Wireless Apparatus Direct Wave Detection for Reliable Transmission
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Solution Overview
Problem
Conventional wireless apparatuses experience communication disconnection when a shield is present in the line-of-sight due to sharp beam directivity, which affects high-speed and long-distance transmission reliability.
Innovation Solution
A wireless apparatus with multiple antennas that includes a direct wave detection unit using correlation coefficients to switch between beam forming and cyclic delay diversity, controlling cyclic shift units and beam forming to adapt transmission modes based on the presence or absence of a direct wave, ensuring reliable high-speed and long-distance transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If beam forming is used to enable high-speed and long-distance transmission, then transmission speed and distance are improved, but communication reliability deteriorates when a shield is present
Solution Approach 1:
The patent implements dynamic switching between beam forming and cyclic delay diversity modes based on the detection of direct wave presence. The system transitions from a static transmission mode to a dynamic one that adapts to environmental conditions (shield presence), thereby maintaining both high transmission performance and reliability. The beam forming unit and cyclic delay diversity unit are selectively activated based on real-time channel conditions.
Solution Approach 2:
The patent changes the transmission mode parameter (beam forming vs. cyclic delay diversity) based on detected channel conditions. When a direct wave is detected, beam forming parameters are applied for high-speed transmission; when no direct wave is detected, cyclic delay diversity parameters are applied for reliable transmission. This parameter adaptation resolves the contradiction between speed and reliability.
2Length of stationary object
If beam forming generates a narrow beam for long-distance transmission, then transmission distance is improved, but vulnerability to shields increases
Solution Approach 1:
The patent introduces a direct wave detection unit as an intermediary that monitors channel conditions and triggers mode switching. This intermediary detects the presence of direct waves (or their absence due to shields) and mediates the selection between beam forming and cyclic delay diversity, preventing shield-induced disconnections while maintaining long-distance capability.
Solution Approach 2:
The system performs preliminary detection of direct wave presence before executing the transmission. By detecting channel conditions in advance and pre-selecting the appropriate transmission mode (beam forming or cyclic delay diversity), the system avoids the harmful effect of shields on narrow beams while maintaining optimal transmission distance performance.
3Reliability
If cyclic delay diversity is used to improve reliability, then communication stability is improved, but transmission speed decreases
Solution Approach 1:
The patent dynamically selects between cyclic delay diversity and beam forming based on detected channel conditions. Cyclic delay diversity is activated only when direct waves are absent (shield present), while beam forming is used when direct waves are present. This dynamic selection ensures high reliability when needed and high speed when possible, resolving the speed-reliability trade-off.
4Productivity
If a narrow beam is generated for high-speed transmission, then transmission speed is improved, but disconnection risk increases when shields are present
Solution Approach 1:
The patent implements a feedback mechanism where the direct wave detection unit continuously monitors channel conditions and provides feedback to the transmission mode selector. Based on this feedback (presence or absence of direct waves), the system adjusts the transmission mode (beam forming or cyclic delay diversity), ensuring both high speed and connection stability by avoiding narrow beams when shields are detected.
Data Source
AI summary
A wireless apparatus is configured such that: a correlation calculation unit calculates a correlation coefficient for signals received from respective antennas; and a cyclic shift control unit compares the correlation coefficient with a threshold value. If the correlation coefficient is equal to or higher than the threshold value, the cyclic shift control unit determines that there is a direct wave, allocates a common shift amount to a cyclic shift unit, and causes a beam forming unit to form and transmit a narrow beam. Meanwhile, if the correlation coefficient is lower than the threshold value, the cyclic shift control unit determines that there is no direct wave, allocates different shift amounts to the cyclic shift unit, and causes the cyclic shift unit to diversify the cyclic shift.