MAC Layer Timing Modifications for Full-Duplex Channel Access
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Solution Overview
Problem
In 802.11 wireless networks, full-duplex nodes tend to monopolize the frequency channel unfairly due to their MAC layer design, which causes interference and prevents half-duplex nodes from accessing the channel, as they wait for extended interframe spaces (EIFS) after detecting errors from full-duplex communications.
Innovation Solution
Modifying the MAC layer to ensure that full-duplex nodes wait for an EIFS duration after communication, while half-duplex or non-full-duplex nodes wait for a shorter DIFS or SIFS duration, allowing them to initiate the next contention round promptly and reducing channel monopolization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex nodes use standard DIFS wait time after communication, then they can quickly re-access the channel, but they monopolize the frequency channel unfairly and prevent half-duplex nodes from accessing
Solution Approach 1:
The patent applies preliminary anti-action by having full-duplex nodes proactively wait for EIFS duration after successful communication. This pre-established longer wait time counteracts the tendency to monopolize the channel, allowing half-duplex nodes that experience errors to recover and access the channel fairly.
2Reliability
If half-duplex nodes wait for EIFS after detecting errors from full-duplex communications, then acknowledgment frames can be sent in time, but channel access efficiency decreases due to extended waiting
Solution Approach 1:
The patent changes the wait time parameter dynamically based on node type and communication mode. Full-duplex nodes wait for EIFS after successful communication to prevent monopolization, while half-duplex nodes wait for DIFS after successful communication. This parameter differentiation resolves the contradiction between reliable acknowledgment delivery and efficient channel access.
3Object-generated harmful factors
If all nodes in the network wait for EIFS after communication, then channel monopolization is reduced, but overall channel access efficiency decreases
Solution Approach 1:
The patent applies local quality by differentiating wait time behavior based on specific node characteristics and communication scenarios. Only full-duplex nodes that successfully complete communication wait for EIFS, while other nodes (half-duplex nodes, nodes experiencing errors, or nodes in different communication states) wait for appropriate shorter durations like DIFS. This localized application of the longer wait time prevents monopolization without unnecessarily reducing overall channel access efficiency.
Data Source
AI summary
A system, method, and computer-readable storage media for reducing monopolization of a frequency channel during full-duplex communications. The MAC layer of governing communications can be modified to reduce likelihood of monopolization by (1) in networks which are exclusively filled with full-duplex devices, configuring non-communicating devices to ignore data collisions of communicating devices, requiring the communicating devices to wait for an standard backoff time after the data transmission is complete; and/or (2) in mixed half-duplex/full-duplex networks, requiring a half-duplex nodes and/or a full-duplex node to wait an extended duration after the data transmission is complete, while the non-communicating devices do not wait an extended duration.