Phase Shift Precoding for Wireless Interference Reduction
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Solution Overview
Problem
In wireless communication systems, existing methods face challenges in efficiently transmitting data using multiple antennas due to interference between users and high feedback overhead, particularly in multi-user scenarios, which affects transmission efficiency and increases the possibility of errors.
Innovation Solution
A phase shift-based precoding method is employed, where feedback information from mobile stations is used to determine a precoding matrix that increases the phase angle of user data, allowing for independent channel encoding and modulation on each antenna, thereby minimizing interference and optimizing transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transmit diversity schemes (PARC, PU2RC) are used with multiple antennas, then system capacity and link reliability are improved, but interference between users occurs and transmission efficiency is affected
Solution Approach 1:
The patent applies phase shift-based precoding that changes the phase parameter of transmitted signals across different antennas. By adjusting phase angles dynamically, the system directs signal energy toward intended users while suppressing interference to other users, thus maintaining reliability while reducing harmful interference effects.
Solution Approach 2:
The precoding matrix acts as an intermediary between the data streams and the multiple transmit antennas. It processes the data before transmission, applying phase shifts that mediate the interaction between multiple users sharing the same channel, thereby reducing interference while maintaining system capacity.
2Productivity
If feedback information size is increased to improve transmission optimization, then transmission efficiency is improved, but the possibility of transmission error increases
Solution Approach 1:
The patent extracts only the essential phase shift information from the full channel state information for feedback purposes. Instead of transmitting complete channel matrices, the system identifies and feeds back only the critical phase parameters needed for precoding, thereby reducing feedback overhead while maintaining transmission efficiency.
Solution Approach 2:
The feedback mechanism focuses on local quality by transmitting only the specific phase shift parameters that are most critical for precoding optimization, rather than providing complete global channel information. This selective feedback approach reduces error probability while preserving the ability to optimize transmission efficiency.
3Productivity
If phase shift-based precoding is applied to increase phase angle of user data, then channel capacity loss is reduced and transmission efficiency is enhanced, but device complexity increases
Solution Approach 1:
The system changes the phase parameter of transmitted signals in a controlled manner using predefined phase shift patterns. This parameter-based approach simplifies the precoding implementation compared to full matrix operations, as it requires only phase angle adjustments rather than complex amplitude and phase manipulations across all antenna elements.
Data Source
AI summary
According to one embodiment, a method of receiving signals from a transmitter having a plurality of antennas includes: receiving the signals from the transmitter; selecting a precoding matrix based on a multiplexing rate (R) by selecting R column vectors from a single matrix corresponding to a maximum multiplexing rate, wherein the maximum multiplexing rate corresponds to a number (Nt) of the plurality of antennas, wherein each column vector of a first precoding matrix corresponding to a first multiplexing rate is included as a part of column vectors of a second precoding matrix corresponding to a second multiplexing rate when the second multiplexing rate is greater than the first multiplexing rate; and processing the received signals using the selected precoding matrix.