MIMO Signal Transmission Using Cyclic Delay for Diversity and Multiplexing
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Solution Overview
Problem
Conventional multiple antenna technologies either achieve diversity gain or multiplexing gain but not both simultaneously, and require at least two transmit antennas to reduce data transmission rate.
Innovation Solution
A method and system that apply a cyclic delay of a different pattern to each symbol stream, converting their phase to ensure Δp,i−Δp-1,i>L and |det(D(k))| has a value of ‘1’, allowing for simultaneous diversity and multiplexing gains, and adjusting power levels to 1/√{NT}, enabling transmission via multiple antennas with NT symbol streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multiple antenna technologies are used to achieve diversity gain, then reliability is improved, but data transmission rate is reduced
Solution Approach 1:
The patent segments the transmission process into multiple independent symbol streams, each processed through separate cyclic delay chains. This segmentation allows parallel processing of multiple data streams while maintaining diversity through different delay patterns, thereby achieving both reliability improvement and high data transmission rate simultaneously
Solution Approach 2:
The patent introduces a time-delay dimension by applying cyclic delays to different symbol streams. This dimensional transformation allows the system to achieve diversity gain through temporal separation while maintaining spatial multiplexing through parallel transmission channels, resolving the contradiction between reliability and data rate
2Productivity
If conventional multiple antenna technologies are used to achieve multiplexing gain, then data transmission rate is increased, but reliability is reduced
Solution Approach 1:
The patent applies different cyclic delay patterns locally to each symbol stream before transmission. This local differentiation ensures that each transmitted stream has unique temporal characteristics, enabling the receiver to distinguish and correctly decode multiple simultaneous streams, thus maintaining both high data rate and error performance
Solution Approach 2:
The patent applies cyclic delays as a preliminary processing step to each symbol stream before transmission. This pre-processing ensures that the transmitted signals are already differentiated in the time domain, facilitating easier separation and decoding at the receiver, thereby maintaining reliability while achieving multiplexing gain
3Reliability
If at least two transmit antennas are used to reduce data transmission rate for diversity gain, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent creates a universal signal processing framework where cyclic delay diversity can be applied regardless of the number of transmit antennas. The same processing structure works for any antenna configuration, making the system versatile and avoiding the need for complex antenna-specific processing, thus improving reliability without proportionally increasing complexity
Data Source
AI summary
A method and apparatus for transmitting and/or receiving a signal in a multiple input multiple output (MIMO) system are provided. An apparatus for transmitting a signal in a multiple input multiple output (MIMO) system includes an input unit to receive NT symbol streams in parallel, where NT is an integer greater than or equal to 2, a multiple signal generating unit to generate NT multiple signals having a transmit diversity gain by applying a cyclic delay of a different pattern to each of the NT symbol streams, and a multiple signal providing unit to provide the generated NT multiple signals to NT transmit antennas, respectively, based on a predetermined transmit antenna index of each of the NT transmit antennas.