Ultra-Low Latency MAC Design for 802.11 MLO
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Solution Overview
Problem
Existing wireless communication technologies, such as Wi-Fi, face challenges in delivering time-critical packets with ultra-low latency, especially when all links are occupied and packets arrive out of schedule.
Innovation Solution
The proposed solution involves dividing long physical layer convergence protocol data units (PPDUs) into smaller PPDUs separated by short inter-frame spaces (SIFS) to facilitate ultra-low latency medium access control (MAC) design. This allows for staggered transmissions across multiple links, enabling urgent packets to be transmitted during the earliest SIFS time gap without aligning SIFS time gaps across links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If long PPDUs are used for transmission, then channel efficiency is improved, but latency increases when packets need to be transmitted urgently
Solution Approach 1:
The patent segments long PPDUs into smaller PPDUs separated by SIFS intervals. This allows the system to maintain channel efficiency through continuous transmission while enabling urgent packets to be injected at SIFS boundaries, thereby reducing latency without sacrificing overall channel utilization.
Solution Approach 2:
The patent introduces dynamic slot structure where SIFS gaps are strategically placed within the transmission sequence. This dynamic arrangement allows flexible insertion of urgent packets at appropriate SIFS points while maintaining the overall transmission efficiency through coordinated resumption of regular PPDUs.
2Productivity
If all links are occupied with regular transmissions, then channel utilization is maximized, but urgent packets cannot be transmitted
Solution Approach 1:
The patent preliminarily structures the transmission sequence with embedded SIFS gaps before urgent packets arrive. This pre-planned slot structure ensures that when urgent packets need to be transmitted, there are predetermined opportunities (SIFS points) available without disrupting the overall channel utilization strategy.
Solution Approach 2:
The SIFS gaps act as intermediaries between regular PPDUs. These intermediary time slots serve dual purposes: maintaining channel efficiency through continuous transmission while providing insertion points for urgent packets, thus mediating between channel utilization and adaptability requirements.
3Ease of operation
If SIFS time gaps are aligned across multiple links, then coordination is simplified, but latency increases for urgent packets
Solution Approach 1:
The patent applies different SIFS alignment strategies to different links based on local requirements. Rather than uniformly aligning all links, each link can have its SIFS gaps positioned optimally for its specific traffic patterns and urgency requirements, achieving lower overall latency while maintaining manageable coordination complexity.
Data Source
AI summary
This disclosure describes systems, methods, and devices related to ultra-low latency (ULL). A device may generate a first frame to be sent on a first link in a multi-link operation (MLO) with an multi-link device (MLD). The device may generate a second frame to be sent on a second link in the MLO with the MLD. The device may divide the first frame and the second frame into a first plurality of segments and a second plurality of segments separated by one or more first and second time gaps, respectively. The device may indicate to a first station device having a ULL packet to initiate a transmission of the ULL packet during an earliest time gap on the first link. The device may cause to send the one or more first and second plurality of segments on the first link and second link respectively.