Burst Receiver AGC for Beamformed MIMO Gain Accuracy
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Solution Overview
Problem
In MIMO systems, the difference in gain determined by known signals for Legacy and MIMO systems leads to errors when beamforming is performed, especially due to the shorter interval of MIMO known signals, causing signal saturation and increased gain errors.
Innovation Solution
A receiving apparatus that assigns a first known signal in the header portion and a second known signal posterior to it, with a decision unit determining a tentative gain in the first signal, reducing it, and using the reduced tentative gain as an initial value to determine the gain for the second signal, thereby reducing errors and preventing signal saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the period of known signal in beamformed signals is shortened to accommodate MIMO system requirements, then the data transmission rate is improved, but the error in gain determination becomes larger
Solution Approach 1:
The patent applies preliminary action by determining a tentative gain value before the actual gain determination process. The decision unit first calculates a preliminary gain based on the received signal strength indicator (RSSI) of the known signal, then uses this tentative value as a reference to determine the final gain. This preliminary calculation provides a head start that compensates for the shortened known signal period, allowing accurate gain determination even when the signal duration is reduced for higher data transmission rates.
2Productivity
If beamforming is performed on MIMO signals to improve directional transmission, then the data transmission rate is improved, but signal saturation occurs and gain errors increase
Solution Approach 1:
The patent applies partial action by using only a portion of the tentative gain value in the final gain determination. Specifically, the decision unit determines the final gain by combining the tentative gain with additional adjustments based on signal characteristics, rather than using the full tentative gain value directly. This partial utilization prevents over-amplification and signal saturation while still benefiting from the directional enhancement provided by beamforming, thus maintaining both high data transmission rates and signal processing accuracy.
Data Source
AI summary
Burst signals are received. An AGC unit determines gain for the received burst signal. A VGA unit amplifies the received burst signal by the determined gain. In the burst signal, Legacy STS is assigned in a header portion and MIMO-STS is assigned posterior to the Legacy STS. The AGC unit determines a tentative gain in Legacy STS. The tentative gain is then reduced. With the reduced tentative gain as an initial value, the gain is determined in MIMO-STS.