Uplink Demodulation Reference Signal Configuration for Multi-Antenna Transmission
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Solution Overview
Problem
Current LTE radio access technologies face challenges in uplink transmission efficiency due to limitations in power amplifier efficiency and antenna arrangement, which hinder the implementation of spatial multiplexing using Multiple-Input Multiple-Output (MIMO) techniques, essential for maximizing frequency resource utilization and achieving high-speed communication.
Innovation Solution
A method and apparatus for configuring and transmitting demodulation reference signals (DMRS) using multiple antennas in a radio communication system, allowing for multi-antenna transmission modes based on configuration information received from the base station, enabling efficient uplink channel transmission through Orthogonal Space Resource Transmission (OSRT) schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial multiplexing using MIMO is implemented in uplink transmission, then frequency resource utilization and communication speed are improved, but power amplifier efficiency and antenna arrangement become limiting factors
Solution Approach 1:
The patent segments the uplink transmission by introducing separate demodulation reference signals for each transmission layer. This allows the system to support spatial multiplexing with multiple layers while maintaining compatibility with existing single-antenna transmission mechanisms, thereby improving frequency resource utilization without completely overhauling the power amplifier system.
Solution Approach 2:
The patent extends the reference signal design from the time-frequency domain to include the spatial dimension by introducing layer-specific reference signals. This dimensional extension enables the system to support multiple transmission layers simultaneously, achieving spatial multiplexing gain while managing power amplifier constraints through proper reference signal placement.
2Speed
If spatial multiplexing using MIMO is implemented in uplink transmission, then communication speed is improved, but antenna arrangement becomes a limiting factor
Solution Approach 1:
The patent segments the reference signal resources by transmission layer, with each layer having its own demodulation reference signal. This segmentation allows the system to support up to 4 transmission layers while using a relatively simple antenna arrangement, as each layer's reference signal can be independently configured and transmitted.
Solution Approach 2:
The patent designs a universal reference signal structure that can accommodate both single-antenna transmission and multi-antenna spatial multiplexing modes. The same reference signal framework serves multiple functions: it supports channel estimation for single-layer transmission and enables layer-specific channel estimation for multi-layer spatial multiplexing, thereby supporting high communication speeds without requiring completely different antenna arrangements.
3Measurement precision
If demodulation reference signals are configured for multiple transmission layers, then spatial multiplexing performance is improved, but signaling overhead increases
Solution Approach 1:
The patent merges the configuration of demodulation reference signals with existing uplink grant signaling structures. By integrating the reference signal configuration information into the uplink grant, the system reduces separate signaling overhead while still providing layer-specific reference signal configuration necessary for accurate channel estimation in spatial multiplexing modes.
Solution Approach 2:
The patent creates a universal reference signal configuration mechanism that serves both single-antenna and multi-antenna transmission modes. The same configuration framework is used regardless of the transmission mode, reducing the need for separate signaling for different transmission scenarios while maintaining the ability to provide layer-specific channel estimation when spatial multiplexing is employed.
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AI summary
Abstract: The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and to an apparatus for enabling a terminal to transmit a signal in a wireless communication system. The present invention provides a signal transmission method, comprising the steps of: receiving configuration information for multi-antenna transmission from a base station; configuring a multi-antenna transmission mode in accordance with the received configuration information; and transmitting an uplink channel having a plurality of symbols to the base station through multiple antennas. The present invention also provides an apparatus for carrying out said signal transmission method.