WLAN Channel Access Adjustment After Failed PPDU Responses
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Solution Overview
Problem
In Wireless LAN (WLAN) communications, failed physical layer conformance procedure (PLCP) protocol data units (PPDUs due to interference or collisions lead to increased latency as communication devices extend their contention window, causing prolonged waiting times before retransmission.
Innovation Solution
Implement enhanced channel access principles that include altering transmission parameters, deferring or shortening beacon frames, prioritizing block acknowledgement requests, and changing TXOP duration to facilitate timely retransmissions and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a communication device extends its contention window after a failed PPDU, then reliability of channel access is improved, but latency increases due to prolonged waiting times before retransmission
Solution Approach 1:
The patent applies dynamics by making the contention window size adaptive rather than static. The contention window is dynamically adjusted based on the outcome of previous transmission attempts - it is extended only when a PPDU transmission fails, and reset to a smaller value when transmission succeeds. This dynamic behavior allows the system to maintain reliability by extending the window when needed while minimizing latency by keeping it small during successful transmission periods.
2Reliability
If a communication device waits for a long time before accessing the channel again after a failed PPDU, then collision probability is reduced, but productivity decreases due to delayed data delivery
Solution Approach 1:
The patent applies parameter changes by modifying the contention window size parameter based on transmission success or failure. When a PPDU transmission fails, the contention window parameter is increased to reduce collision probability in subsequent attempts. When transmission succeeds, the parameter is reset to a smaller value, enabling faster channel access and improving data delivery speed. This parameter adaptation resolves the contradiction between collision avoidance and productivity.
Data Source
AI summary
A communication device is configured to communicate with a second communication device, the communication device comprising circuitry configured to transmit one or more data frames to the second communication device that require a response by the second communication device, listen to a first response acknowledging receipt of at least one of the one or more data frames from the second communication device, and, if a first response is not received, change transmit opportunity configuration and/or channel access for non-data frames and/or data frames.