reliability and productivity.
Solution Approach 2:
The patent implements periodic action through the cyclic allocation of time slots to terminal devices. The gateway periodically grants access to terminal devices in a structured sequence, ensuring that each device gets a dedicated transmission opportunity. This periodic scheduling prevents signal overlap and ensures complete data reception while maintaining efficient network operation.
2Ease of operation
If simultaneous data transmission is enabled for all terminal devices, then network access is simplified, but signal overlap occurs reducing communication reliability
Solution Approach 1:
The patent applies preliminary action by having the gateway pre-allocate time slots to terminal devices before actual data transmission. The gateway sends grant messages that specify the allocated time slots in advance, allowing terminal devices to prepare their data for transmission. This preliminary scheduling simplifies the transmission process for devices while preventing signal overlap, thereby maintaining both ease of operation and communication reliability.
3Reliability
If the gateway grants SPS cycles to terminal devices, then data transmission can be scheduled without overlap, but the scheduling mechanism becomes more complex
Solution Approach 1:
The patent implements self-service by enabling terminal devices to autonomously manage their data transmission based on pre-granted SPS cycles. Once the gateway allocates time slots, terminal devices automatically use these slots for transmission without requiring continuous gateway intervention. This self-service approach reduces the complexity of ongoing scheduling while maintaining reliable non-overlapping data transmission.
Data Source
AI summary
The low power wide area network communication mechanism mainly allocates the semi-persistent scheduling (SPS) frames to the terminal devices having network access requirements sequentially by the gateway. The SPS cycle is composed of a plurality of SPS frames and at least one buffering frame. In each SPS cycle, a data reception window is activated by the gateway according to each allocated SPS frames; the SPS frames that the networked terminal devices belong to are activated synchronously within each SPS cycle in order for the networked terminal devices to perform a data transmission with the gateway during each SPS cycle and ensure that the data transmission does not overlap with the data sent by other terminal devices. The scheduling may be re-scheduled at a preset time interval to allocate the SPS frames of terminal devices that are inoperable or out of service area to the terminal devices having network access requirements.