Multi-link Time Synchronization via TSF Offset
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Solution Overview
Problem
In multi-link wireless communication systems, non-AP MLDs face challenges in time synchronization due to in-device coexistence interference, which prevents simultaneous transmission and reception on multiple links, necessitating an alternative method to convey time synchronization function (TSF) information for non-primary links.
Innovation Solution
The method involves transmitting a TSF offset value in frames like beacon, probe response, or association frames through Reduced Neighbor Report or multi-link elements, allowing non-AP MLDs to synchronize secondary links based on timestamp and offset information, enabling coordinated multi-link operations and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an NSTR AP MLD transmits Beacon and Probe Response frames only on the primary link, then in-device coexistence interference is avoided, but time synchronization information cannot be conveyed to non-AP MLDs operating on the non-primary link
Solution Approach 1:
The patent uses the primary link as an intermediary channel to convey time synchronization information for the non-primary link. The AP MLD transmits TSF offset values in Beacon or Probe Response frames on the primary link, which non-AP MLDs then use to synchronize their transmissions on the non-primary link, avoiding the need to transmit these frames directly on the interfered non-primary link
Solution Approach 2:
The patent transmits a copy of the time synchronization information (TSF offset value) on the primary link that represents the timing relationship for the non-primary link. This copied information allows non-AP MLDs to infer the correct transmission timing on the non-primary link without requiring direct frame transmission on that link
2Adaptability or versatility
If an NSTR MLD operates on two links with IDC interference, then multi-link operation capability is provided, but simultaneous transmit and receive cannot be supported on both links
Solution Approach 1:
The patent segments the link roles into primary and non-primary links. The primary link handles control plane operations including Beacon and Probe Response transmissions, while the non-primary link focuses on data plane operations. This segmentation allows the system to maintain multi-link operation capability while avoiding IDC interference by clearly separating the functions of each link
Solution Approach 2:
The patent implements dynamic link management where the AP MLD can designate different links as primary or non-primary based on interference conditions and operational requirements. The system can dynamically adjust which link performs timing synchronization functions, allowing flexible adaptation to changing interference patterns while maintaining reliable multi-link operation
3Object-generated harmful factors
If Beacon and Probe Response frames are not transmitted on the non-primary link, then in-device coexistence interference is reduced, but non-AP MLDs cannot obtain TSF information for the non-primary link
Solution Approach 1:
The patent uses the primary link as an intermediary to convey timing information that applies to the non-primary link. The AP MLD includes TSF offset values in frames transmitted on the primary link, which serve as a proxy for providing timing information that would otherwise require direct transmission on the non-primary link
Solution Approach 2:
The patent transmits time synchronization information in an alternative dimension - using the primary link's communication channel to convey timing data for the non-primary link. This dimensional shift allows the system to provide necessary synchronization information without occupying the non-primary link's communication resources
Data Source
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AI summary
Embodiments of the present invention are drawn to systems, apparatus (105) and methods that provide TSF information for a non-primary link to a non-AP STA (120) operating on a primary link to avoid IDC interference and improve wireless throughput and efficiency. The TSF information includes a TSF offset value used to determining the timing of subsequent transmissions over different wireless links. The TSF offset value can be carried in a beacon frame, probe response frame, association frame, through a Reduced Neighbor Report element or a multi-link element, for example. Beacon frames can include timestamp and TSF offset information transmitted periodically. Some wireless links may share a TSF clock or have fixed TSF offsets.