Trigger Frame Resource Allocation for Uplink Multi-User WLAN
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Solution Overview
Problem
Wireless local area network (WLAN) devices face performance degradation due to increased interference from neighboring devices, particularly in environments with diverse applications like video streaming, where real-time requirements demand improved power consumption and resource allocation efficiency for battery-operated devices.
Innovation Solution
The implementation of trigger frames for facilitating uplink (UL) transmissions in WLAN systems, allowing for the reuse of previously assigned resources for UL multi-user (MU) transmissions, and the use of traffic specification (TSPEC) frames to support orthogonal frequency division multiple access (OFDMA) and MU-MIMO transmissions, enabling efficient resource allocation and retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If trigger frames are used to schedule uplink multi-user transmissions with resource allocation information, then resource allocation efficiency is improved and overhead is reduced, but device complexity increases due to the need to process and interpret trigger frame formats
Solution Approach 1:
The trigger frame is segmented into distinct functional fields: common information field (containing UL transmission parameters applicable to all stations), resource allocation field (containing station-specific resource assignments), and per-station information fields. This segmentation allows receiving devices to efficiently parse only the relevant portions for their specific needs, reducing processing complexity while maintaining comprehensive resource allocation capabilities.
Solution Approach 2:
The trigger frame contains preliminary resource allocation information and transmission parameters that are determined in advance by the access point. Stations receive this pre-configured information before actual uplink transmission, allowing them to prepare their transmissions without real-time negotiation, thereby improving allocation efficiency while reducing on-the-fly processing complexity.
2Productivity
If resource units are assigned to stations for uplink OFDMA transmission, then simultaneous multi-user transmissions are enabled improving throughput, but interference from neighboring devices increases due to denser device deployment
Solution Approach 1:
The system assigns specific resource units (subcarriers, time slots) to specific stations based on their individual channel conditions, location, and traffic requirements. This localized resource allocation ensures that each station transmits on optimally suited resources, maximizing throughput while minimizing co-channel interference with neighboring devices through frequency and spatial separation.
Solution Approach 2:
The patent extends resource allocation from traditional time-domain only to include frequency-domain dimensions through OFDMA. By allocating different frequency subcarriers to different stations simultaneously, the system increases throughput in the frequency dimension while maintaining temporal separation, thereby reducing time-domain interference effects in dense deployments.
3Productivity
If trigger frames include complete resource allocation information for each station, then resource utilization is optimized, but frame overhead increases consuming more airtime and power
Solution Approach 1:
The trigger frame's common information field contains UL transmission parameters (such as modulation and coding schemes, guard interval settings, and transmission power levels) that are universally applicable to all scheduled stations. This multi-functional field serves all stations simultaneously, reducing the need for repetitive per-station parameter specifications and thereby minimizing overhead while maintaining optimized resource utilization through centralized parameter definition.
4Reliability
If battery-operated devices transmit frequently to meet real-time application requirements, then application performance is improved, but power consumption increases
Solution Approach 1:
The system implements periodic uplink transmission opportunities scheduled by trigger frames sent at regular intervals from the access point. Battery-operated devices can enter low-power states between these periodic opportunities, waking only to transmit when triggered, thereby maintaining real-time application performance through regular updates while minimizing power consumption by avoiding continuous monitoring and transmission preparation.
Data Source
AI summary
In wireless communications for multi-users, an access point may generate a trigger frame, which may include a trigger indication. The trigger indication may indicate whether a second trigger frame will be transmitted during a time interval. The trigger indication may use a single bit. The trigger frame may also include resource allocation for one or more stations. When the access point transmits the trigger frame, the station(s) may transmit an uplink frame(s) in response to the trigger frame. The access point may transmit a second trigger frame in the time interval. In response to the second trigger frame, the station(s) may transmit additional uplink frame(s) to the access point. The station(s) may save the resource allocation included in the trigger frame and utilize the same resource allocation for the uplink frame(s) and the additional uplink frame(s). Other methods, apparatus, and computer-readable media are also disclosed.