User Terminal Reference Signal Mapping for Overhead Reduction
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Solution Overview
Problem
In a single carrier transmission system, the overhead increases when a reference signal is transmitted for each user due to the use of an antenna port common between the physical control channel/physical data channel, necessitating effective mapping of reference signals.
Innovation Solution
A user terminal and radio communication method that includes a reception section for receiving downlink signals, a channel estimation section for performing channel estimation using reference signals, and a demodulation and decoding section that maps and decodes downlink control and data signals, where the reference signals are mapped in the time domain, with at least one reference signal common to multiple users, allowing demodulation and decoding based on channel estimation results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference signal is transmitted for each user using an antenna port common between physical control channel/physical data channel, then demodulation accuracy is improved, but overhead increases
Solution Approach 1:
The patent applies universality by using a common antenna port for multiple purposes: transmitting both the physical control channel/physical data channel and the reference signal. This allows the same antenna port to serve multiple functions, reducing the need for separate dedicated ports and thereby reducing overhead while maintaining demodulation capability
Solution Approach 2:
The patent merges the reference signal transmission with the existing antenna port structure used for control and data channels. By combining these functions into a common antenna port framework, the system reduces the total number of separate transmission resources needed, thus reducing overhead while preserving the ability to perform accurate channel estimation and demodulation
2Loss of energy
If reference signals are mapped in time domain for single carrier transmission, then PAPR is reduced, but mapping complexity increases
Solution Approach 1:
The patent changes the mapping domain parameter from frequency domain to time domain for reference signals in single carrier transmission. This parameter change enables the system to achieve lower PAPR characteristics while the patent simultaneously provides specific mapping rules and patterns to manage the complexity introduced by time-domain mapping
3Object-affected harmful factors
If directional transmission using antenna port common between reference signal and physical channel is performed, then interference is reduced, but overhead increases
Solution Approach 1:
The patent applies universality by configuring the antenna port to serve multiple functions simultaneously: it enables directional transmission for interference reduction while also serving as the common port for reference signal and physical channel transmission. This multi-functionality reduces overhead by eliminating the need for separate dedicated ports
Solution Approach 2:
The patent applies local quality by applying directional transmission (precoding) specifically to the antenna port configuration for reference signals and physical channels. This localized application of beamforming technology provides interference reduction in specific spatial directions while maintaining system-wide compatibility and reducing overall overhead
Data Source
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AI summary
A first reference signal which is referred to during demodulation of a physical control channel, and a second reference signal which is referred to during demodulation of a physical data channel are mapped in time domains in the downlink signal. The first reference signal and/or the second reference signal are/is shared by a plurality of user terminals. A demodulation/decoding unit (110) of a user terminal (20) uses a channel estimation result based on the first reference signal to demodulate and decode a physical control channel addressed to the host device. Furthermore, the demodulation/decoding unit (110) uses a downlink control signal addressed to the host device, and a channel estimation result based on the second reference signal, to demodulate and decode a physical data channel addressed to the host device.