Wireless Transmitter Phase Rotation for Channel-Aware Antenna Delay
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Solution Overview
Problem
Conventional communication systems fail to achieve an adequate multi-user diversity effect due to limitations in allocated slot and receiver location.
Innovation Solution
A wireless transmitter with multiple antennas and a phase rotating unit that applies phase rotation to control the maximum delay time between antennas, allowing for improved channel estimation and selection of optimal base station antennas to enhance communication state, thereby achieving a favorable multi-user diversity effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blocks which are wide in the frequency direction are allocated to obtain frequency diversity effect, then error rate is reduced with low receiving power, but multi-user diversity effect cannot be obtained
Solution Approach 1:
The patent applies different phase rotation strategies to different antennas based on channel conditions. Specifically, it identifies which antennas experience fading and applies phase rotation only to those antennas, while leaving other antennas unchanged. This localized application of phase rotation allows the system to maintain frequency diversity benefits while simultaneously enabling multi-user diversity through selective antenna transmission.
Solution Approach 2:
The patent dynamically adjusts the transmission strategy by determining channel conditions for each antenna and user, then adaptively selecting which antennas to apply phase rotation to and which users to serve. This dynamic adaptation allows the system to switch between frequency diversity and multi-user diversity modes based on real-time channel conditions, resolving the contradiction between reliability and productivity.
2Productivity
If blocks which are narrow in the frequency direction are allocated to obtain multi-user diversity effect, then user-specific communication efficiency is improved, but frequency diversity effect is reduced
Solution Approach 1:
The patent merges frequency diversity and multi-user diversity techniques by combining wide frequency blocks with selective phase rotation application. Instead of choosing one approach over the other, it integrates both by transmitting to multiple users across wide frequency blocks while applying phase rotation selectively to maintain both diversity effects simultaneously.
3Measurement precision
If phase rotation is applied to control maximum delay time between antennas, then channel estimation accuracy is improved, but system complexity increases
Solution Approach 1:
The patent changes the phase rotation parameter dynamically based on channel conditions rather than using a fixed phase rotation scheme. By adjusting the phase rotation amount according to which antennas are experiencing fading and which users are being served, the system improves channel estimation accuracy while managing complexity through adaptive rather than exhaustive parameter adjustment.
Data Source
AI summary
A wireless transmitter includes: a plurality of transmission antennas; and a phase rotating unit which adds phase rotation to signals which are respectively input to the plurality of transmission antennas, wherein the phase rotating units adds first phase rotation for controlling the maximum delay time between the plurality of transmission antennas and second phase rotation for controlling the phases of arbitrary antennas among the plurality of transmission antennas.