WUR Beacon Scheduling for Duty Cycled IoT Frame Reception
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Solution Overview
Problem
The implementation of FDMA WUR transmissions in duty cycle mode faces challenges related to practical implementation, particularly in ensuring that WUR STAs receive scheduled broadcast WUR frames without missing them due to channel switching, which can disrupt service and limit the use of multiple WUR channels for efficient power management in IoT applications.
Innovation Solution
The proposed solution involves a communication apparatus and method that schedules WUR Beacon frames on a primary channel and allows WUR STAs to switch to this channel during designated Absence Grants within their duty cycle operation, ensuring they receive scheduled WUR frames while minimizing disruptions by defining specific periods for channel switching and using Absence Durations to account for channel switch margins and clock drifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If WUR STAs operate in duty cycle mode with channel switching to receive WUR Beacon frames, then power consumption is reduced and multiple channels can be utilized, but the risk of missing scheduled WUR frames increases due to channel switching delays and clock drifts
Solution Approach 1:
The patent applies preliminary action by defining Absence Grant periods in advance, during which WUR STAs are granted permission to switch channels to receive WUR Beacon frames. This pre-planned channel switching window ensures that STAs can reliably receive beacons without missing scheduled WUR frames, as the AP refrains from transmitting during these predetermined intervals. The Absence Duration parameter is calculated beforehand to account for channel switch margins and clock drifts, further ensuring reliable frame reception.
Solution Approach 2:
The patent introduces an intermediary mechanism through the Absence Grant concept, which acts as a mediator between the WUR STA's duty cycle operation and the AP's frame transmission schedule. The Absence Grant period serves as a coordinated interval where the AP temporarily suspends transmissions on the primary channel, allowing STAs to switch channels without risk of missing frames. This intermediary scheduling mechanism resolves the conflict between power-saving duty cycling and reliable frame reception.
2Productivity
If WUR STAs switch channels during duty cycle operation to receive WUR Beacon frames, then they can be assigned to non-primary channels for efficient FDMA transmission, but channel switching operations increase complexity and may cause service disruptions
Solution Approach 1:
The patent applies segmentation by dividing the WUR STA's operation into distinct segments: Absence Grant periods for channel switching and other periods for normal reception. This segmentation allows the STA to systematically switch to non-primary channels during designated Absence Grant intervals to receive WUR Beacon frames, while maintaining simple operation during regular periods. The channel switching complexity is confined to specific time segments rather than being continuous, improving overall network efficiency for FDMA transmissions.
3Reliability
If Absence Grant periods are defined to allow channel switching, then WUR STAs can reliably receive frames, but transmission efficiency is reduced due to idle periods where no WUR frames can be transmitted
Solution Approach 1:
The patent applies periodic action by implementing Absence Grant periods as regular, periodic intervals within the WUR STA's duty cycle operation. These periodic Absence Grant windows provide reliable frame reception opportunities while maintaining overall transmission efficiency. The AP can continue transmissions during non-Absence Grant periods, and the periodic nature of Absence Grants allows for predictable scheduling that minimizes impact on overall transmission productivity while ensuring reliable reception at regular intervals.
Data Source
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AI summary
The present disclosure provides a communication apparatus that comprises a receiver which, in operation, receives a wake-up radio (WUR) frame, during an on duration in a duty cycle, in a first channel assigned to the communication apparatus by an Access Point (AP), and receives a WUR Beacon frame in a second channel, a transmission of the WUR Beacon frame being scheduled at a target WUR beacon transmission time (TWBTT); and a processor which, in operation, operates the duty cycle, wherein, during a determined time from the TWBTT, any WUR frame is not transmitted in the first channel from the AP.