SIR-Based Yielding Protocol for 802.11 Spatial Reuse
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Solution Overview
Problem
Current 802.11 protocols are not optimized for spatial reuse in large-scale ad hoc networks, leading to conservative spatial reuse as they prevent simultaneous transmissions by devices within carrier sensing range, even for short links that can transmit without significant interference.
Innovation Solution
Implementing a Signal Interference Ratio (SIR) based yielding protocol that allows multiple devices to transmit during the same time interval by using transmission timing constraints and SIR-based decisions to minimize interference, enabling devices to proceed with communication if the interference will not affect the first pair of devices' transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carrier sensing protocol is used to prevent simultaneous transmissions, then transmission reliability is improved, but spatial reuse is reduced
Solution Approach 1:
The patent changes the parameter from binary carrier sensing (above/below threshold) to continuous SIR measurement and comparison against a threshold. This allows the system to distinguish between harmful interference and acceptable interference, enabling simultaneous transmissions when interference is low while maintaining reliability when interference is high.
Solution Approach 2:
The patent introduces dynamic yielding behavior where transmitters continuously monitor SIR and adjust their transmission status accordingly. The yielding decision is not static but dynamically adjusted based on real-time interference conditions, allowing the system to adapt to changing channel conditions and maximize spatial reuse while maintaining transmission reliability.
2Reliability
If conservative spatial reuse is implemented to avoid interference, then transmission integrity is improved, but network efficiency deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where receivers measure the SIR of incoming signals and provide yielding decisions back to transmitters. This feedback loop allows the system to learn from actual interference conditions and adjust transmission behavior accordingly, improving network efficiency while maintaining transmission integrity through informed yielding decisions.
Solution Approach 2:
The patent performs preliminary SIR measurement and yielding decision before actual data transmission. By evaluating interference conditions in advance (during the RTS/CTS exchange phase) and making yielding decisions beforehand, the system prevents harmful interference from occurring in the first place, thereby maintaining transmission integrity while allowing more concurrent transmissions to proceed.
3Device complexity
If static energy threshold is used for carrier sensing, then protocol simplicity is maintained, but adaptability to different link conditions is reduced
Solution Approach 1:
The patent changes the sensing parameter from static energy threshold to dynamic SIR measurement that adapts to different link conditions. The SIR threshold can be adjusted based on receiver capabilities, channel conditions, and traffic requirements, allowing the protocol to adapt to short links, long links, and various interference scenarios while maintaining reasonable implementation complexity.
Data Source
AI summary
Various embodiments are directed to changes in protocols, e.g., an enhanced 802.11 based protocol, that enables SIR based yielding and/or improves spatial reuse in networks, e.g., 802.11 based networks. Various methods and apparatus enable multiple devices using an 802.11 based protocol to communicate, e.g., transmit, during the same time interval. In various embodiments, the methods and apparatus use transmission timing constraints and/or Signal Interference Ratio (SIR) based yielding to avoid excessive interference between devices within communication range of each other.