SDM Transmitter Channel Stability Control
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Solution Overview
Problem
Conventional SDM communication systems face inefficiencies due to incorrect determinations in directivity control, leading to decreased transmission efficiency, especially when channel fluctuations occur, and complex calculations at the transmitting end cause processing delays.
Innovation Solution
A transmitting/receiving apparatus that performs channel estimation, determines correlation between channel values, and adjusts transmission weights accordingly to enable or disable directivity control based on channel stability, ensuring correct SDM communication and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If directivity control is performed using channel estimation at the transmitting end, then communication capacity is increased, but processing delay increases due to complex calculations
Solution Approach 1:
The system performs channel estimation at the receiving end in advance and stores the results. When transmission occurs, the pre-stored channel estimation data is immediately available, eliminating the need for time-consuming calculations at the transmitting end and reducing processing delay while maintaining communication capacity.
Solution Approach 2:
The receiving end performs channel estimation and feeds back the results to the transmitting end. This feedback mechanism allows the transmitting end to obtain channel information without performing complex calculations itself, thus increasing communication capacity while avoiding processing delays.
2Reliability
If directivity control is performed using channel estimation at the transmitting end, then spatial orthogonal channels are formed, but error rate performance deteriorates when channel fluctuation is large
Solution Approach 1:
The system dynamically determines whether to perform directivity control based on channel correlation between consecutive time slots. When channel conditions are stable (high correlation), directivity control is applied to form spatial orthogonal channels. When channel conditions change rapidly (low correlation), directivity control is suspended to avoid error rate deterioration, thus adapting to varying channel conditions.
Solution Approach 2:
The system changes the operational parameter of directivity control (on/off state) based on channel correlation threshold comparison. This parameter change allows the system to switch between directivity control and non-directivity control modes, optimizing error rate performance under different channel fluctuation conditions.
3Productivity
If directivity control is performed without proper channel stability determination, then transmission efficiency decreases, but system complexity increases
Solution Approach 1:
Instead of performing directivity control in all conditions, the system applies it only when channel correlation exceeds a predetermined threshold. This partial action approach maintains transmission efficiency by applying directivity control only when beneficial, while avoiding the excessive complexity of implementing it unconditionally.
Solution Approach 2:
The system performs preliminary channel correlation determination before deciding whether to apply directivity control. This preliminary check simplifies the overall system by avoiding unnecessary directivity control operations, thereby maintaining transmission efficiency without increasing system complexity.
Data Source
AI summary
A transmitting/receiving apparatus wherein a decision of performing SDM communication accompanied by a directivity control is correctly performed to improve the transmission efficiency. In the apparatus, a channel estimating part (205) performs channel estimation by use of known symbols included in a received signal. A channel variation deciding part (206) determines a correlation value between a channel estimation result of an immediately preceding process and that of a current process to determines the magnitude of a channel variation, and the determines, based on the magnitude of the channel variation, whether to perform SDM communication accompanied by a directivity control of perform SDM communication not accompanied by the directivity control. When a radio receiving part (107) receives a transmitting weight, a switching part (108) outputs the received transmitting weight to multipliers (103-1 to 103-n). When the receiving part (107) receives a signal an instruction of performing SDM communication not accompanied by the directivity control, the switching part (108) outputs, as the transmitting weight, “1” indicative of performing no directivity control, to the multipliers (103-1 to 103-n).