Cyclic Shift Diversity for Wireless Uplink Interference
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Solution Overview
Problem
Wireless communications with simultaneous transmissions from multiple devices experience communication artifacts due to multipath fading and destructive interference from common content superposition in frequency and time, particularly in indoor environments.
Innovation Solution
Implementing cyclic shift diversity (CSD) in uplink transmissions to adjust the arrival times of signals from different antennas, using predefined or dynamically assigned CSD values to enhance reliability and resilience, especially in multi-user scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple devices transmit common content simultaneously in uplink, then communication throughput and efficiency are improved, but communication artifacts occur due to multipath fading and destructive interference
Solution Approach 1:
The patent applies cyclic shift diversity by changing the time domain parameter of the transmitted signal. Specifically, different spatial streams apply different cyclic shifts (time delays) to their common content, transforming the arrival times of signals from different antennas. This parameter change prevents simultaneous constructive/destructive interference while maintaining simultaneous transmission capability, thus resolving the contradiction between throughput and reliability
2Reliability
If cyclic shift diversity is applied to adjust signal arrival times, then reliability and resilience are enhanced, but signal timing synchronization becomes more complex
Solution Approach 1:
The patent implements cyclic shift diversity by pre-adjusting the timing of signals before transmission. The cyclic shift values are determined in advance based on the number of spatial streams, and the timing adjustment is applied during signal generation rather than requiring complex real-time processing at the receiver. This preliminary action simplifies the overall system complexity while maintaining reliability benefits
Data Source
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AI summary
Cyclic shift diversity (CSD) for the simultaneous wireless transmissions, such as uplink transmissions, from the antennas of multiple communication devices is provided.