Interfering AP Beamforming for Overlapping WLAN Interference
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Solution Overview
Problem
In wireless local area networks (WLANs), overlapping basic service sets (BSSs) often experience interference due to limited frequency channels and a large number of BSSs, leading to performance deterioration in communication between stations (STAs) and access points (APs.
Innovation Solution
An interfering AP receives a beacon frame with interference avoidance information and a sounding physical layer convergence procedure (PLCP) protocol data unit (PPDU), determines a transmit steering matrix based on this data, and transmits data through a beam formed using this matrix to minimize interference between overlapping BSSs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple BSSs operate in overlapping service areas, then network coverage and capacity are improved, but interference between BSSs increases causing performance deterioration
Solution Approach 1:
The patent applies local quality by making different BSSs use different spatial characteristics through beamforming. Each AP transmits signals with directional beams tailored to its specific service area, creating localized transmission quality that reduces interference in overlapping regions while maintaining high capacity in each BSS.
Solution Approach 2:
The patent transitions from traditional omnidirectional or simple directional transmission to three-dimensional beamforming using multiple antennas. By adding spatial dimensionality through vertical and horizontal beam steering, the system can serve multiple BSSs in overlapping areas without interference, effectively increasing network capacity while managing interference through spatial separation.
2Object-affected harmful factors
If beamforming is used to reduce interference, then signal directionality is improved, but system complexity increases due to multiple antennas and processing requirements
Solution Approach 1:
The patent applies preliminary action by performing channel sounding and estimating channel state information (CSI) before actual data transmission. The AP sends sounding signals to STAs, receives feedback, and pre-calculates beamforming weights in advance. This preparation phase allows the system to reduce interference through beamforming without adding complex real-time processing during data transmission.
Solution Approach 2:
The patent uses channel state information (CSI) as an intermediary between the transmitted signal and the received signal. The CSI feedback from STAs to AP acts as a mediator that enables the AP to calculate appropriate beamforming weights, simplifying the overall system by decoupling the complex beamforming calculation from the data transmission process itself.
Data Source
AI summary
A method and a device for preventing interference in an overlapping service area are disclosed. The method for preventing interference in an overlapping service area of a wireless LAN can comprise the steps of: receiving, by an interference AP, a beacon frame broadcasted by an AP, wherein the beacon frame includes an interference prevention information element; receiving, by the interference AP, a sounding PPDU indicated on the basis of the interference prevention information element from the AP; determining, by the interference AP, a transmission control matrix on the basis of the sounding PPDU; and transmitting, by the interference AP, data through a beam generated on the basis of the transmission control matrix.