Multi-Link WLAN RTS CTS Coordination for Non-STR Interference
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Solution Overview
Problem
In wireless local area network (WLAN) systems supporting multi-links, devices that do not support simultaneous transmit and receive (STR) operations face interference issues between adjacent links, preventing simultaneous transmission and reception due to signal interference, which hampers channel access and communication efficiency.
Innovation Solution
The method involves transmitting a request-to-send (RTS) frame in one link, receiving a clear-to-send (CTS) frame, and then transmitting data frames in both links while synchronizing the transmission times, using padding to align the end times of frames across links, and reconfiguring the transmit opportunity (TXOP) to ensure efficient data transmission despite non-STR capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multi-link operations are performed in adjacent bands, then communication speed is improved, but signal interference between links prevents simultaneous transmit and receive operations
Solution Approach 1:
The patent applies preliminary action by having the first device transmit an RTS frame in the first link before attempting data transmission. This RTS frame reserves the channel and notifies the second device of the upcoming transmission, allowing the second device to prepare for reception in the second link without actual signal interference occurring during the critical transmission phase.
Solution Approach 2:
The RTS-CTS mechanism acts as an intermediary coordination protocol between the first and second links. The RTS frame serves as a mediator signal that coordinates channel access between adjacent links, enabling the system to manage interference by establishing transmission rules before actual data transmission begins.
2Productivity
If simultaneous transmit and receive operations are attempted in adjacent links, then channel access efficiency is improved, but interference prevents proper channel access operations
Solution Approach 1:
The patent performs preliminary channel reservation by transmitting the RTS frame in the first link before initiating data transmission. This preliminary action establishes channel access rights and notifies the second device, ensuring that subsequent channel access operations in both links proceed reliably without interference-based failures.
Solution Approach 2:
The CTS frame received by the first device in response to the RTS frame provides feedback that confirms channel reservation and enables the first device to proceed with data transmission. This feedback mechanism ensures reliable channel access by verifying that the second device is ready to receive in the second link without interference.
3Productivity
If transmission time is extended to accommodate padding for synchronization, then transmission efficiency is improved, but transmission duration increases
Solution Approach 1:
The patent changes the parameter of transmission time by introducing padding that extends the transmission duration in the first link to match the reception time in the second link. This parameter adjustment ensures synchronization between links, allowing the first device to transmit data at the optimal time without interfering with the second link's reception operations.
Data Source
AI summary
Disclosed are a method and apparatus for transmitting and receiving data in a communication system supporting multiple links. A method for operation of a first device comprises the steps of: transmitting, in a first link from among multiple links, a first RTS frame to a second device; receiving, from the second device in the first link, a first CTS frame that is a response to the first RTS frame; when the first CTS frame is received, transmitting, in the first link, a first data frame to the second device; and transmitting, in a second link during transmission of the first data frame, a second RTS frame to the second device.