Trigger Frame Interference Coordination in Dense Wireless Networks
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Solution Overview
Problem
In densely populated network environments, especially where multiple wireless base stations (APs) coexist, mutual interference occurs, reducing communication efficiency and frequency utilization, particularly in downlink communication, where transmission demand is higher.
Innovation Solution
A communication apparatus and method that utilize a control section to send a trigger frame to induce a transmission refrainment frame, determining transmission power to reach interference sources, thereby reducing interference by coordinating schedules and controlling transmission power, especially between non-cooperative APs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple wireless base stations (APs) are installed in densely populated network environments, then wireless connection coverage is improved, but mutual interference between networks increases
Solution Approach 1:
The system sends a trigger frame before actual data transmission to induce terminal devices to perform clear channel assessment (CCA) and refrain from transmitting during the upcoming transmission period. This preliminary action prevents interference before it occurs, allowing multiple APs to coexist in densely populated environments while maintaining network coverage.
Solution Approach 2:
The trigger frame acts as an intermediary signal that coordinates transmission behavior between multiple APs and their associated terminal devices. By using this intermediary mechanism, the system enables non-cooperative APs to avoid mutual interference without requiring direct cooperation protocols, thus resolving the contradiction between coverage expansion and interference reduction.
2Area of stationary object
If transmission power is increased to extend coverage, then network coverage area is improved, but interference to other networks increases
Solution Approach 1:
The system determines transmission power parameters specifically for the trigger frame to ensure it reaches interference source terminal devices at appropriate power levels. This localized power control allows the AP to maintain coverage while minimizing excessive interference, as the trigger frame is transmitted with optimized power rather than maximum power used for all communications.
3Object-affected harmful factors
If trigger frame is sent ahead of data frame transmission, then interference avoidance is improved, but transmission overhead increases
Solution Approach 1:
The trigger frame mechanism applies partial action by only inducing CCA and transmission refrainment at terminal devices that are potential interference sources, rather than requiring all devices to refrain. This selective approach provides sufficient interference avoidance while minimizing the overhead associated with the trigger frame mechanism.
Data Source
AI summary
A communication apparatus and a communication method that avoid mutual interference between nodes. The communication apparatus includes a communication section and a control section. The communication section sends and receives wireless frames. The control section controls transmission and reception of frames. The control section controls transmission, to one or more target stations and with a transmission parameter (transmission power) specified for each target station, of a trigger frame that induces transmission of a transmission refrainment frame. The communication apparatus functions as a base station, and the control section selects, as target stations, one or more subordinate terminals to which a downlink signal is to be sent and controls the transmission of the trigger frame ahead of the transmission of the downlink signal.