HEW Station UL MU-MIMO Receiver Gain Control
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Solution Overview
Problem
In high-density wireless network deployments, conventional IEEE 802.11 communications are less suitable for determining receiver gain in uplink multi-user multiple-input multiple-output (MU-MIMO) transmissions due to varying power levels and noise levels from multiple devices, leading to suboptimal performance.
Innovation Solution
The implementation of a short-training field (STF) design in high-efficiency wireless local area networks (HEW) that uses distinguishable STFs, allowing the master station to process and set receiver gain for improved uplink MU-MIMO performance by differentiating signals from each device, thereby determining a single automatic gain control (AGC) setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional IEEE 802.11 frame structure is used for uplink MU-MIMO transmissions, then multiple devices can transmit concurrently, but receiver gain determination becomes suboptimal due to varying power levels and noise levels from different devices
Solution Approach 1:
The patent applies preliminary action by implementing a short-training field (STF) design that enables the master station to determine receiver gain before the actual uplink MU-MIMO data transmission begins. The STF contains training sequences that allow advance measurement and calculation of receiver gain based on signal power and noise floor estimation, ensuring optimal gain settings are established prior to receiving transmissions from multiple devices with varying power levels
2Ease of operation
If receiver gain is set based on combined signals from multiple devices, then automatic gain control can be established, but signal clipping and quantization noise increase due to varying power levels from different devices
Solution Approach 1:
The patent applies partial action by having the master station determine receiver gain based on a representative subset of the received training sequences from multiple devices, rather than attempting to process all signals equally. The STF design allows the master station to identify and use training sequences from devices that provide reliable power level and noise floor measurements, establishing AGC settings that avoid clipping and quantization noise for the majority of transmissions without requiring perfect processing of every individual signal
Data Source
AI summary
Embodiments of a high-efficiency WLAN (HEW) master station and method for communicating in a Wireless Network are generally described herein. In some embodiments, the HEW master station comprises a receiver configured to receive an uplink multi-user multiple-input multiple-output (MU-MIMO) transmission from a plurality of scheduled HEW stations. The uplink MU-MIMO transmission may comprise at least an HEW short-training field (STF) (HEW-STF) transmitted by each of the scheduled HEW stations. The HEW-STFs received from the HEW stations are distinguishable. The master station may process the HEW-STFs received from the scheduled HEW stations to set receiver gain for reception of UL-MIMO data from the scheduled HEW stations. In some embodiments, a single automatic gain control (AGC) setting may be determined from the combined HEW-STF resulting in improved receiver performance in UL MU-MIMO.