WLAN Trigger-Frame Uplink Access for Multi-User Random Access
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Solution Overview
Problem
Existing IEEE 802.11 specifications do not effectively support multi-user concurrent random access for high efficiency wireless local area networks (WLANS) in high-density scenarios, leading to inefficient channel access and increased system delay.
Innovation Solution
Implement mechanisms for multi-user concurrent random access (MU-RA) using trigger frames to synchronize and schedule uplink transmissions, allowing multiple stations to access the channel simultaneously, reducing collisions and enhancing channel utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing IEEE 802.11 specifications are used for channel access, then device compatibility is maintained, but channel access efficiency deteriorates in high-density scenarios
Solution Approach 1:
The channel access mechanism is segmented into two distinct types: traditional random access for compatibility and trigger-based scheduled access for efficiency. The access point segments the uplink transmission opportunities by sending trigger frames that allocate specific resource units to specific stations, allowing simultaneous transmissions without collisions. This segmentation resolves the contradiction by enabling efficient multi-user access while maintaining the traditional random access mechanism for backward compatibility.
Solution Approach 2:
Trigger frames serve as an intermediary mechanism between the access point and stations. These trigger frames carry scheduling information and resource unit allocations, mediating the channel access process. Instead of stations directly competing for channel access, the access point uses trigger frames to coordinate and schedule transmissions, thereby improving channel access efficiency while maintaining system compatibility through a standardized frame format.
2Loss of time
If traditional random access is used, then implementation simplicity is maintained, but system delay increases due to collisions
Solution Approach 1:
The access point performs preliminary scheduling actions by sending trigger frames before actual uplink transmissions. These trigger frames pre-allocate resource units and coordinate transmission timing, preventing collisions before they occur. This preliminary action eliminates the need for retransmissions and reduces system delay, while the trigger frame format maintains ease of operation by using standardized IEEE 802.11 frame structures.
3Productivity
If multi-user concurrent access is enabled, then channel utilization efficiency is improved, but compatibility with existing specifications deteriorates
Solution Approach 1:
The trigger frame mechanism is designed with universality to serve multiple functions: it maintains backward compatibility with existing IEEE 802.11 specifications while simultaneously enabling advanced multi-user concurrent access. The trigger frames use standardized frame formats that existing stations can recognize, while the scheduling information within them enables efficient resource allocation. This multi-functionality allows the system to support both traditional and advanced access modes, improving channel utilization without sacrificing compatibility.
Data Source
AI summary
Methods and apparatus are described. A station includes a transceiver and a processor, which receive a trigger frame for an uplink (UL) transmission. The trigger frame includes an indication of resource units (RUs) for random access in an upcoming UL high efficiency trigger based packet data convergence protocol protocol data unit and an indication that the trigger frame is a poll for a buffer status report of the STA. The processor and the transceiver transmit a buffer status of the STA using a selected one of the indicated RUs.