Dynamic CCA Backoff Mechanism for OBSS Interference Management
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Solution Overview
Problem
In wireless communication systems, overlapping basic service sets (OBSSs) can cause communication delays and disruptions due to interfering transmissions, as devices must abstain from transmitting when receiving packets with power above a certain threshold, leading to inefficiencies in channel usage.
Innovation Solution
A wireless device implements a backoff mechanism by increasing its transmission power threshold if it reduces its transmit power, allowing it to count down a backoff count during transmission opportunities and potentially increase transmission power after the interfering packet's transmission time has passed, thereby optimizing channel reuse and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a device abstains from transmitting when receiving packets with power above a certain threshold, then interference from overlapping basic service sets is avoided, but communication delays and channel usage efficiency deteriorate
Solution Approach 1:
The patent applies dynamics by making the transmit power threshold adjustable rather than fixed. The threshold is dynamically modified based on received signal strength measurements from overlapping BSS packets. When a device receives a packet with power above the threshold, it can adjust the threshold based on the received signal strength, allowing flexible adaptation to varying interference conditions while maintaining reliable communication
Solution Approach 2:
The patent changes the parameter of the power threshold based on received signal strength. By measuring the power of received packets from OBSS and adjusting the threshold accordingly, the system transforms a static parameter into a dynamic one that adapts to channel conditions, resolving the contradiction between avoiding interference and maintaining channel efficiency
2Loss of time
If a device reduces its transmit power to increase the threshold, then the threshold can be increased to allow backoff counting during transmission opportunities, but transmission power and signal strength deteriorate
Solution Approach 1:
The patent applies preliminary action by performing backoff counting during the transmission opportunity of the received packet rather than waiting for the transmission to complete. By counting down the backoff counter in advance during the TXOP, the device prepares for future transmissions without losing time, effectively compensating for the reduced transmit power
Solution Approach 2:
The patent maintains continuity of useful action by allowing the backoff counter to decrement continuously during the transmission opportunity even though transmit power is reduced. This ensures that the channel access mechanism remains active and productive throughout the transmission period rather than pausing, maintaining overall system efficiency
Data Source
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AI summary
A wireless first device may receive a packet from another device from an overlapping basic service set (OBSS). A received power of the packet may be greater than a threshold for transmitting during the time of the packet. If the first device reduces its transmit power, the first device may increase the threshold. If the received power is less than the increased threshold, the first device may count down a backoff count during a transmission time or transmission opportunity of the packet. In some cases, after the transmission time or transmission opportunity, the first device may increase its transmission power. In some cases, the condition for counting down a backoff count may also include initiating or finishing the transmission during the transmission time or the transmission opportunity of the packet, or transmitting at the reduced power.