RA-RU Allocation for Low-Latency WLAN Traffic
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Solution Overview
Problem
In wireless local area networks (WLANs), buffered low-latency (LL) traffic frames from non-access point stations (non-AP STAs) often face delays in transmission due to lack of timely allocation of random access resource units (RA-RUs) during transmission opportunities (TXOP) held by access points (APs or other non-AP STAs, leading to inefficient communication.
Innovation Solution
The method involves an access point (AP) sending a trigger frame to allocate a RA-RU specifically for uplink LL traffic frame transmission, allowing non-AP STAs to transmit LL traffic frames without random backoff, and establishing a membership group for periodic RA-RU allocation, using new Uplink OFDMA Random Access (UORA) parameters and procedures that differ from standard protocols to ensure timely and efficient LL traffic frame communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If standard random access procedures are used for LL traffic, then resource allocation is general-purpose, but transmission latency increases due to lack of timely RA-RU allocation
Solution Approach 1:
The patent segments the random access resource units into dedicated LL RA-RUs and standard RA-RUs. The trigger frame includes a LL RA-RU allocation subfield that specifically identifies resource units allocated for low-latency traffic, separating them from general-purpose random access resources. This segmentation enables prioritized access for LL traffic while maintaining standard procedures for other traffic types.
Solution Approach 2:
The patent implements preliminary action by announcing LL RA-RU allocations in advance through trigger frames before the actual transmission opportunity occurs. The AP sends trigger frames that contain allocation information for LL RA-RUs, allowing non-AP STAs to prepare and immediately transmit LL traffic frames when the allocated resources become available, eliminating waiting delays.
2Productivity
If dedicated RA-RU allocation for LL traffic is implemented, then transmission efficiency improves, but protocol complexity increases
Solution Approach 1:
The patent achieves universality by designing the trigger frame structure to serve multiple functions: it contains both standard RA-RU allocation information and dedicated LL RA-RU allocation information. The same trigger frame mechanism is used for both standard and low-latency random access, allowing the system to handle different traffic types through a unified protocol framework rather than requiring separate protocols.
Solution Approach 2:
The patent applies parameter changes by modifying the trigger frame format to include a LL RA-RU allocation subfield with specific parameters such as LL RA-RU index, size, and timing information. These parameter additions enable dedicated resource allocation without fundamentally changing the overall random access protocol structure, maintaining compatibility while adding LL traffic support.
3Loss of time
If standard UORA backoff procedure is used, then resource contention is managed, but LL traffic experiences delays due to random backoff
Solution Approach 1:
The patent extracts the backoff mechanism from the LL traffic transmission path by providing dedicated LL RA-RUs that do not require participation in the standard UORA backoff procedure. Non-AP STAs with LL traffic can directly access their allocated LL RA-RUs without performing random backoff, OBO count selection, or decrement operations, effectively removing the source of delay while standard backoff continues to manage contention for non-LL traffic.
Data Source
AI summary
One example discloses a method for low-latency (LL) traffic frame communication between WLAN (wireless local area network) devices, including: sending a trigger frame from an access point (AP) configured to allocate a random access resource unit (RA-RU) to a non-access point station (non-AP STA); wherein the RA-RU enables the non-AP STA to transmit its low latency (LL) traffic information; and receiving, from the non-AP STA, an uplink LL traffic frame using the RA-RU that was allocated.