Dedicated Demodulation Reference Signal Resource Allocation in LTE-A
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Solution Overview
Problem
In mobile communication systems, particularly in LTE-A, the locations and multiplexing methods of dedicated demodulation data reference signals within Resource Blocks (RBs) are not determined, leading to inefficiencies in resource utilization and increased overhead.
Innovation Solution
A method to determine the location of dedicated demodulation data reference signals in Resource Elements (REs) within OFDM symbols in a non-control channel area of RBs, using a classification system for different numbers of layers and employing Walsh orthogonal codes for multiplexing, ensuring efficient resource allocation and reduced signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Common Reference Signals (CRS) are distributed on the whole system bandwidth to enable accurate channel estimation, then channel estimation accuracy is improved, but resource overhead increases significantly
Solution Approach 1:
The patent segments the reference signal functionality by introducing dedicated demodulation reference signals (DM-RS) that are specific to each user and layer, rather than using a single common reference signal for all users. This segmentation allows each user to have their own reference signal resources, reducing the overall overhead while maintaining accurate channel estimation for each user independently.
Solution Approach 2:
The patent applies local quality by making reference signals user-specific and layer-specific rather than common to all users. Each DM-RS is tailored to the specific user's modulation scheme, coding rate, and layer configuration, allowing optimized resource allocation where each reference signal occupies only the necessary resources for its specific purpose rather than distributing across the entire bandwidth.
2Productivity
If dedicated demodulation reference signals are pre-processed in the same way as data and defined on layers, then resource utilization efficiency is improved, but the reference signal cannot serve as a measurement reference signal
Solution Approach 1:
The patent segments reference signal functionality into two distinct types: Common Reference Signals (CRS) for measurement purposes and Dedicated Demodulation Reference Signals (DM-RS) for coherent demodulation. This segmentation allows each type to be optimized for its specific function without compromising the other, resolving the contradiction between resource efficiency and functional versatility.
3Adaptability or versatility
If the locations of REs occupied by dedicated demodulation reference signals and multiplexing methods among different layers are not determined, then system flexibility is maintained, but resource allocation efficiency decreases
Solution Approach 1:
The patent introduces dynamic resource allocation for DM-RS where the number of reference signal resources adapts to the actual number of layers and users. The resource allocation is determined by layer classification and code division multiplexing, allowing the system to dynamically adjust reference signal overhead based on current transmission conditions while maintaining efficient resource utilization.
4Ease of operation
If Common Reference Signals are used for all receiving ends, then channel estimation can be performed by all users, but signaling overhead increases when there are many transmitting antennas
Solution Approach 1:
The patent extracts the demodulation reference signal functionality from the common reference signal and creates a separate dedicated reference signal mechanism. This extraction removes the burden of providing comprehensive CRS for all users and antennas, instead providing targeted DM-RS only where needed for each user's demodulation, significantly reducing signaling overhead while maintaining channel estimation capability.
Data Source
AI summary
The present disclosure discloses a signal resource determination method, and the method includes that: carrying a dedicated demodulation data reference signal in a Resource Element (RE) on an Orthogonal Frequency Division Multiplexing (OFDM) symbol, wherein the OFDM symbol is in a non-control channel area of a Resource Block (RB) and carries a non-common reference signal.