LTE-A CSI-RS Allocation in Last Half Symbols
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Solution Overview
Problem
In conventional CSI-RS transmission methods for LTE-A, the data part is punctured in RB/Sub-frames for transmitting CSI-RS, leading to deteriorated demodulation performance and reduced throughput for LTE user equipment.
Innovation Solution
A radio reception apparatus and method that acquire resource allocation information for a second reference signal (CSI-RS) in LTE-A, allowing the second reference signal to be transmitted in the last half symbols of a resource unit, minimizing resource interference with LTE user equipment and preventing throughput deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CSI-RS is transmitted in conventional RB/Sub-frames, then LTE-A channel quality measurement is enabled, but LTE user equipment demodulation performance deteriorates due to data part puncturing
Solution Approach 1:
The resource unit is divided into two parts: the first half for LTE data transmission and the second half for CSI-RS transmission. This segmentation allows LTE user equipment to demodulate data without interference from CSI-RS while enabling LTE-A user equipment to perform channel quality measurement using CSI-RS in the second half of the resource unit.
Solution Approach 2:
The patent introduces a time-domain dimension to resolve the conflict by allocating different time resources to different functions. The first half of the resource unit (in time) is dedicated to LTE data, while the second half is dedicated to CSI-RS, thereby separating the conflicting requirements in the time dimension.
2Quantity of substance
If CSI-RS is transmitted in conventional RB/Sub-frames, then LTE-A reference signal transmission is achieved, but system throughput decreases due to resource puncturing
Solution Approach 1:
The resource unit is segmented into two distinct time portions, with the first half allocated for data transmission and the second half for CSI-RS transmission. This segmentation ensures that reference signal transmission is achieved without puncturing data bits, thereby maintaining system throughput while enabling LTE-A functionality.
3Loss of information
If data is allocated from the beginning of the resource unit, then systematic bits are transmitted first, but CSI-RS transmission in conventional positions causes puncturing of systematic data bits
Solution Approach 1:
The patent extracts the CSI-RS transmission from the first half of the resource unit where data bits are located, and relocates it to the second half. This extraction eliminates the harmful puncturing effect on systematic data bits while preserving the integrity of the data transmission in the first half of the resource unit.
Data Source
AI summary
Where first and second reference signals for a first and second communication system, respectively, are transmitted, resources that affect a reception apparatus compatible only with the first communication system can be minimized, and the throughput can be prevented from being deteriorated. As resources for a reference signal CSI-RS for LTE-A, last half symbols in a time direction of a resource unit RB/Sub-frame defined in a frequency-time domain are used, and the CSI-RS is allocated in a position up to the last two symbols or in the last symbol, or the like, of a particular RB/Sub-frame and transmitted when a reference signal 4RS for LTE is transmitted to a reception apparatus in addition to transmitting CSI-RS for LTE-A. The reception apparatus receives CSI-RS allocated in the last half symbol of RB/Sub-frame based on CSI-RS allocation information, measures channel quality by using this CSI-RS, and transmits and reports feedback information.