MIMO Antenna Rate Request Signal Transmission
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Solution Overview
Problem
In MIMO systems, errors in rate information determined by the receiving apparatus can lead to deteriorated transmission quality and data rate, and existing methods consume excessive power, particularly when transmitting signals other than data such as rate request signals or training signals.
Innovation Solution
A radio apparatus that transmits data from multiple antennas, including a transmitter that sends a request signal with known signals from various antennas to improve data rate accuracy, and a selector that chooses the best antenna for data reception based on signal strength and quality, reducing power consumption by minimizing the number of antennas used for control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known signals are transmitted from all antennas including those not used for data transmission, then channel estimation accuracy is improved, but power consumption increases
Solution Approach 1:
The patent extracts only the necessary antennas for transmitting known signals. Specifically, only antennas that will be used for data transmission transmit known signals, while antennas not used for data transmission do not transmit known signals. This extraction principle resolves the contradiction by removing the unnecessary power consumption from antennas that don't need to transmit known signals.
Solution Approach 2:
The patent applies partial action by having only a subset of antennas (those used for data transmission) transmit known signals, rather than all antennas. This partial transmission is sufficient for achieving accurate channel estimation for the data-bearing antennas without the excessive power consumption of having all antennas transmit.
2Measurement precision
If rate information is transmitted periodically, then data rate accuracy is improved, but transmission overhead increases
Solution Approach 1:
The patent merges the rate request signal transmission with data transmission by embedding the rate request signal within the data stream. This combining approach allows rate information to be obtained accurately without requiring separate periodic transmissions, thereby reducing transmission overhead while maintaining data rate accuracy.
Solution Approach 2:
The patent performs preliminary action by having the receiving apparatus determine the data rate in advance based on channel estimation from known signals, and then the transmitting apparatus requests this predetermined rate information. This preliminary determination eliminates the need for continuous periodic rate information transmission, reducing overhead while maintaining accuracy.
3Productivity
If multiple antennas are used for data transmission, then data rate is improved, but system complexity increases
Solution Approach 1:
The patent segments the MIMO system into two functional parts: antennas that transmit known signals for channel estimation, and antennas that transmit data. This segmentation allows the system to manage complexity by clearly separating the estimation function from the data transmission function, enabling higher data rates through multiple antennas while maintaining manageable system complexity through functional separation.
Data Source
AI summary
A processing unit transmits, from at least one of a plurality of antennas, data corresponding respectively to the plurality of antennas. A control unit generates request signals with which to let a second radio apparatus supply information on rates at the second radio apparatus. When transmitting the request signal, the processing unit also transmits, from a plurality of antennas which includes antennas other than the antennas that transmit the data, known signals corresponding respectively to the plurality of antennas.