Access Point Transmission Power Control for Uplink Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-user transmission (MU) with random access in IEEE 802.11ax, the access point struggles to determine appropriate transmission power for stations, leading to increased reception power differences and interference, which can exceed the dynamic range of A/D conversion and reduce Signal to Interference plus Noise Ratio (SINR).
Innovation Solution
The access point dynamically controls transmission power by including target reception power values in random access control signals, allowing stations to adjust their power based on path-loss estimation and beam forming, ensuring reception power falls within a predetermined range, thereby reducing interference and maintaining A/D conversion dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If random access resource allocation is used in UL MU transmission, then station access flexibility is improved, but reception power difference between stations increases
Solution Approach 1:
The access point performs preliminary path-loss estimation for each station before the actual uplink transmission. This preliminary action allows the access point to predict the reception power of each station's uplink signal and calculate appropriate target reception power values in advance, which are then included in the trigger frame to guide station transmission power adjustment.
Solution Approach 2:
The access point provides feedback to stations about their estimated path-loss and target reception power values through the trigger frame. This feedback mechanism enables stations to adjust their transmission power accordingly, ensuring that reception power differences between stations are reduced while maintaining random access flexibility.
2Reliability
If transmission power is increased to ensure reception quality, then Signal to Interference plus Noise Ratio is improved, but interference between stations increases
Solution Approach 1:
The access point calculates individualized target reception power values for each station based on their specific path-loss conditions. This local quality approach ensures that each station transmits at the appropriate power level for its specific location and channel conditions, rather than using a uniform high power level for all stations, thereby maintaining reception quality while reducing unnecessary interference.
3Manufacturing precision
If target reception power values are individually set for each station, then reception power uniformity is improved, but control signal complexity increases
Solution Approach 1:
The access point merges multiple pieces of control information including path-loss estimation results, target reception power values, and resource allocation information into a single trigger frame. This merging approach allows individualized power control for each station while using a unified control signal structure, avoiding the need for separate control messages for each station and thus limiting the increase in control signal complexity.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A communication device of the present disclosure includes: a target reception power setting unit that sets at least one target reception power value as UL transmission power control information for controlling upstream transmission power of each of multiple stations, the target reception power value being a target value of reception power when an upstream signal is received from each of the multiple stations; a signal generating unit that generates a random access control signal including the at least one target reception power value; and a transmitting unit that transmits the random access control signal.