Orthogonal Uplink Channel Access for Dense WLAN Feedback
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Solution Overview
Problem
WLAN systems face inefficiencies in channel access, particularly with large numbers of stations competing for access, leading to reduced throughput and increased energy consumption, especially in scenarios like IEEE 802.11ah with up to six thousand devices, where distributed coordination function (DCF) and existing grouping mechanisms are inadequate for simultaneous uplink transmissions.
Innovation Solution
The implementation of coordinated orthogonal channel access (COCA) mechanisms that enable simultaneous uplink transmission of control frames, including capability indications, configuration, synchronization, and grouping strategies to manage multiple stations efficiently, reducing interference and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If distributed coordination function (DCF) is used for channel access, then the system can support a large number of stations, but throughput decreases and energy consumption increases
Solution Approach 1:
The patent segments the large group of stations into multiple COCA groups, where each group transmits uplink control frames simultaneously using orthogonal sequences. This segmentation allows parallel transmission within groups while maintaining manageable coordination overhead, thereby improving throughput while supporting large numbers of stations.
Solution Approach 2:
The patent implements periodic COCA transmission opportunities where stations in each group transmit uplink control frames at scheduled intervals using orthogonal sequences. This periodic structure enables efficient resource utilization and predictable throughput, addressing the productivity issue while maintaining support for many stations.
2Quantity of substance
If distributed coordination function (DCF) is used for channel access, then the system can support a large number of stations, but energy consumption increases
Solution Approach 1:
By segmenting stations into COCA groups with scheduled transmission opportunities, the patent reduces the contention overhead and idle listening time for each station. Stations only need to wake up at their designated transmission opportunities, significantly reducing energy consumption while supporting large numbers of stations.
Solution Approach 2:
The patent enables stations to autonomously determine their transmission timing based on group assignment and orthogonal sequence allocation. Each station self-manages its transmission schedule without continuous AP coordination, reducing both energy consumption and overhead while supporting scalable station numbers.
3Productivity
If contention-free channel access method like PCF is used, then channel access efficiency improves, but overhead increases
Solution Approach 1:
The patent segments the coordination function into group-level management rather than individual station management. The AP coordinates COCA groups rather than individual stations, significantly reducing overhead messages and complexity while maintaining efficient contention-free access for all stations within each group.
Solution Approach 2:
The patent merges multiple stations into COCA groups that share common transmission resources and orthogonal sequences. By combining stations into groups, the system reduces the number of individual coordination messages needed, lowering overhead while maintaining efficient channel access for all member stations.
4Productivity
If simultaneous uplink transmissions are enabled, then spectral efficiency improves, but interference management becomes more difficult
Solution Approach 1:
The patent changes the transmission parameters by assigning orthogonal sequences to different COCA groups. This parameter change (using orthogonal waveforms instead of random access) enables simultaneous transmissions while eliminating interference through mathematical orthogonality, improving spectral efficiency without increasing management complexity.
Data Source
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Figure 1C
AI summary
A wireless transmit/receive unit, WTRU, comprising a processor; and a transceiver, the processor and the transceiver configured to receive a trigger frame to transmit an uplink, UL, feedback response on a channel simultaneously with at least one other WTRU, wherein the trigger frame includes an indication of association IDs, AIDs, of WTRUs triggered by the trigger frame, and the processor and the transceiver further configured to transmit the UL feedback response on the channel an interframe space after the trigger frame.