LTE Uplink Control Signal Reception via SC-FDMA Symbol Segmentation
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Solution Overview
Problem
In LTE systems, spatial multiplexing transmission in uplink data signals complicates the reception of control signals, leading to processing delays and reduced quality due to interference from data signals, necessitating a method to receive control signals with high quality and efficiency.
Innovation Solution
A mobile terminal apparatus and radio base station apparatus are configured to separate data and control signals into different radio resources and perform MIMO transmission based on precoding information, allowing for efficient reception of control signals by canceling interference through time-multiplexing on an SC-FDMA symbol basis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial multiplexing transmission is applied to uplink data signals to improve spectral efficiency, then spectral efficiency increases, but control signal reception quality deteriorates due to interference from data signals
Solution Approach 1:
The patent segments the uplink transmission by separating control signals and data signals into different SC-FDMA symbols within the same subframe. This segmentation allows spatial multiplexing to be applied to data signals while control signals are transmitted in dedicated symbols without interference, thus maintaining control signal reception quality while improving overall spectral efficiency.
Solution Approach 2:
The patent introduces a precoding mechanism as an intermediary process. The precoder uses channel state information to optimize the transmission of spatial multiplexed data signals, thereby reducing their interference impact on control signals. This intermediary processing enables the system to achieve high spectral efficiency while protecting control signal integrity.
2Productivity
If control signals and data signals are transmitted simultaneously in the same subframe, then transmission efficiency improves, but processing complexity increases at the base station
Solution Approach 1:
The patent segments the uplink subframe into different SC-FDMA symbols, with specific symbols dedicated to control signals and others to data signals. This segmentation simplifies base station processing by allowing separate handling of control and data channels, reducing the complexity of simultaneous reception while maintaining high transmission efficiency.
Solution Approach 2:
The patent applies different transmission qualities to different signal types within the same subframe. Control signals are transmitted with dedicated resources and optimized parameters in specific symbols, while data signals use spatial multiplexing in other symbols. This local differentiation reduces overall processing complexity while maintaining efficiency.
3Loss of energy
If control signals are time-multiplexed with data signals in a single SC-FDMA symbol to achieve low PAPR, then power ratio performance improves, but control signal reception quality deteriorates due to interference
Solution Approach 1:
The patent segments the transmission into multiple SC-FDMA symbols, dedicating specific symbols to control signals and others to data signals. This eliminates the interference problem of time-multiplexing within a single symbol while maintaining low PAPR benefits across the overall transmission structure.
Solution Approach 2:
The patent moves the control-data separation from the time dimension (within a single symbol) to the symbol dimension (different symbols within a subframe). This dimensional change allows both control and data signals to be transmitted simultaneously in the same subframe without mutual interference, achieving both low PAPR and high reception quality.
Data Source
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AI summary
To provide a radio communication method for enabling a control signal to be received with high quality and high efficiency, in the case of using spatial multiplexing transmission in data signals to transmit, and also transmitting the control signal in the same sub-frame, in the radio communication method of the invention, a mobile terminal apparatus receives a downlink signal including precoding information, separates a data signal and a control signal to assign to different radio resources, and performs MIMO-transmission on a signal of each transmission layer based on the precoding information, and a radio base station apparatus receives an uplink signal including the data signal and the control signal subjected to MIMO transmission, divides the uplink signal into data signals for each transmission layer, and reproduces the control signal from the uplink signal.