DMRS Resource Allocation Signaling for LTE Power Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In cellular mobile communication systems, especially in LTE and LTE-Advanced, the use of Demodulation Reference Signals (DMRS) for channel estimation and symbol detection leads to increased signaling overhead and complexity in multi-user MIMO scenarios due to varying power allocation and precoding requirements, making it difficult to maintain a fixed offset between DMRS and data power, which hampers system efficiency and flexibility.
Innovation Solution
A method is introduced to maintain a fixed power offset between DMRS and data for all layers in spatial multiplexing, allowing for flexible power allocation and reduced signaling overhead by using a specific DMRS distribution pattern and power offset parameter, enabling efficient channel estimation and demodulation, and allowing UEs to detect DMRS allocation information for interference suppression in MU-MIMO mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed power offset between DMRS and data is maintained, then power amplifier efficiency is improved and signaling overhead is reduced, but flexibility in multi-user power allocation is worsened
Solution Approach 1:
The patent introduces a power offset parameter that can be dynamically adjusted based on transmission conditions. By changing the power offset parameter, the system can adapt between fixed offset mode (for efficiency) and dynamic offset mode (for flexibility), resolving the contradiction between power amplifier efficiency and multi-user allocation flexibility.
2Measurement precision
If DMRS resource allocation is dynamically adjusted for different numbers of layers, then channel estimation accuracy is improved, but system signaling overhead is worsened
Solution Approach 1:
The patent pre-configures DMRS resource allocation patterns for different channel ranks. Instead of dynamically signaling resource allocation for each transmission, the system establishes predetermined patterns in advance, reducing signaling overhead while maintaining accurate channel estimation through appropriate pattern selection.
Solution Approach 2:
The patent uses channel rank as a parameter to select different DMRS resource allocation patterns. By changing the channel rank parameter, the system can adapt the DMRS configuration to match the number of spatial layers, ensuring accurate channel estimation without requiring extensive dynamic signaling.
3Adaptability or versatility
If multiple DMRS multiplexing approaches are supported, then system adaptability is improved, but maintaining fixed power offset becomes more difficult
Solution Approach 1:
The patent introduces a configurable power offset parameter that can be adjusted based on the selected multiplexing approach. This allows the system to maintain appropriate power relationships between DMRS and data regardless of whether FDM, CDM, or other multiplexing methods are used, managing the complexity through parameterization.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A method of notifying resource allocation for Demodulation Reference Signal (DMRS) is provided. A base station notifies to a user equipment a power offset value between an average EPRE value for data symbols and an average EPRE value for the DMRS at each layer in a semi-static or static manner. Also, the base station dynamically notifies to the user equipment a current channel rank or a current DMRS distribution pattern for the user equipment. The user equipment determines an allocated DMRS antenna port based on a correspondence between the received channel rank and an allocation of DMRS antenna port, thereby obtaining resource allocation information for the DMRS. The signaling overhead for power allocation in the system can be reduced, the efficiency of power amplifier can be improved and the flexibility of system scheduling can be increased. A method of notifying antenna port resource allocation for DMRS is also provided.