Wi-Fi Access Point Interference Avoidance via Virtual NAV
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Solution Overview
Problem
The increasing interference between overlapping basic service sets (OBSSs) in Wi-Fi networks, particularly with the wider frequency bands used in 802.11ac, leads to inefficient frequency resource usage and significant overhead in network management due to the need for extensive information exchange and scheduling between access points.
Innovation Solution
An apparatus and method that determine the presence of adjacent access points, assess channel overlap, and control channel usage to either change to a non-overlapping channel or allocate a virtual network allocation vector (VNAV) section for shared channel use, minimizing interference and overhead by using a carrier sense multiple access/collision avoidance (CSMA/CA) protocol and message exchange between access points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the HCCA protocol is used to integrally manage transmission at an AP, then interference avoidance between OBSSs is achieved, but a large amount of information exchange and scheduling overhead is generated between adjacent APs
Solution Approach 1:
The patent extracts the essential function of interference avoidance from the complex HCCA protocol framework. Instead of implementing full HCCA-based integral management, the invention selectively applies only the necessary components (virtual NAV setting and selective transmission control) to achieve interference avoidance without the associated overhead of comprehensive scheduling and information exchange.
Solution Approach 2:
Each AP independently determines whether to set a virtual NAV based on its own transmission status and received signals from other APs. This self-service approach eliminates the need for centralized scheduling and extensive information exchange between APs, as each AP autonomously makes decisions to avoid interference while maintaining its own transmission opportunities.
2Productivity
If wider frequency bands (20 MHz, 40 MHz, 80 MHz, 160 MHz) are used in 802.11ac, then data transmission capacity is improved, but the probability of channel overlap between adjacent APs increases
Solution Approach 1:
The patent implements periodic transmission opportunities for APs using virtual NAV settings. By allocating specific time periods during which each AP can transmit without interference from neighboring APs, the system enables wider frequency band utilization while preventing channel overlap interference through time-division multiplexing of transmission rights.
3Productivity
If channel sharing between OBSSs is implemented, then frequency resource efficiency is improved, but interference management complexity increases
Solution Approach 1:
The virtual NAV (Network Allocation Vector) serves as an intermediary mechanism that simplifies interference management in shared channels. Instead of complex real-time coordination between APs, each AP sets a virtual NAV value that acts as a time-based permit, allowing other APs to know when it is safe to transmit. This intermediary approach enables efficient frequency sharing while reducing interference management complexity to simple timer-based control.
Data Source
AI summary
The present invention relates to an apparatus and a method for avoiding signal interference between access points (APs) in a non-license band, and more particularly, an interference avoidance apparatus and method between access points (APs) that avoid interference based on whether an overlapping basic service set (OBSS) is present, whether an overlapping operation channel between adjacent APs is used, whether it is possible to select a non-overlapping operation channel between adjacent APs, and the like.