MU-RTS CTS Apparatus for WLAN Channel Switching
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Solution Overview
Problem
In wireless local-area networks (WLANs), existing methods struggle to efficiently manage multi-user request-to-send (MU-RTS) and clear-to-send (CTS) frames, especially when dealing with a mix of high-efficiency (HEW) and legacy devices, leading to interference and resource inefficiencies due to the need for synchronization and channel switching.
Innovation Solution
The implementation of a method that includes generating and transmitting MU-RTS and CTS frames with specific frame structures and bandwidth configurations, allowing HEW devices to operate on secondary channels while maintaining synchronization with the primary channel, and using trigger frames to indicate transmission periods, thereby reducing frame loss during channel switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MU-RTS and CTS frames are transmitted with specific bandwidth configurations to enable concurrent communication with HEW and legacy devices, then resource utilization and bandwidth efficiency are improved, but frame loss during channel switching increases
Solution Approach 1:
The patent segments the transmission medium into multiple channels (primary channel and secondary channels) with different bandwidth configurations. HEW devices can operate on secondary channels while legacy devices use the primary channel, allowing concurrent communication without interference. This segmentation resolves the contradiction by enabling resource utilization improvement through multi-channel operation while maintaining frame reliability through proper channel assignment and synchronization mechanisms.
Solution Approach 2:
The patent introduces trigger frames as intermediary signals that coordinate MU-RTS and CTS transmissions. These trigger frames provide synchronization information and bandwidth configuration details to devices, enabling them to switch channels properly without losing frames. The intermediary trigger frame mechanism ensures that devices can utilize multiple channels efficiently while maintaining frame integrity during transitions.
2Productivity
If HEW devices operate on secondary channels while maintaining synchronization with the primary channel, then bandwidth efficiency is improved, but device complexity increases due to synchronization requirements
Solution Approach 1:
The patent implements periodic synchronization mechanisms where HEW devices periodically check the primary channel for trigger frames and synchronization information. This periodic action allows devices to maintain synchronization with the primary channel while operating on secondary channels, improving bandwidth efficiency without requiring continuous complex synchronization protocols. The periodic nature reduces the computational burden compared to continuous synchronization.
Solution Approach 2:
The patent enables HEW devices to autonomously determine their operating parameters by reading synchronization information from trigger frames on the primary channel. Devices self-configure their secondary channel operations based on the bandwidth and timing information provided in the trigger frames, reducing the need for complex centralized control and simplifying the overall synchronization mechanism while maintaining high bandwidth efficiency.
3Productivity
If multiple devices share the same wireless resources, then network capacity is improved, but interference between devices increases
Solution Approach 1:
The patent segments the wireless medium into multiple channels and assigns different devices to different channels based on their capabilities (HEW vs. legacy). This spatial and frequency segmentation reduces interference between devices sharing the network, while still allowing high network capacity through parallel transmissions on multiple channels. The segmentation enables simultaneous MU-RTS/CTS exchanges without mutual interference.
Solution Approach 2:
The patent applies different transmission parameters and protocols to different devices based on their local characteristics. HEW devices use advanced features like OFDMA and wider bandwidths on secondary channels, while legacy devices use traditional protocols on the primary channel. This local quality approach allows each device to operate optimally in its assigned context, maximizing network capacity while minimizing interference through protocol-appropriate transmissions.
Data Source
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AI summary
Methods, apparatuses, and computer readable media for MU-RTS and CTS in WLANs are disclosed. An apparatus is disclosed that comprises circuitry that is configured to generate a packet to indicate a multi-user request-to-send (MU-RTS), wherein the packet indicates one or more HEW station information fields, wherein the one or more HEW station information fields comprise an address of a HEW station and an indication of a bandwidth for the HEW station to transmit one or more clear-to-send (CTS) packets; and transmit the packet to the one or more HEW stations. A HEW device is disclosed that includes circuitry configured to receive a multi-user request-to-send (MU-RTS); copy a scramble seed from the MU-RTS to a clear-to-send (CTS) packet; and transmit the CTS packet.