Trigger Frame Channel Sensing for Uplink Transmission
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Solution Overview
Problem
Current wireless local area networks (WLANs) face challenges in efficiently managing uplink transmissions from multiple client stations, particularly in determining idle subchannels for simultaneous transmissions, which can lead to interference and reduced throughput.
Innovation Solution
The implementation of a method where a client station receives a trigger frame from an access point indicating whether to perform channel sensing to determine if subchannels are idle before transmitting an uplink physical layer data unit, allowing for either immediate transmission without sensing or delayed transmission only after confirming the subchannels are idle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If channel sensing procedure is performed before uplink transmission, then interference is reduced and transmission reliability is improved, but transmission delay increases and throughput decreases
Solution Approach 1:
The patent applies dynamics by making the channel sensing requirement flexible and adjustable. The access point dynamically indicates whether channel sensing is required through the trigger frame, allowing the system to adapt between performing sensing (for reliability) and not performing sensing (for speed) based on current network conditions and AP decisions.
Solution Approach 2:
The patent changes the parameter of channel sensing requirement from a fixed mandatory condition to a variable condition indicated by the AP. The trigger frame includes an indication parameter that specifies whether channel sensing is required, allowing the system to adjust this parameter based on network state to balance reliability and delay.
2Reliability
If channel sensing procedure is performed to determine idle subchannels, then transmission reliability is improved, but network throughput and efficiency decrease due to additional sensing time
Solution Approach 1:
The system dynamically adjusts whether channel sensing is performed based on AP indication in the trigger frame. This allows the network to switch between reliable sensing-based transmission and efficient direct transmission depending on current conditions, optimizing the balance between reliability and throughput.
Solution Approach 2:
The access point performs preliminary assessment and indicates in advance whether channel sensing is required through the trigger frame. This preliminary action allows client stations to prepare appropriately, performing sensing only when necessary, thereby maintaining reliability when needed while preserving throughput when conditions allow.
3Speed
If immediate uplink transmission is performed without channel sensing, then transmission speed and throughput are improved, but interference increases and transmission reliability decreases
Solution Approach 1:
The patent makes the transmission mode dynamic by allowing the AP to indicate whether channel sensing is required. This enables the system to switch between immediate transmission (for speed) and sensing-based transmission (for interference reduction) based on real-time network conditions.
Solution Approach 2:
The access point provides feedback to client stations through the trigger frame indication of whether channel sensing is required. This feedback mechanism allows the AP to inform stations about the appropriate transmission approach based on current network state, enabling speed when conditions permit and interference reduction when necessary.
4Object-affected harmful factors
If channel sensing is required for all uplink transmissions, then interference management is improved, but device complexity and operational overhead increase
Solution Approach 1:
The patent reduces complexity by making channel sensing dynamic rather than mandatory for all transmissions. The AP indicates whether sensing is required based on current conditions, allowing stations to perform sensing only when necessary, thereby reducing operational overhead while maintaining interference management when needed.
Solution Approach 2:
Instead of requiring full channel sensing for all uplink transmissions, the patent applies partial action by requiring sensing only when the AP indicates it is necessary. This selective approach reduces operational overhead and device complexity while maintaining adequate interference management through targeted sensing.
Data Source
AI summary
A client station receives from an access point (AP) a downlink packet that includes a trigger frame that is configured to prompt the client station to transmit an uplink packet to the AP. The trigger frame includes an indication of whether the client station is required to perform a channel sensing procedure to determine if one or more subchannels are not idle prior to transmitting the uplink packet. In response to the trigger frame indicating that the client station is required to perform the channel sensing procedure: the client station does not transmit the uplink packet in response to determining that the one or more subchannels are not idle. In response to the trigger frame indicating that the client station is not required to perform the channel sensing procedure, the client station transmits the uplink packet without measuring the one or more energy levels in the one or more subchannels.