Central Terminal Antenna Selection for MIMO Signal Adaptation
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Solution Overview
Problem
Current MIMO-based wireless transmission systems, especially those adhering to the 802.11n standard, face challenges in adapting to changing environmental conditions in domestic environments due to the lack of a return channel, leading to inefficiencies in signal transmission and increased complexity, energy consumption, and costs in implementing beamforming techniques.
Innovation Solution
A MIMO system with a central terminal and client terminals is combined with a network of directive antennas and a pseudo return channel to gather environmental information, allowing the central terminal to adjust its antenna selection based on reception quality feedback, using RFID sensors and a measurement circuit to determine channel variations and optimize signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming technique is implemented to improve transmission capacity and resistance to interferences, then transmission performance is improved, but device complexity and implementation cost increase significantly
Solution Approach 1:
The patent implements a feedback mechanism where the receiver measures the channel state information (CSI) and sends it back to the transmitter through a return channel. This feedback enables the transmitter to adapt its beamforming strategy based on actual channel conditions, achieving reliable transmission performance without requiring complex real-time processing at the transmitter side.
Solution Approach 2:
The patent performs channel state information measurement and processing in advance at the receiver side before transmission. By pre-calculating the optimal beamforming weights based on received CSI and storing them, the system avoids complex real-time computations during actual data transmission, thereby reducing implementation complexity while maintaining transmission performance.
2Adaptability or versatility
If a return channel is added to enable beamforming adaptation, then transmission adaptability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a return channel that feeds back channel state information from the receiver to the transmitter. This feedback mechanism enables the transmitter to adapt its beamforming transmission strategy according to actual channel conditions, achieving transmission adaptability without requiring complex bidirectional communication protocols.
Solution Approach 2:
The patent uses channel state information (CSI) as an intermediary carrier to transmit adaptation data from the receiver to the transmitter. Instead of implementing complex direct communication between terminals for adaptation, the CSI serves as a simplified mediator that conveys necessary channel information, reducing system complexity while enabling adaptability.
3Productivity
If spatial multiplexing is used to increase transmission capacity, then bitrate is improved, but robustness in difficult transmission conditions deteriorates
Solution Approach 1:
The patent dynamically switches between spatial multiplexing mode (for high transmission capacity in good conditions) and beamforming mode (for high robustness in difficult conditions) based on channel state information. This dynamic adaptation allows the system to optimize the trade-off between transmission capacity and robustness according to actual environmental conditions.
Solution Approach 2:
The patent changes the transmission parameters (specifically the beamforming weights and spatial multiplexing configuration) based on channel state information. By adjusting these parameters according to channel quality, the system achieves high transmission capacity when conditions are good and maintains robustness when conditions are difficult, resolving the contradiction between productivity and reliability.
Data Source
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AI summary
The present invention relates to a central terminal for a wireless transmission system for signals intended more specifically for a domestic environment. - The central terminal (1) comprises at least m transmission channels (11) and n directive transmission antennas (12) intended to transmit first signals (S1), with n>m>1, switching means (13) in order to associate with each signal transmission channel one antenna from among the n antennas according to a switching schema selected by control means (14), a transmission circuit (15) able to transmit via at least one of the directive antennas selected for said client terminal, a second signal (S2, S3) called the interrogation signal in a frequency band close to or identical to the predetermined frequency band of the transmission channel, the control means (14) being connected to a return channel transmitting at least one item of information on the reception quality of the signals transmitted by said central terminal, said control means selecting a switching schema according to said at least one item of information.