NSTR AP Multi-Link Beacon Signaling for Non-Primary Link Unavailability
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Solution Overview
Problem
In wireless communications, particularly under IEEE 802.11 standards, multi-link devices (MLDs) with in-device coexistence interference cannot support simultaneous transmission and reception on non-simultaneous-transmission-and-reception (NSTR) link pairs, leading to issues with indicating the unavailability of non-primary links due to channel measurement, co-existence requirements, or power-save reasons, as Beacon and Probe Response frames are not allowed on these links.
Innovation Solution
Implement schemes for link availability indication on non-primary links using Target Beacon Transmission Time (TBTT) references and Quiet Information Elements (IEs) in Beacon and Probe Response frames, including parameters like Count, Period, and Duration to indicate link unavailability or quiet intervals, and utilizing Per-STA Profile sub-elements and Reduced Neighbor Report (RNR) elements to convey unavailability information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If Beacon frames and Probe Response frames are not transmitted on the non-primary link of an NSTR link pair, then in-device coexistence interference is avoided, but the ability to indicate link unavailability is lost
Solution Approach 1:
The patent uses the primary link as an intermediary to convey information about the non-primary link's availability. By including unavailability indication information in Beacon frames or Probe Response frames transmitted on the primary link, the system can indicate the status of the non-primary link without transmitting frames directly on it, thus avoiding interference while still providing necessary information.
Solution Approach 2:
The patent segments the information transmission function by separating the indication of link unavailability from the actual data transmission on the non-primary link. The unavailability indication is transmitted on the primary link while the non-primary link remains dedicated to data transmission or remains silent, allowing the system to maintain clear functional separation between control information and data traffic.
2Object-affected harmful factors
If the non-primary link is kept silent to avoid interference, then coexistence requirements are met, but channel measurement capability is reduced
Solution Approach 1:
The patent implements periodic channel measurement during designated quiet intervals on the non-primary link. Instead of continuous measurement that would cause constant interference, the system schedules periodic measurement opportunities when the link is temporarily made available, balancing the need for accurate channel information with the requirement to minimize interference during normal operation.
3Use of energy by moving object
If the non-primary link is designated as unavailable for power-save reasons, then energy consumption is reduced, but network connectivity information is lost
Solution Approach 1:
When the non-primary link is placed in a power-save state, the primary link acts as an intermediary to communicate the availability status. The AP MLD includes unavailability indication information in frames transmitted on the primary link, informing STAs about the current state of the power-save link without requiring the power-save link to be active for communication.
Data Source
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AI summary
A first access point, AP, which is affiliated with a AP multi-link device, MLD, operating on a non-simultaneous-transmission-and-reception, NSTR, link pair comprising a primary link and a non-primary link, generates a beacon frame or probe response frame (710). The first AP then transmits the beacon frame or probe response frame on a link that is not the non-primary link to indicate that a second AP affiliated with the NSTR AP MLD and operating on the non-primary link is unavailable, quiet or disabled (720).