Phase Shift Precoding for Multi-Antenna Systems
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Solution Overview
Problem
Conventional phase shift diversity and precoding schemes in multi-antenna systems face limitations, such as restricted spatial multiplexing rates and inefficiency in high mobile speeds due to rapid channel changes, which hinder achieving full system throughput and reliability.
Innovation Solution
A Phase Shift Based Precoding method using a unitary matrix is introduced, allowing for optimized communication by selecting or transforming the precoding matrix based on communication situations, including the use of a phase shift based precoding matrix that applies uniformly increasing or decreasing cyclic delay values to each antenna, and a generalized phase shift diversity scheme that converts flat fading channels to frequency selectivity channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional phase shift diversity or precoding schemes are used, then spatial multiplexing rate is restricted, but communication efficiency and channel capacity are limited
Solution Approach 1:
The patent applies dynamics by making the precoding matrix time-varying through cyclic delay accumulation. The phase shift values change over time according to a cumulative pattern, allowing the system to adapt to time-varying channels without requiring feedback information, thereby achieving both high spatial multiplexing rate and communication efficiency
Solution Approach 2:
The patent changes the parameter of phase shift values dynamically. By accumulating cyclic delays and transforming the precoding matrix based on time-varying phase shifts, the system achieves frequency diversity gain while maintaining high spatial multiplexing capability, resolving the contradiction between productivity and reliability
2Reliability
If feedback information is used for precoding, then signal to noise ratio is maximized, but the system becomes ineffective in high mobile speeds due to rapid channel changes
Solution Approach 1:
The system performs self-service by generating its own adaptive precoding matrices through cyclic delay accumulation without external feedback. The time-varying channel characteristics are exploited directly to create the precoding pattern, eliminating the need for feedback information and enabling effective operation in high mobile speed scenarios
Solution Approach 2:
The patent applies preliminary action by pre-establishing the cyclic delay accumulation pattern before actual transmission. The phase shift values are generated in advance based on the cumulative delay pattern, allowing the system to adapt to rapid channel changes without requiring real-time feedback, thus maintaining reliability in high mobility environments
3Reliability
If cyclic delay diversity is applied, then frequency diversity gain is obtained, but spatial multiplexing rate is restricted to 1
Solution Approach 1:
The patent merges cyclic delay diversity with spatial multiplexing by combining the frequency diversity effect of cyclic delays with the spatial multiplexing capability of multiple antennas. The precoding matrix incorporates both temporal (cyclic delay) and spatial (multiple antenna) dimensions, achieving frequency diversity gain while maintaining spatial multiplexing rate greater than 1
Solution Approach 2:
The patent adds another dimension by introducing time-varying phase shifts into the spatial multiplexing framework. The cyclic delay accumulation creates a temporal dimension that interacts with the spatial dimension of multiple antennas, enabling simultaneous frequency diversity gain and high spatial multiplexing rate through the combined precoding operation
Data Source
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AI summary
A method of transmitting data using phase-shift-based precoding in a multiple antenna system using a plurality of subcarriers and a transceiver for implementing said method are disclosed. More specifically, the method includes determining a phase-shift-based precoding matrix (540) for transmitting the data by adjusting a transmission phase angle for each antenna, applying an offset for applying offset information fed back from a receiving terminal to the determined precoding matrix (540), and performing precoding by multiplying the offset applied precoding matrix (540) by a symbol of each subcarrier.